Patent Publication Number: US-2022211387-A1

Title: Patient-specific surgical methods and instrumentation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 17/020,630 filed on Sep. 14, 2020, entitled “PATIENT-SPECIFIC SURGICAL METHODS AND INSTRUMENTATION”, which claims the benefit of U.S. Provisional Application No. 62/900,294, filed Sep. 13, 2019, which are hereby incorporated by reference in their entirety. This application is also claims the benefit of U.S. Provisional Application No. 63/190,551, filed May 19, 2021 and claims the benefit of U.S. Provisional Application No. 63/224,344, filed Jul. 21, 2021, which are hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to surgical devices, systems, instruments, and methods. More specifically, the present disclosure relates to patient-specific cutting guides and implants, and methods of designing and using the same. 
     BACKGROUND 
     Various bone conditions may be corrected using an osteotomy, in which one or more bones are cut, replaced, and/or reoriented. Cutting guides are often used to help the surgeon properly locate, position, and make one or more cuts. Unfortunately, many known cutting guides are not patient-specific, and can be difficult to properly position to perform the osteotomy on a specific patient. Even if properly positioned, many known cutting guides are difficult to secure at the desired position, without moving away from the desired position prior to performing the osteotomy. As a result, many known osteotomy procedures carry risk of an improper cut that fails to correct the underlying condition, or even endangers surrounding tissues. 
     SUMMARY 
     The various apparatus, devices, systems, and/or methods of the present disclosure have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available technology. One general aspect of the present disclosure can include a patient specific instrument for correcting a condition present in a patient. The patient specific instrument may include a body that may include: a proximal side, a distal side, a medial side, and a lateral side; an inferior side that may include a bone engagement surface shaped to match a first surface of a first bone and a second surface of a second bone of a joint; a superior side that may include a first guide feature and a second guide feature that together, with the bone engagement surface overlying the first surface and the second surface, are positioned to guide resection of the first bone and the second bone during a surgical osteotomy for correcting the condition. The instrument includes where the body is configured to seat transverse to the joint with the bone engagement surface engaging the first surface of the first bone and the second surface of the second bone. 
     Implementations may include one or more of the following features. The patient specific instrument where when the bone engagement surface seats over the joint: the first guide feature is configured to define a first cut surface formed by resection of the first bone; the second guide feature is configured to define a second cut surface formed by resection of the second bone; where the second cut surface extends inferiorly away from the first cut surface at a first angle measured from the first cut surface and extends posteriorly away from the first cut surface at a second angle measured relative to the first cut surface; and where the first cut surface is perpendicular to a longitudinal axis of the first bone. One of the first guide feature and the second guide feature may include a position and an orientation, at least one of which is based on patient imaging data. In one implementation, the patient imaging data is used to define a distance between at least one of a first top edge of the first guide feature and the first surface and a second top edge of the second guide feature and the second surface. 
     The body may include: a proximal arm extending from the body; and a distal arm extending from the body and away from the proximal arm; and where: the distal arm may include a first bone attachment feature positioned perpendicular to the first guide feature and parallel with a first alignment feature configured to be coupled to the first bone; the proximal arm may include a second bone attachment feature and a second alignment feature each positioned perpendicular to the second guide feature; and where the first alignment feature and first bone attachment feature are not aligned and the first alignment feature and the second alignment feature are configured to align when the first bone is rotated. The second bone attachment feature and the second alignment feature may include a single feature. 
     The body may extend between a lateral end of the joint and a medial end of the joint and the proximal arm and the distal arm are aligned and extend proximal to the lateral end of the joint. At least one of the body, the proximal arm, the distal arm, and the bone engagement surface of the inferior side of the body is configured to engage a dorsal surface of one or more of the first bone and the second bone. The first alignment feature and second alignment feature are configured to couple with an active compression instrument that compresses the first bone and the second bone for deployment of fasteners that connect the first bone and the second bone. The lateral side of the body may include a lateral superior surface and a lateral inferior surface that meet at a lateral edge, the lateral inferior surface angled to connect the inferior side of the body and the lateral edge such that the lateral inferior surface does not impinge upon soft tissue near the joint. 
     The medial side of the body may include a medial superior surface and a medial inferior surface that meet at a medial edge, the medial inferior surface angled to connect the inferior side of the body and the medial edge such that the medial inferior surface does not impinge upon soft tissue near the joint. The bone engagement surface of the inferior side of the body is configured to engage a dorsal surface of one or more of the first bone and the second bone. 
     One general aspect of the present disclosure can include a method for making a patient specific cutting guide configured to mitigate a condition present in a patient. The method includes accessing a bone model of one or more bones of a patient based on the condition and/or the bone model; defining one or more guide features of a preliminary cutting guide model for an osteotomy procedure, the preliminary cutting guide model may include a superior surface and an inferior surface; defining at least a portion of the inferior surface of the preliminary cutting guide model according to a topographical surface of at least one bone of the bone model such that the inferior surface substantially matches a contour of the topographical surface; and where the preliminary cutting guide model is configured for fabrication of a patient specific cutting guide corresponding to the preliminary cutting guide model. 
     Implementations may include one or more of the following features. The method may include defining one or more alignment features of the preliminary cutting guide model for the osteotomy procedure. Accessing the bone model further may include: modifying a bone model may include a first modeled bone and a second modeled bone of a joint of the patient such that the first modeled bone is rotated about a longitudinal axis of the first modeled bone from a first position to a second position; defining a first cut surface in the first modeled bone, where the first cut surface is perpendicular to the longitudinal axis of the first modeled bone; defining a first angle for a second cut surface of the second modeled bone, the first angle measured relative to the first cut surface and extends inferiorly away from the first cut surface; defining a second angle for the second cut surface of the second modeled bone, the second angle measured relative to the first cut surface and configured to mitigate the condition; modifying the bone model of the first modeled bone to include the first cut surface and the second modeled bone to include the second cut surface; and where the one or more guide features of a preliminary cutting guide model are configured to enable a surgeon to form the first cut surface and the second cut surface. 
     Defining one or more guide features of the preliminary cutting guide model further may include: defining a first slot configured to guide formation of a first cut surface of a first bone of the patient corresponding to a first modeled bone; defining a second slot configured to guide formation of a second cut surface of a second bone of the patient corresponding to a second modeled bone; and where the first slot and second slot are positioned such that fixing the first cut surface of the first bone to the second cut surface of the second bone mitigates the condition. The method may include selecting the preliminary cutting guide model from a repository of template cutting guide models, each template cutting guide model configured for an osteotomy procedure configured to correct one of a plurality of conditions. The method may include defining a coupler configured to engage an alignment guide, the alignment guide configured to indicate a resulting alignment of patient body parts upon completion of the osteotomy procedure. The bone model is derived from patient imaging data generated while the patient places their weight on at least one joint involved in the osteotomy procedure. 
     One general aspect of the present disclosure can include a system for correcting a condition present in a patient. The system may include a cut guide that may include: a first guide feature configured to define a first cut surface configured for resection of a first metatarsal of a patient, a second guide feature configured to define a second cut surface configured for resection of a medial cuneiform of a patient, an inferior side may include a bone engagement surface shaped to match a first surface of the first metatarsal and a second surface of the medial cuneiform, a medial cuneiform alignment feature coupled to the medial cuneiform, where one of the first guide feature and the second guide feature is configured based on patient imaging data such that fusion of the first metatarsal at the first cut surface to the medial cuneiform at the second cut surface mitigates the condition. The system includes a first metatarsal alignment feature coupled to the first metatarsal, the first metatarsal alignment feature configured to enable a user to rotate the first metatarsal from a malrotation position to a desired rotation position; and a compressor/distractor configured to engage the medial cuneiform alignment feature and the first metatarsal alignment feature and compress the first cut surface of the first metatarsal against the second cut surface of the medial cuneiform. 
     Implementations may include one or more of the following features. The system where: the first metatarsal alignment feature may include a pin guide configured to position alignment pins for a desired rotation angle of the first metatarsal about its longitudinal axis; the compressor/distractor may include a pair of legs that are closer to each other at distal end of each leg than at a proximal end of each leg. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages, nature, and additional features of exemplary embodiments of the disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only exemplary embodiments and are, therefore, not to be considered limiting of the disclosure&#39;s scope, the exemplary embodiments of the disclosure will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG. 1A  is a flowchart diagram depicting a method for correcting a bone condition, according to one embodiment. 
         FIG. 1B  is a flowchart diagram depicting a method for correcting bunion deformity of the human foot, according to one embodiment. 
         FIG. 2  is a perspective view of a portion of a foot with a bunion deformity to be treated through use of the methods of  FIGS. 1A and/or 1B , according to one embodiment. 
         FIGS. 3A, 3B, 3C, and 3D  are top perspective, alternative top perspective, front elevation, and bottom perspective views, respectively, of a patient-specific cutting guide, according to one embodiment 
         FIG. 4  is a perspective view of the foot of  FIG. 2 , with the cutting guide of  FIGS. 3A, 3B, 3C and 3D  properly positioned on the first cuneiform and the first metatarsal, but as yet not attached to the first cuneiform and the first metatarsal. 
         FIG. 5  is a perspective view of the foot of  FIG. 2 , with the cutting guide of  FIGS. 3A, 3B, 3C, and 3D  properly positioned on the first cuneiform and the first metatarsal and attached to the first cuneiform and the first metatarsal in preparation for resection of the first cuneiform and the first metatarsal, according to one embodiment. 
         FIG. 6A  is a perspective view of the foot of  FIG. 2 , after resection of the first cuneiform and the first metatarsal, removal of the cutting guide, and placement of the first metatarsal to abut the first cuneiform, according to one embodiment. 
         FIGS. 6B and 6C  are dorsal views of the foot of  FIG. 2 , before and after correction, respectively, according to one embodiment. 
         FIGS. 7A, 7B, 7C, and 7D  are top perspective, alternative top perspective, front elevation, and bottom perspective views, respectively, of a patient-specific cutting guide according to one alternative embodiment. 
         FIGS. 8A, 8B, and 8C  are dorsal pre-operative, dorsal post-operative, and lateral post-operative views, respectively, of a foot treated with an Evans calcaneal osteotomy, according to one embodiment. 
         FIGS. 9A and 9B  are dorsal post-operative and lateral post-operative views, respectively, of a foot treated with a medializing calcaneal osteotomy, according to one embodiment. 
         FIG. 10  is a rear, perspective view of the foot of  FIG. 2 , after performance of an Evans calcaneal osteotomy and a medializing calcaneal osteotomy with patient-specific instruments and/or implants, according to one embodiment. 
         FIG. 11  is a perspective view of the implant of  FIG. 10 , in isolation, according to one embodiment. 
         FIGS. 12A, 12B, 12C, 12D, 12E, 12F, 12G, and 12H  are top perspective, top, bottom, front elevation, rear elevation, right, left, and alternative top perspective, respectively, of a patient-specific cutting guide according to one alternative embodiment. 
         FIG. 13  illustrates a perspective view of a first cuneiform and first metatarsal with one embodiment of a cutting guide secured to the two bones. 
         FIG. 14  illustrates a perspective view of a first cuneiform and first metatarsal with one embodiment of a cutting guide secured to the two bones. 
         FIG. 15  illustrates an exemplary embodiment of a parallel distractor that can be used with certain embodiments. 
         FIG. 16  illustrates an exemplary embodiment of a parallel distractor that can be used with certain embodiments. 
         FIG. 17  is a flowchart diagram depicting a method for generating one or more patient specific instruments configured to correct a bone condition, according to one embodiment. 
         FIG. 18  illustrates an exemplary system configured to generate one or more patient specific instruments configured to correct a bone condition, according to one embodiment. 
         FIGS. 19A-19H  are top perspective, top perspective, bottom, front elevation, rear elevation, right, and left, and alternative top perspective, respectively, of a patient-specific cutting guide according to one embodiment. 
         FIG. 20  illustrates a perspective view of a first cuneiform and a first metatarsal with one embodiment of a patient-specific cutting guide positioned over a tarsometatarsal (“TMT”) joint. 
         FIGS. 21A, 21B  illustrate a perspective view of an alignment guide and of a first cuneiform and a first metatarsal with one embodiment of a patient-specific cutting guide according to one embodiment. 
         FIGS. 22A-22H  are top perspective, top, bottom, front elevation, rear elevation, right, left, and alternative top perspective, respectively, of a patient-specific cutting guide according to one embodiment. 
         FIG. 23  illustrates a perspective view of a first cuneiform and a first metatarsal with one embodiment of a patient-specific cutting guide positioned over a TMT joint. 
         FIG. 24A  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 23  with one embodiment of a pin guide. 
         FIG. 24B  illustrates a diagram representative of a cross-sectional view of first metatarsal  230  from a proximal base looking towards the distal head. 
         FIG. 24C  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 24A  with a pin guide connected. 
         FIG. 25A  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 23  with one embodiment of a de-rotation handle. 
         FIG. 25B  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 25A  with the de-rotation handle and first metatarsal rotated. 
         FIG. 26  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIGS. 24A, 25A  with a compressor/distractor and cross joint guide. 
         FIG. 27  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIGS. 24A, 25A  with a compressor/distractor and fastener(s). 
         FIG. 28  illustrates a perspective view of an exemplary system for correcting a condition in accordance with one embodiment. 
         FIG. 29  is a flow chart diagram of one example method for making a patient specific cutting guide according to one embodiment. 
         FIGS. 30A-30C  illustrates perspective views of an exemplary preliminary cutting guide model modified in accordance with one embodiment for use as a patient-specific cutting guide. 
         FIG. 31  is a flow chart diagram of one example method for using a patient specific cutting guide according to one embodiment to mitigate a condition present in a patient. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus, system, and method is not intended to limit the scope of the disclosure but is merely representative of exemplary embodiments. 
     The phrases “connected to,” “coupled to” and “in communication with” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be functionally coupled to each other even though they are not in direct contact with each other. The term “abutting” refers to items that are in direct physical contact with each other, although the items may not necessarily be attached together. The phrase “fluid communication” refers to two features that are connected such that a fluid within one feature can pass into the other feature. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
     Standard medical planes of reference and descriptive terminology are employed in this disclosure. While these terms are commonly used to refer to the human body, certain terms are applicable to physical objects in general. A standard system of three mutually perpendicular reference planes is employed. A sagittal plane divides a body into right and left portions. A coronal plane divides a body into anterior and posterior portions. A transverse plane divides a body into superior and inferior portions. A mid-sagittal, mid-coronal, or mid-transverse plane divides a body into equal portions, which may be bilaterally symmetric. The intersection of the sagittal and coronal planes defines a superior-inferior or cephalad-caudal axis. The intersection of the sagittal and transverse planes defines an anterior-posterior axis. The intersection of the coronal and transverse planes defines a medial-lateral axis. The superior-inferior or cephalad-caudal axis, the anterior-posterior axis, and the medial-lateral axis are mutually perpendicular. 
     Anterior means toward the front of a body. Posterior means toward the back of a body. Superior or cephalad means toward the head. Inferior or caudal means toward the feet or tail. Medial means toward the midline of a body, particularly toward a plane of bilateral symmetry of the body. Lateral means away from the midline of a body or away from a plane of bilateral symmetry of the body. Axial means toward a central axis of a body. Abaxial means away from a central axis of a body. Ipsilateral means on the same side of the body. Contralateral means on the opposite side of the body from the side which has a particular condition or structure. Proximal means toward the trunk of the body. Proximal may also mean toward a user, viewer, or operator. Distal means away from the trunk. Distal may also mean away from a user, viewer, or operator. Dorsal means toward the top of the foot or other body structure. Plantar means toward the sole of the foot or toward the bottom of the body structure. 
     Antegrade means forward moving from a proximal location/position to a distal location/position or moving in a forward direction. Retrograde means backward moving from a distal location/position to a proximal location/position or moving in a backwards direction. Sagittal refers to a midline of a patient&#39;s anatomy, which divides the body into left or right halves. The sagittal plane may be in the center of the body, splitting it into two halves. Prone means a body of a person lying face down. Supine means a body of a person lying face up. 
     The present disclosure discloses surgical systems and methods by which a bone condition, such as a deformity, may be corrected using patient-specific instrumentation. Known methods of correcting bone conditions are often limited to a finite range of discretely sized instruments. A patient with an unusual condition, or anatomy that falls between instrument sizes, may not be readily treated with such systems. One example is correction of a bunion, in particular, via adjustment of the angulation between a cuneiform and a metatarsal. 
       FIG. 1A  is a flowchart diagram depicting a method  100  for correcting a bone condition, according to one embodiment. The method  100  may be used for any of a wide variety of bone conditions, including but not limited to deformities, fractures, joint failure, and/or the like. Further, the method  100  may provide correction with a wide variety of treatments, including but not limited to arthroplasty, arthrodesis, fracture repair, and/or the like. 
     As shown, the method  100  may begin with a step  102  in which a CT scan (or another three-dimensional image, also referred to as medical imaging) of the patient&#39;s anatomy is obtained. The step  102  may entail capturing a scan of only the particular bone(s) to be treated, or may entail capture of additional anatomic information, such as the surrounding tissues. Additionally or alternatively, the step  102  may entail receiving a previously captured image, for example, at a design and/or fabrication facility. Performance of the step  102  may result in possession of a three-dimensional model of the patient&#39;s anatomy, or three-dimensional surface points that can be used to construct such a three-dimensional model. 
     As used herein, “medical imaging” refers to a technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease. Medical imaging may be used to establish a database of normal anatomy and physiology to make possible identification of abnormalities. Medical imaging in its widest sense, is part of biological imaging and incorporates radiology, which uses the imaging technologies of X-ray radiography, magnetic resonance imaging, ultrasound, endoscopy, elastography, tactile imaging, thermography, medical photography, nuclear medicine functional imaging techniques as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Another form of X-ray radiography includes computerized tomography (CT) scans in which a computer controls the position of the X-ray sources and detectors. Magnetic Resonance Imaging (MRI) is another medical imaging technology. Measurement and recording techniques that are not primarily designed to produce images, such as electroencephalography (EEG), magnetoencephalography (MEG), electrocardiography (ECG), and others, represent other technologies that produce data susceptible to representation as a parameter graph vs. time or maps that contain data about the measurement locations. These technologies may be considered forms of medical imaging in certain disciplines. (Search “medical imaging” on Wikipedia.com Jun. 16, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 23, 2021.) Data, including images, text, and other data associated with medical imaging is referred to as patient imaging data. As used herein, “patient imaging data” refers to data identified, used, collected, gathered, and/or generated in connection with medical imaging and/or medical imaging data. Patient imaging data can be shared between users, systems, patients, and professionals using a common data format referred to as Digital Imaging and Communications in Medicine (DICOM) data. DICOM data is a standard format for storing, viewing, retrieving, and sharing medical images. 
     As used herein, “medical image computing” or “medical image processing” refers to systems, software, hardware, components, and/or apparatus that involve and combine the fields of computer science, information engineering, electrical engineering, physics, mathematics and medicine. Medical image computing develops computational and mathematical methods for working with medical images and their use for biomedical research and clinical care. One goal for medical image computing is to extract clinically relevant information or knowledge from medical images. While closely related to the field of medical imaging, medical image computing focuses on the computational analysis of the images, not their acquisition. The methods can be grouped into several broad categories: image segmentation, image registration, image-based physiological modeling, and others. (Search “medical image computing” on Wikipedia.com Jun. 24, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 24, 2021.) Medical image computing may include one or more processors or controllers on one or more computing devices. Such processors or controllers may be referred to herein as medical image processors. Medical imaging and medical image computing together can provide systems and methods to image, quantify and fuse both structural and functional information about a patient in vivo. These two technologies include the transformation of computational models to represent specific subjects/patients, thus paving the way for personalized computational models. Individualization of generic computational models through imaging can be realized in three complementary directions: definition of the subject-specific computational domain (anatomy) and related subdomains (tissue types); definition of boundary and initial conditions from (dynamic and/or functional) imaging; and characterization of structural and functional tissue properties. Medical imaging and medical image computing enable in the translation of models to the clinical setting with both diagnostic and therapeutic applications. (Id.) In certain embodiments, medical image computing can be used to generate a bone model, a patient specific model, and/or a patent specific instrument from medical imaging and/or medical imaging data. 
     As used herein, “model” refers to an informative representation of an object, person or system. Representational models can be broadly divided into the concrete (e.g. physical form) and the abstract (e.g. behavioral patterns, especially as expressed in mathematical form). In abstract form, certain models may be based on data used in a computer system or software program to represent the model. Such models can be referred to as computer models. Computer models can be used to display the model, modify the model, print the model (either on a 2D medium or using a 3D printer or additive manufacturing technology). Computer models can also be used in environments with models of other objects, people, or systems. Computer models can also be used to generate simulations, display in virtual environment systems, display in augmented reality systems, or the like. Computer models can be used in Computer Aided Design (CAD) and/or Computer Aided Manufacturing (CAM) systems. Certain models may be identified with an adjective that identifies the object, person, or system the model represents. For example, a “bone” model is a model of a bone, and a “heart” model is a model of a heart. (Search “model” on Wikipedia.com Jun. 13, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 23, 2021.) As used herein, “additive manufacturing” refers to a manufacturing process in which materials are joined together in a process that repeatedly builds one layer on top of another to generate a three-dimensional structure or object. Additive manufacturing may also be referred to using different terms including: additive processes, additive fabrication, additive techniques, additive layer manufacturing, layer manufacturing, freeform fabrication, ASTM F2792 (American Society for Testing and Materials), and 3D printing. Additive manufacturing can build the three-dimensional structure or object using computer-controlled equipment that applies successive layers of the material(s) based on a three-dimensional model that may be defined using Computer Aided Design (CAD) software. Additive manufacturing can use a variety of materials including polymers, thermoplastics, metals, ceramics, biochemicals, and the like. Additive manufacturing may provide unique benefits, as an implant together with the pores and/or lattices can be directly manufactured (without the need to generate molds, tool paths, perform any milling, and/or other manufacturing steps). 
     After the step  102  has been carried out, the method  100  may proceed to a step  104  in which a CAD model of the patient&#39;s anatomy (including one or more bones) is generated. The CAD model may be one example of a bone model. The CAD model may be of any known format, including but not limited to SolidWorks, Catia, AutoCAD, or DXF. In some embodiments, customized software may be used to generate the CAD model from the CT scan. The CAD model may only include the bone(s) to be treated and/or may include surrounding tissues. In alternative embodiments, the step  104  may be omitted, as the CT scan may capture data that can directly be used in future steps without the need for conversion. 
     In one embodiment, the CAD model generated and/or patient-specific instrumentation, implants, and/or plan for conducting an operative procedure, may be enhanced by the use of advanced computer analysis, machine learning, and/or automated/artificial intelligence. For example, these technologies may be used to revise a set of steps for a procedure such that a more desirable outcome is achieved. 
     In a step  106 , the CAD model and/or CT scan data may be used to model patient-specific instrumentation that can be used to correct the condition, as it exists in the patient&#39;s anatomy. In some embodiments, any known CAD program may be used to view and/or manipulate the CAD model and/or CT scan, and generate one or more instruments that are matched specifically to the size and/or shape of the patient&#39;s bone(s). In some embodiments, such instrumentation may include a cutting guide that is attachable to one or more bones, with one or more guide features that facilitate resection of the one or more bones pursuant to a procedure such as arthroplasty or arthrodesis. In some embodiments, performance of the step  106  may include modelling an instrument with a bone apposition surface that is shaped to match the contour of a surface of the bone, such that the bone apposition surface can lie directly on the corresponding contour. 
     As used herein, a “resection” refers to a method, procedure, or step that removes tissue from another anatomical structure or body. A resection is typically performed by a surgeon on a part of a body of a patient. (Search “surgery” on Wikipedia.com May 26, 2021. CC-BY-SA 3.0 Modified. Accessed May 26, 2021.) Resection may be used as a noun or a verb. In the verb form, the term is “resect” and refers to an act of performing, or doing, a resection. Past tense of the verb resect is resected. 
     As used herein, a “guide” refers to a part, component, or structure designed, adapted, configured, or engineered to guide or direct one or more other parts, components, or structures. A guide may be part of, integrated with, connected to, attachable to, or coupled to, another structure. In one embodiment, a guide may include a modifier that identifies a particular function, location, orientation, operation, type, and/or a particular structure of the guide. Examples of such modifiers applied to a guide, include, but are not limited to, “pin guide” that guides or directs one or more pins, a “cutting guide” that guides or directs the making or one or more cuts, and the like. As used herein, “feature” refers to a distinctive attribute or aspect of something. (Search “feature” on google.com. Oxford Languages, 2021. Web. 20 Apr. 2021.) A feature may include a modifier that identifies a particular function or operation and/or a particular structure relating to the feature. Examples of such modifiers applied to a feature, include, but are not limited to, “attachment feature,” “securing feature,” “protruding feature,” “engagement feature,” “disengagement feature,” “guide feature”, and the like. 
     Those of skill in the art will appreciate that a guide feature may take a variety of forms and may include a single feature or one or more features that together form the guide feature. In certain embodiments, the guide feature may take the form of one or more slots. Alternatively, or in addition, a guide feature may be referenced using other names including, but not limited to, channel, cut channels, and the like. 
     In a step  108 , the model(s) may be used to manufacture patient-specific instrumentation and/or implants. This may be done via any known manufacturing method, including casting, forging, milling, additive manufacturing, and/or the like. Additive manufacturing may provide unique benefits, as the model may be directly used to manufacture the instrumentation and/or implants (without the need to generate molds, tool paths, and/or the like beforehand). Such instrumentation may optionally include a cutting guide with the bone apposition surface and one or more guide features as described above. 
     In addition to, or in the alternative to the step  108 , the model(s) may be used to select from available sizes of implants and/or instruments and advise the surgeon accordingly. For example, where a range of cutting guides are available for a given procedure, analysis of the CAD data may facilitate pre-operative selection of the optimal cutting guide and/or optimal placement of the cutting guide on the bone. Similarly, if a range of implants may be used for a given procedure, analysis of the CAD data may facilitate pre-operative selection of the optimal implant(s). More particularly, properly-sized spacers, screws, bone plates, and/or other hardware may be pre-operatively selected. 
     Thus, the result of the step  108  may be provision, to the surgeon, of one or more of the following: (1) one or more patient-specific instruments; (2) one or more patient-specific implants; (3) an instrument, selected from one or more available instrument sizes and/or configurations; (4) an implant, selected from one or more available implant sizes and/or configurations; (5) instructions for which instrument(s) to select from available instrument sizes and/or configurations; (6) instructions for which implant(s) to select from available implant sizes and/or configurations; (7) instructions for proper positioning or anchorage of one or more instruments to be used in the procedure; and (8) instructions for proper positioning or anchorage of one or more implants to be used in the procedure. These items may be provided to the surgeon directly, or to a medical device company or representative, for subsequent delivery to the surgeon. 
     In a step  110 , the manufactured instrumentation may be used in surgery to facilitate treatment of the condition. In some embodiments, this may entail placing the modelled bone apposition surface against the corresponding contour of the bone used to obtain its shape, and then using the guide feature(s) to guide resection of one or more bones. Then the bone(s) may be further treated, for example, by attaching one or more joint replacement implants (in the case of joint arthroplasty), or by attaching bone segments together (in the case of arthrodesis or fracture repair). Prior to completion of the step  110 , the instrumentation may be removed from the patient, and the surgical wound may be closed. 
     As mentioned previously, the method  100  may be used to correct a wide variety of bone conditions. One example of the method  100  will be shown and described in connection with  FIG. 1B , for correction of a bunion deformity of the foot. 
     In certain embodiments, one or more of a method, apparatus, and/or system of the disclosed solution can be used for training a surgeon to perform a patient-specific procedure or technique. In one embodiment, the CAD model generated and/or patient-specific instrumentation, implants, and/or plan for conducting an operative procedure can be used to train a surgeon to perform a patient-specific procedure or technique. 
     In one example embodiment, a surgeon may submit a CT scan of a patient&#39;s foot to an apparatus or system that implements the disclosed solution. Next, a manual or automated process may be used to generate a CAD model and for making the measurements and correction desired for the patient. In the automated process, advanced computer analysis, machine learning and automated/artificial intelligence may be used to generate a CAD model and/or one or more patient-specific instruments and/or operation plans. For example, a patient-specific cutting guide may be fabricated that is registered to the patient&#39;s anatomy using a computer-aided machine (CAM) tool. In addition, a CAM tool may be used to fabricate a 3D structure representative of the patient&#39;s anatomy, referred to herein as a patient-specific synthetic cadaver. (e.g. one or more bones of a patient&#39;s foot). Next, the patient-specific cutting guide and the patient-specific synthetic cadaver can be provided to a surgeon who can then rehearse an operation procedure in full before going into an operating room with the patient. 
     In certain embodiments, the patient-specific cutting guide can be used to preposition and pre-drill a plate system for fixation purposes. Such plate systems may be optimally placed, per a CT scan, after a correction procedure for optimal fixation outcome. In another embodiment, the CAD model and/or automated process such as advanced computer analysis, machine learning and automated/artificial intelligence may be used to measure a depth of the cut through the patient-specific cutting guide for use with robotics apparatus and/or systems which would control the depth of each cut within the guide to protect vital structures below or adjacent to a bone being cut. In another embodiment, the CAD model and/or automated process such as advanced computer analysis, machine learning and automated/artificial intelligence may be used to define desired fastener (e.g. bone screw) length and/or trajectories through a patient-specific cutting guide and/or implant. The details for such lengths, trajectories, and components can be detailed in a report provided to the surgeon preparing to do a procedure. 
       FIG. 1B  is a flowchart diagram depicting a method  120  for correcting bunion deformity of the human foot, according to one embodiment. The method  120  may be used to carry out an arthrodesis procedure by which the first metatarsocuneiform joint is removed and the first cuneiform and first metatarsal are secured together in a manner that properly aligns the first metatarsal, providing correction of the deformity. 
     As shown, the method  120  may begin with a step  122  in which a CT scan (or another three-dimensional image) of the patient&#39;s foot is obtained. The step  122  may entail capturing a scan of only the first cuneiform and first metatarsal, or may entail capture of additional anatomic information, such as the entire foot. Additionally or alternatively, the step  122  may entail receipt of previously captured image data. Capture of the entire foot in the step  122  may facilitate proper alignment of the first metatarsal with the rest of the foot (for example, with the second metatarsal). Performance of the step  122  may result in generation of a three-dimensional model of the patient&#39;s foot, or three-dimensional surface points that can be used to construct such a three-dimensional model. 
     After the step  122  has been carried out, the method  120  may proceed to a step  124  in which a CAD model of the relevant portion of the patient&#39;s anatomy is generated. The CAD model may optionally include the bones of the entire foot, like the CT scan obtained in the step  122 . In alternative embodiments, the step  124  may be omitted in favor of direct utilization of the CT scan data, as described in connection with the step  104 . 
     In a step  126 , the CAD model and/or CT scan data may be used to model patient-specific instrumentation that can be used to correct the bunion deformity. Such instrumentation may include a cutting guide that is attachable to the first cuneiform and the first metatarsal, with two guide features that facilitate resection of the cuneiform and the metatarsal in preparation for arthrodesis. In some embodiments, performance of the step  126  may include modelling the cutting guide with a bone apposition surface that is shaped to match contours of the surfaces of the cuneiform and the metatarsal, such that the bone apposition surface can lie directly on the corresponding contours of the first cuneiform and the first metatarsal. 
     In a step  128 , the model(s) may be used to manufacture patient-specific instrumentation and/or instruments. This may include manufacturing the cutting guide with the bone apposition surface and the guide features as described above. As in the step  108 , the step  128  may additionally or alternatively involve provision of one or more instruments and/or implants from among a plurality of predetermined configurations or sizes. Further, the step  128  may additionally or alternatively involve provision of instructions for placement and/or anchorage of one or more instruments and/or instruments to carry out the procedure. 
     In a step  130 , the manufactured cutting guide may be used in surgery to facilitate treatment of the condition. Specifically, the bone apposition surface of the cutting guide may be placed against the corresponding contours of the first cuneiform and the first metatarsal. The guide features (for example, slots) may then be positioned on either side of the joint between the first cuneiform and the first metatarsal to guide resection of the first metatarsal and the first cuneiform to remove the intervening joint. The cutting guide may then be removed, and the remaining portions of the first cuneiform and the first metatarsal may be placed to abut each other. The cutting guide may have been shaped such that the cuts made to the first cuneiform and the first metatarsal are properly oriented to bring the first metatarsal back into its proper orientation relative to the rest of the foot. The first cuneiform and the first metatarsal may be secured together using a bone plate or the like. The surgical wound may be closed to allow the foot to heal, and to allow the first cuneiform and the first metatarsal to fuse together. 
     The method  100  and the method  120  are merely exemplary. Those of skill in the art will recognize that various steps of the method  100  and the method  120  may be reordered, omitted, and/or supplemented with additional steps not specifically shown or described herein. 
     As mentioned previously, the method  120  is one species of the method  100 ; the present disclosure encompasses many different procedures, performed with respect to many different bones and/or joints of the body. Exemplary steps and instrumentation for the method  120  will further be shown and described in connection with  FIGS. 2 through 7D . Those of skill in the art will recognize that the method  120  may be used in connection with different instruments; likewise, the instruments of  FIGS. 2 through 7D  may be used in connection with methods different from the method  100  and the method  120 . 
       FIG. 2  is a perspective view of a portion of a foot  200  with a bunion deformity to be treated through use of the method  100  (and more specifically, the method  120 ) described above. The foot  200  may have a first cuneiform  210 , a second cuneiform  220 , a first metatarsal  230 , and a second metatarsal  240 . The first cuneiform  210  and the second cuneiform  220  may be joined together at a first metatarsocuneiform joint, and the first metatarsal  230  and the second metatarsal  240  may be joined together at a second metatarsocuneiform joint. 
     The first metatarsal  230  may be excessively angled in a medial direction  270  (i.e., toward the lower left-hand corner of the page), causing a painful protrusion at a distal end  250  of the first metatarsal  230 , and further causing the phalanges (not shown) attached to the distal end  250  to be angled excessively in a lateral direction  260  (i.e., pointing toward the other phalanges of the foot, rather than pointing directly forward). The excessive medial angulation of the first metatarsal  230  may also result in an excessive gap between the first metatarsal  230  and the second metatarsal  240 . 
     The first metatarsal  230  may further be offset in a plantar direction  280  or in a dorsal direction  290 , relative to the remainder of the foot  200 . Accordingly, the orientation of the first metatarsal  230  may need to be adjusted to move the distal end  250  in the lateral direction  260  and in the plantar direction  280  and/or in the dorsal direction  290 . 
     Every deformity is different; accordingly, the degree of angular adjustment needed in each direction may be different for every patient. Use of a patient-specific cutting guide may help the surgeon obtain the optimal realignment in the lateral direction  260  and in the plantar direction  280  or the dorsal direction  290 . Conversely, use of one of several differently-sized cutting guides may provide only approximate correction, as the surgeon may not have a guide that precisely matches the correction needed for the foot  200 , and must thus choose the cutting guide that most closely provides the desired correction. Such differently sized cutting guides would not be contoured to fit the first cuneiform  210  or the first metatarsal  230 , thus introducing additional potential for error as the surgeon must properly align the selected cutting guide. 
     Thus, providing a patient-specific cutting guide may provide unique benefits. Specifically, the patient-specific cutting guide may provide precise correction of the deformity present in the foot  200  and may also reduce the likelihood of improper correction due to misalignment of the cutting guide on the foot  200 . The optimal cut provided by such a cutting guide may further reduce the likelihood that additional procedures, such as attachment of the first metatarsal  230  to the second metatarsal  240  to each other with screws or the like, will be needed to provide the desired correction. Any such additional procedure carries its own added surgical burden and risk of failure. Thus, the use of patient-specific instrumentation may shorten surgery, accelerate recovery, and reduce the risk of complications. 
       FIGS. 3A, 3B, 3C, and 3D  are top perspective, alternative top perspective, front elevation, and bottom perspective views, respectively, of a patient-specific cutting guide, or cutting guide  300 , according to one embodiment. The cutting guide  300  may be designed to facilitate resection of the first cuneiform  210  and the first metatarsal  230  with planar cuts at the proper angles to provide dual-plane correction of the orientation of the first metatarsal  230 , thereby providing correction in the lateral direction  260  and in the plantar direction  280  or the dorsal direction  290 . 
     As shown, the cutting guide  300  may have a body  310  with a monolithic construction and the general shape of a rectangular prism. The cutting guide  300  may further have a joint alignment feature that helps align the body  310  with the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230 . The joint alignment feature may consist of a joint probe  320  that extends from the body  310  and has a blade-like shape. The body  310  may reside on the dorsal surfaces of the first cuneiform  210  and the first metatarsal  230 , while the joint probe  320  may protrude into the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230  to provide proper alignment of the body  310  with the metatarsocuneiform joint. 
     The body  310  may have a bone facing side  330  that, upon attachment of the body  310  to the first cuneiform  210  and the first metatarsal  230 , is to face toward the first cuneiform  210  and the first metatarsal  230 . The body  310  may also have an outward-facing side  332  that, upon attachment of the body  310  to the first cuneiform  210  and the first metatarsal  230 , faces outward, away from the first cuneiform  210  and the first metatarsal  230 . Further, the body  310  may have one or more bone attachment features that facilitate attachment of the body  310  to the first cuneiform  210  and/or the first metatarsal  230 . Such bone attachment features may comprise any of a wide variety of holes, spikes, fastening devices, and/or the like. As embodied in  FIGS. 3A through 3D , the bone attachment features may take the form of holes  340  that extend from the bone facing side  330  to the outward-facing side  332  and/or one or more fixation devices. The holes  340  may be shaped to accommodate pins, K-wires, and/or other elongated bone fixation elements that can be anchored in the first cuneiform  210  and/or the first metatarsal  230  to keep the cutting guide  300  in place. 
     The bone facing side  330  may be custom contoured to match the shapes of the first cuneiform  210  and/or the first metatarsal  230 . As embodied in  FIGS. 3A through 3D , the bone facing side  330  may have a cuneiform apposition portion  342  shaped to lie against the dorsal surface of the first cuneiform  210 , and a metatarsal apposition portion  344  shaped to lie against the dorsal surface of the first metatarsal  230 . As shown, the cuneiform apposition portion  342  may be contoured to match the contour of the dorsal surface of the first cuneiform  210  on which it is to rest, and the metatarsal apposition portion  344  may similarly be contoured to match the contour of the dorsal surface of the first metatarsal  230  on which it is to rest. Thus, the body  310  may have only one stable position and orientation relative to the first cuneiform  210  and the first metatarsal  230 . 
     Generation of the contours of the cuneiform apposition portion  342  and the metatarsal apposition portion  344  may be performed relative easily in various CAD programs. In some embodiments, the shapes of the corresponding dorsal surfaces of the first cuneiform  210  and the first metatarsal  230  may be obtained directly from the CAD models and/or CT scan data, and simply copied onto the model for the body  310  of the cutting guide  300 . Various operations may be used to copy surfaces from one object to another. Additionally or alternatively, various Boolean operations, such as a Boolean subtraction operation, may be used to remove material from a model for the body  310  with a shape that matches the dorsal surfaces of the first cuneiform  210  and the first metatarsal  230 . 
     The body  310  may further have guide features that guide a cutter to resect the first cuneiform  210  and the first metatarsal  230  in the manner needed to make the desired correction. For example, the guide features may be used to guide a planar cutting blade, an arcuate cutting blade, a drill or mill, a burr, and/or the like. 
     In the embodiment of  FIGS. 3A through 3D , the guide features may guide a reciprocating planar blade, such as that of a surgical bone saw, that forms planar cuts in the first cuneiform  210  and the first metatarsal  230 . Thus, the guide features may take the form of a first slot  350  and a second slot  352 , which may be positioned toward the center of the body  310 , on opposite sides of the joint probe  320 . Thus, upon proper positioning of the cutting guide  300 , the first slot  350  may be positioned over the first cuneiform  210  to facilitate resection of the first cuneiform  210 , while the second slot  352  may be positioned over the first metatarsal  230  to facilitate resection of the first metatarsal  230 . 
     In alternative embodiments, a guide feature may be designed to guide a different type of cutter, such as a drill, mill, or side-cutting burr. In such embodiments, the guide feature may not be a slot, but may instead be a translatable or rotatable cutter retainer that guides translation and/or rotation of the cutter relative to the bone. 
     Returning to  FIGS. 3A through 3D , the body  310  may further have features that facilitate proper positioning of the cutting guide  300  on the first cuneiform  210  and the first metatarsal  230 . More specifically, the body  310  may have a first bone indicator  360  with the text “CUN,” indicating that the end of the body  310  with the first bone indicator  360  is to be positioned over the first cuneiform  210 . Similarly, the body  310  may have a second bone indicator  362  with the text “MET,” indicating that the end of the body  310  with the second bone indicator  362  is to be positioned over the first metatarsal  230 . In addition, the body  310  may have a side indicator  370  with the text “LEFT,” indicating that the cutting guide  300  is to be used in connection with the patient&#39;s left foot. The side indicator  370  may be particularly helpful when bunion corrections are to be provided on both of the patient&#39;s feet. In such a case, the surgeon may manufacture or receive two separate cutting guides: one for the left foot (the foot  200  of  FIG. 2 ) and another for the right foot (not shown). 
       FIG. 4  is a perspective view of the foot  200  of  FIG. 2 , with the cutting guide  300  of  FIGS. 3A, 3B, 3C and 3D  properly positioned on the first cuneiform  210  and the first metatarsal  230 , but as yet not attached to the first cuneiform  210  and the first metatarsal  230 . The surgeon has made the incision(s) to expose the dorsal surfaces of the first cuneiform  210  and the first metatarsal  230 , and has inserted the cutting guide  300  such that the cuneiform apposition portion  342  (identified by the first bone indicator  360  on the outward-facing side  332  of the body  310 ) is resting on the corresponding dorsal surface of the first cuneiform  210 , and the metatarsal apposition portion  344  (identified by the second bone indicator  362  on the outward-facing side  332  of the body  310 ) is resting on the corresponding dorsal surface of the first metatarsal  230 . Since the cuneiform apposition portion  342  and the metatarsal apposition portion  344  are contoured to match the bone surfaces on which they rest, the body  310  may readily slide into its proper position on the first cuneiform  210  and the first metatarsal  230 . 
     Notably, the joint probe  320  (not visible) may reside between the first cuneiform  210  and the first metatarsal  230  (i.e., distal to the first cuneiform  210  and proximal to the first metatarsal  230 ). The surgeon may need to cut the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230  to form a space between the first cuneiform  210  and the first metatarsal  230  to receive the joint probe  320 . Positioning the joint probe  320  in this space may further help to ensure that the cutting guide  300  is properly aligned relative to the first cuneiform  210  and the first metatarsal  230 . 
       FIG. 5  is a perspective view of the foot  200  of  FIG. 2 , with the cutting guide  300  of  FIGS. 3A, 3B, 3C, and 3D  properly positioned on the first cuneiform  210  and the first metatarsal  230  and attached to the first cuneiform  210  and the first metatarsal  230  in preparation for resection of the first cuneiform  210  and the first metatarsal  230 . Specifically, pins  500  may be inserted through the holes  340  in the body  310  and anchored in the first cuneiform  210  and the first metatarsal  230 . Each of the pins  500  may have a sharp and/or threaded distal end that can penetrate and/or readily be retained in the bone of the first cuneiform  210  or the first metatarsal  230 . Additionally or alternatively, a drill or other hole-forming instrument may be used to pre-form holes in the first cuneiform  210  and/or the first metatarsal  230  to receive the distal ends of the pins  500 . 
     As shown, the body  310  may have two holes  340  positioned over the first cuneiform  210 , and two holes  340  positioned over the first metatarsal  230 . This is merely exemplary; in some embodiments, a cutting guide may be secured to one of the first cuneiform  210  and the first metatarsal  230  or may be secured to either of the first cuneiform  210  and the first metatarsal  230  with one pin  500 , or with more than two pins  500 . Further, in some alternative embodiments, different fasteners may be used, such as screws, clamps, clips, and/or the like. 
     Once the cutting guide  300  has been secured relative to the first cuneiform  210  and the first metatarsal  230 , the first cuneiform  210  and the first metatarsal  230  may be resected. In some embodiments, a reciprocating blade may be inserted into the first slot  350  and moved medially and laterally, between opposite ends of the first slot  350 , to make a planar cut that removes the distal end of the first cuneiform  210 . Similarly, the reciprocating blade (or a different reciprocating blade) may be inserted into the second slot  352  and moved medially and laterally, between opposite ends of the second slot  352 , to make a planar cut that removes the proximal end of the first metatarsal  230 . The cuts in the first cuneiform  210  and the first metatarsal  230  may be made in either order. In either case, once both cuts are made, the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230  may be removed, resulting in exposure of “bleeding” bone at the distal end of the first cuneiform  210  and the proximal end of the first metatarsal  230 . The cutting guide  300  may be removed, along with some or all of the pins  500 . If desired, at least two of the pins  500  may remain in place and used to attach a distractor (not shown) to the first cuneiform  210  and the first metatarsal  230 , such that the distractor can temporarily widen the space between the first cuneiform  210  and the first metatarsal  230  to allow for fenestration and/or other preparation of the cut surfaces of the first cuneiform  210  and the first metatarsal  230 . Once such preparation has been carried out, the remaining pins  500  may also be removed. 
     The resulting bleeding and/or prepared bone may readily grow together and fuse, upon abutment of the distal end of the first cuneiform  210  to the proximal end of the first metatarsal  230 , particularly with application of some compression across the juncture of the two bones. Since the positions and orientations of the first slot  350  and the second slot  352  were carefully selected to provide the proper correction, the first metatarsal  230  may be positioned to abut the first cuneiform  210 , resulting in reorientation of the first metatarsal  230  to a desired orientation, relative to the lateral direction  260  and the plantar direction  280  and/or the dorsal direction  290 . Further, the surgeon may optionally rotate the first metatarsal  230 , relative to the first cuneiform  210 , about an axis perpendicular to the cutting planes, if desired. 
       FIG. 6A  is a perspective view of the foot  200  of  FIG. 2 , after resection of the first cuneiform  210  and the first metatarsal  230 , removal of the cutting guide  300 , and placement of the first metatarsal  230  to abut the first cuneiform  210 . As shown, the distal end  250  of the first metatarsal  230  may now be positioned much closer to the second metatarsal  240 , in a more natural position. Further,  FIG. 6A  depicts a first proximal phalanx  600 , which may now be properly oriented generally parallel to the other phalanges (not shown), rather than pointing in the lateral direction  260 . If desired, further steps may be performed relative to the joint between the first metatarsal  230  and the first proximal phalanx  600  in order to keep them in the proper relative orientation. The distal end  250  may also have been shifted in the plantar direction  280  or in the dorsal direction  290  from the position of  FIG. 2 . Thus, the desired dual-plane correction of the orientation of the first metatarsal  230  may be complete. 
     The first metatarsal  230  may be secured to the first cuneiform  210 , at least until proper bone in-growth has occurred between the first cuneiform  210  and the first metatarsal  230 . In some embodiments, a bone plate (not shown) or other fastener (not shown) may be used to secure the first cuneiform  210  and the first metatarsal  230  together. Additional hardware (not shown) may be used to stabilize the position and/or orientation of the first proximal phalanx  600  relative to the first metatarsal  230 , if desired. The surgical wound may be closed, and the foot  200  may be allowed to heal with the bunion deformity corrected. 
       FIGS. 6B and 6C  are dorsal views of the foot  200 , before and after correction, respectively.  FIGS. 6B and 6C  illustrate the correction of the angulation of the first metatarsal  230 , by which the distal end  250  of the first metatarsal  230  is moved in the lateral direction  260 . In some embodiments, an implant  610  may be inserted in the space between the first metatarsal  230  and the first cuneiform  210  in order hold the first metatarsal  230  and the first cuneiform  210  together and/or facilitate bony fusion between the first metatarsal  230  and the first cuneiform  210 . 
     In some embodiments, the implant  610  may be patient-specific. For example, the implant  610  may have a cuneiform-facing side  620  that is shaped and/or sized to be secured to the adjoining, resected surface of the first cuneiform  210 , and a metatarsal-facing side  630  that is shaped and/or sized to be secured to the adjoining, resected surface of the first metatarsal  230 . As the resections made to the first metatarsal  230  and the first cuneiform  210  may both planar, the cuneiform-facing side  620  and/or the metatarsal-facing side  630  may also be planar. However, the cuneiform-facing side  620  and/or the metatarsal-facing side  630  may advantageously each be shaped to match the profile of the resected surface of the first cuneiform  210  and the first metatarsal  230 , respectively. 
     This shaping may be accomplished by custom-designing the implant  610  for the patient, using the same models (for example, from CT scans) of the first metatarsal  230  and the first cuneiform  210  that were used to generate the cutting guide  300 . Thus, the implant  610  may have a shape that provides secure attachment and/or fusion between the first metatarsal  230  and the first cuneiform  210  while avoiding proud edges or other protruding features that could otherwise interfere with surrounding tissues. 
     As indicated previously, the cutting guide  300  is one of many patient-specific instruments that may be used in connection with the method  100  and/or the method  120 . An alternative cutting guide suitable for use with the method  120  will be shown and described in connection with  FIGS. 7A, 7B, 7C, and 7D . 
       FIGS. 7A, 7B, 7C, and 7D  are top perspective, alternative top perspective, front elevation, and bottom perspective views, respectively, of a patient-specific cutting guide, or cutting guide  700 , according to one alternative embodiment. The cutting guide  700  may be used to correct a bunion deformity, such as that of the foot  200  of  FIG. 2 . Thus, the cutting guide  700  may also be designed to facilitate resection of the first cuneiform  210  and the first metatarsal  230  with planar cuts at the proper angles to provide dual-plane correction of the orientation of the first metatarsal  230 , thereby providing correction in the lateral direction  260  and in the plantar direction  280  or the dorsal direction  290 . 
     As shown, the cutting guide  700  may have a body  710  with a monolithic construction and the general shape of a rectangular prism. The cutting guide  700  may further have a joint alignment feature that helps align the body  710  with the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230 . The joint alignment feature may consist of a joint probe  720  that extends from the body  710  and has a blade-like shape. The body  710  may reside on the dorsal surfaces of the first cuneiform  210  and the first metatarsal  230 , while the joint probe  720  may protrude into the metatarsocuneiform joint between the first cuneiform  210  and the first metatarsal  230  to provide proper alignment of the body  710  with the metatarsocuneiform joint. Notably, the joint probe  720  may have surfaces that are not simply planar, but rather have some contouring by which the shape of the joint probe  720  is matched to the adjoining surfaces of the first cuneiform  210  and/or the first metatarsal  230 . Such contouring of the joint probe  720  may enable more precise alignment of the body  710  with the metatarsocuneiform joint. 
     The body  710  may have a bone facing side  730  that, upon attachment of the body  710  to the first cuneiform  210  and the first metatarsal  230 , is to face toward the first cuneiform  210  and the first metatarsal  230 . The body  710  may also have an outward-facing side  732  that, upon attachment of the body  710  to the first cuneiform  210  and the first metatarsal  230 , faces outward, away from the first cuneiform  210  and the first metatarsal  230 . Further, the body  710  may have one or more bone attachment features that facilitate attachment of the body  710  to the first cuneiform  210  and/or the first metatarsal  230 . Such bone attachment features may comprise any of a wide variety of holes, spikes, fastening devices, and/or the like. As embodied in  FIGS. 7A through 7D , the bone attachment features may take the form of holes  740  that extend from the bone facing side  330  to the outward-facing side  332  and/or one or more fixation devices. The holes  340  may be shaped to accommodate pins, K-wires, and/or other elongated bone fixation elements that can be anchored in the first cuneiform  210  and/or the first metatarsal  230  to keep the cutting guide  700  in place. As embodied in  FIGS. 7A through 7D , only one hole  340  may be present on each side of the body  710 . Thus, the body  710  may be secured to the first cuneiform  210  with only a single pin or K-wire (not shown) and to the first metatarsal  230  with only another single pin or K-wire (not shown). 
     The bone facing side  730  may be custom contoured to match the shapes of the first cuneiform  210  and/or the first metatarsal  230 . As embodied in  FIGS. 7A through 7D , the bone facing side  730  may have a cuneiform apposition portion  742  shaped to lie against the dorsal surface of the first cuneiform  210 , and a metatarsal apposition portion  744  shaped to lie against the dorsal surface of the first metatarsal  230 . As shown, the cuneiform apposition portion  742  may be contoured to match the contour of the dorsal surface of the first cuneiform  210  on which it is to rest, and the metatarsal apposition portion  744  may similarly be contoured to match the contour of the dorsal surface of the first metatarsal  230  on which it is to rest. Thus, the body  710  may have only one stable position and orientation relative to the first cuneiform  210  and the first metatarsal  230 . Alternatively, or in addition, the cuneiform apposition portion  742  may be contoured to match the contour of a surface that is between the dorsal surface and a medial or lateral surface and/or the surface includes at least a portion of the dorsal surface of the first cuneiform  210  on which it is to rest, and the metatarsal apposition portion  744  may similarly be contoured to match the contour of a surface that is between the dorsal surface and a medial or lateral surface and/or the surface includes at least a portion of the dorsal surface of the dorsal surface of the first metatarsal  230 . 
     In certain embodiments, the topography of the articular surfaces of a joint may not factor into the form and/or shape of the cuneiform apposition portion  742  and/or the metatarsal apposition portion  744  because those parts of the bones will be resected during the procedure. Alternatively, or in addition, the topography of the articular surfaces of a joint may be factored into the form and/or shape of the cuneiform apposition portion  742  and/or the metatarsal apposition portion  744  even though those parts of the bones will be resected during the procedure. 
     Like the cuneiform apposition portion  342  and the metatarsal apposition portion  344  of the cutting guide  300 , generation of the contours of the cuneiform apposition portion  742  and the metatarsal apposition portion  744  may be performed relative easily in various CAD programs through surface copy operations, Boolean operations, and/or the like. 
     The body  710  may further have guide features that guide a cutter to resect the first cuneiform  210  and the first metatarsal  230  in the manner needed to make the desired correction. For example, the guide features may be used to guide a planar cutting blade, an arcuate cutting blade, a drill or mill, and/or the like. 
     In the embodiment of  FIGS. 7A through 7D , the guide features may guide a reciprocating planar blade, such as that of a surgical bone saw, that forms planar cuts in the first cuneiform  210  and the first metatarsal  230 . Thus, the guide features may take the form of a first slot  750  and a second slot  752 , which may be positioned toward the center of the body  710 , on opposite sides of the joint probe  720 . Thus, upon proper positioning of the cutting guide  700 , the first slot  750  may be positioned over the first cuneiform  210  to facilitate resection of the first cuneiform  210 , while the second slot  752  may be positioned over the first metatarsal  230  to facilitate resection of the first metatarsal  230 . 
     In operation, the cutting guide  700  may be used in a manner similar to that of the cutting guide  300 . However, the cutting guide  700  may only be secured to each of the first cuneiform  210  and the first metatarsal  230  with a single pin or K-wire (not shown), as mentioned previously. Further, the cutting guide  700  is smaller than the cutting guide  300 . Thus, the cutting guide  700  may be placed through a smaller, less invasive incision. One advantage to patient-specific instrumentation may be that instruments may be made smaller, since they are not limited to certain sizes. Many known instruments come in discrete sizes, each of which is designed to accommodate a range of patient anatomic dimensions. Thus, for given patient anatomy, the instrument must be large enough to treat the anatomy at either end of its range. This typically requires the instrument to be oversized for many anatomic dimensions it is designed to treat. Notably, the cutting guide  700  is merely one compact example; other cutting guides may be made even smaller; in some embodiments, cutting guides may be made that have a smaller width between holes (e.g., holes  740  on the cutting guide  700 ). As long as the holes are sufficiently far apart to avoid interference of the pins  500  with the operation of the cutting blade, the cutting guide may function appropriately. Thus, Lapidus and other procedures may be accomplished through a very narrow incision through the use of patient-specific instrumentation. 
     Those of skill in the art will recognize that a wide variety of differently configured cutting guides may be used in conjunction with the method  120  set forth above. Further, a wide variety of patient-specific instruments may be used in connection with the method  100 , including but not limited to cutting guides, gages, implant positioning guides, joint distractors, joint compressors, soft tissue retractors, and the like. “Patient specific cutting guide” refers to a cutting guide designed, engineered, and/or fabricated for use with a specific patient. In one aspect, a patient specific cutting guide is unique to a single patient and may include features unique to the patient such as a surface contour or other features. 
     Furthermore, patient-specific cutting guides may be used for various other procedures on the foot, or on other bones of the musculoskeletal system. Patient-specific cutting guides may be used for various procedures involving osteotomy, including but not limited to arthroplasty, fusion, and deformity correction procedures. According to one example, patient-specific cutting guides similar to the cutting guide  300  and the cutting guide  700  may be used for the metatarsophalangeal (“MTP”) joint. A method similar to the method  100  may be employed. 
     In some embodiments, one or more articulating surfaces of a joint may be replaced and/or resurfaced. For example, for the MTP joint, a patient-specific cutting guide may be used to determine the angles of cuts on the distal metatarsal or the proximal phalanx in preparation for replacement or resurfacing of the metatarsal head and/or the proximal phalangeal base. Implants for either the metatarsal or the phalanx may be customized to match the patient&#39;s original anatomy, such as the curvature of the MTP joint. In other embodiments, an MTP joint may be fused through the use of patient-specific cutting guides. Patient-specific cutting guides may be used to treat (for example, via fusion, resurfacing, and/or arthroplasty) any joint in the body, using methods similar to the method  100 . 
     According to other examples, patient-specific cutting guides may be used to carry out an Evans calcaneal osteotomy and/or a medializing calcaneal osteotomy. Patient-specific instruments will be shown and described in connection with  FIGS. 8A through 11 , in relation to an Evans calcaneal osteotomy, and a medializing calcaneal osteotomy. 
     As used herein, “osteotomy procedure” or “surgical osteotomy” refers to a surgical operation in which one or more bones are cut to shorten or lengthen them or to change their alignment. The procedure can include removing one or more portions of bone and/or adding one or more portions of bone or bone substitutes. (Search “osteotomy” on Wikipedia.com Feb. 3, 22, 2021. CC-BY-SA 3.0 Modified. Accessed Feb. 15, 2022.) As used herein, “patient specific osteotomy procedure” refers to an osteotomy procedure that has been adjusted, tailored, modified, or configured to specifically address the anatomy, physiology, condition, abnormalities, needs, or desires of a particular patient. In certain aspects, one patient specific osteotomy procedure may be useable in connection with only one patient. In other aspects, one patient specific osteotomy procedure may be useable with a number of patients having a particular class of characteristics. 
       FIGS. 8A, 8B, and 8C  are dorsal pre-operative, dorsal post-operative, and lateral post-operative views, respectively, of a foot treated with an Evans calcaneal osteotomy, according to one embodiment. Outward rotation of the foot may occur in patients with flatfoot. An Evans or lateral column lengthening procedure is sometimes performed for these patients. An incision is made on the outside of the foot, and the front half of the heel bone is cut. A bone wedge (typically either titanium or a bone-based graft) is then placed into the cut area of the heel bone. This wedge helps to “lengthen” the heel bone and rotate the foot back into its correct position. The wedge is usually kept in place using screws or a surgical staple. 
       FIGS. 9A and 9B  are dorsal post-operative and lateral post-operative views, respectively, of a foot treated with a medializing calcaneal osteotomy, according to one embodiment. A medializing calcaneal osteotomy (heel slide) procedure is often used when the calcaneus (heel bone) has shifted out from underneath the leg. An incision is made on the outside of the heel, and the back half of the heel bone is cut and slid back underneath the leg. The heel is then fixed in place using metal screws or a plate. This also helps to reposition the Achilles tendon towards the center of the ankle/rearfoot. The medializing calcaneal osteotomy can be used in place of, or in addition to, an Evans calcaneal osteotomy. 
       FIG. 10  is a rear, perspective view of the foot  200  of  FIG. 2 , after performance of an Evans calcaneal osteotomy and a medializing calcaneal osteotomy with patient-specific instruments and/or implants, according to one embodiment. The foot  200  may have a calcaneus  1000  and a talus  1010 , in addition to the metacarpals  1020  and cuneiforms  1030  depicted in  FIG. 2 . Pursuant to the Evans calcaneal osteotomy, an anterior portion of the calcaneus  1000  may be cut along the medial-lateral direction to separate a first bone segment  1040  of the calcaneus  1000  from a second bone segment  1042  of the calcaneus  1000 . The second bone segment  1042  may be reoriented medially, relative to the first bone segment  1040 , such that a heel  1050  of the calcaneus  1000  is moved medially, simulating a natural, healthy arch in the foot  200 . 
     The cut between the first bone segment  1040  and the second bone segment  1042  may be carried out virtually (for example, in CAD) on a model of the calcaneus  1000  obtained from a CT scan or other imaging of the patient&#39;s foot. Thus, the optimal realignment of the posterior end of the calcaneus  1000  can be obtained. If desired, a patient-specific cutting guide, or cutting guide  1043 , may be generated in order to facilitate resection of the calcaneus  1000 . 
     As shown, the cutting guide  1043  may have a first end  1044  and a second end  1045 , each of which has a bone attachment feature  1046 . The bone attachment features  1046  may be used to secure the first end  1044  and the second end  1045  to the first bone segment  1040  and the second bone segment  1042 , respectively. The first end  1044  may have a first bone engagement surface  1047  that is shaped to match a corresponding contour on the first bone segment  1040 , and the second end  1045  may have a second bone engagement surface  1048  that is shaped to match a corresponding contour on the second bone segment  1042 . Thus, the cutting guide  1043  may naturally lie flush with the surface of the calcaneus  1000 , in the optimal position on the calcaneus  1000  to facilitate resection of the calcaneus  1000  to divide the first bone segment  1040  from the second bone segment  1042 . The cutting guide  1043  may have a guide feature  1049 , such as a slot, that can be used to guide a cutter to form a single cut between the first bone segment  1040  and the second bone segment  1042 . 
     After the cut has been made to split the calcaneus  1000  into the first bone segment  1040  and the second bone segment  1042 , the surgeon may angle the second bone segment  1042  relative to the first bone segment  1040  in the predetermined (previously modeled) relative orientation. This reorientation between the first bone segment  1040  and the second bone segment  1042  may leave a wedge-shaped gap between the first bone segment  1040  and the second bone segment  1042 . In order to maintain the desired relative orientation, an implant  1060  with a wedge shape may be inserted into the gap and secured to the first bone segment  1040  and the second bone segment  1042 . The implant  1060  may be fabricated specifically for the patient, since the precise angulation and position of the realignment may also be patient specific. As shown, the implant  1060  may have exterior surfaces that are contoured to match the contours of the adjoining portions of the first bone segment  1040  and the second bone segment  1042 . Thus, the implant  1060  may provide secure fixation, while not protrude beyond the adjoining surfaces of the first bone segment  1040  and the second bone segment  1042 . Thus, the implant  1060  may be devoid of proud edges or other protrusions that could otherwise interfere with motion between the calcaneus  1000  and the talus  1010 , or with surrounding soft tissues, thus interfering with the patient&#39;s post-operative gait. “Soft tissue” refers to tissue of a patient (i.e., human or animal). Examples of soft tissue include but are not limited to skin, ligament, tendon, fascia, fat muscle, fibrous tissue, blood vessels, lymph vessels, brain tissue, and/or nerves. 
     The implant  1060  may be made of any biocompatible material, including but not limited to Titanium and alloys thereof, stainless steel, PEEK, and/or the like. The implant  1060  may be formed by any method known in the art, including but not limited to forging, casting, milling, additive manufacturing, and/or the like. In some embodiments, the implant  1060  may have an interior void that can be filled with bone graft or other material designed to promote boney in-growth between the cut surfaces of the first bone segment  1040  and the second bone segment  1042 . In alternative embodiments, the implant  1060  may have a mesh and/or lattice structure that facilitates such boney in-growth, which structure may be formed via additive manufacturing. 
     As mentioned previously, a medializing calcaneal osteotomy may optionally be performed in addition to or in place of the Evans calcaneal osteotomy. As shown, the heel  1050  may be cut from the remainder of the second bone segment  1042  and may be displaced medially. This displacement may also help to restore normal gait and tendon function in the foot  200 , particularly when coupled with the Evans calcaneal osteotomy. The proper displacement of the heel  1050  relative to the remainder of the second bone segment  1042  may be determined based on analysis of the CAD models from scans of the foot  200 . If desired, the model of the calcaneus  1000  may be divided and manipulated in CAD to simulate the repositioning of the heel  1050  pursuant to the medializing calcaneal osteotomy. Thus, the alignment of the heel  1050  relative to the remainder of the foot  200  can easily be assessed and optimized prior to surgery. 
     Such preoperative alignment and planning may be particularly useful where multiple procedures, such as the Evans calcaneal osteotomy and the medializing calcaneal osteotomy, are combined for a single patient. Without such planning, it may be difficult to properly assess the effect of the combined procedures on the patient&#39;s anatomy. For example, the effect of the Evans calcaneal osteotomy, and that of the medializing calcaneal osteotomy, is to shift the heel  1050  medially. The combined shift may be difficult to assess in the operating room but may be much more easily and accurately gauged via manipulation of the modeled anatomy. 
     In some embodiments, one or more additional procedures may be carried out, in addition to or in the alternative to those of  FIG. 9 . For example, in addition to or in the alternative to the Evans calcaneal osteotomy and the medializing calcaneal osteotomy, a cotton osteotomy (medial cuneiform opening wedge osteotomy) and/or a first metatarsal midfoot osteotomy may be performed. Patient-specific cutting guides may be designed, fabricated, and surgically used to facilitate any of these procedures through the presence of bone engagement surfaces that are shaped to rest on the particular bony surfaces adjacent to the osteotomy. 
     As in the case of the Evans calcaneal osteotomy, a custom cutting guide, or cutting guide  1053 , may be generated to help the surgeon obtain the correction that was previously modeled and/or planned using the computer models of the foot  200 . The cutting guide  1053  may have a structure and function similar to that of the cutting guide  1043  used for the Evans calcaneal osteotomy. Such a cutting guide may have contoured surfaces that match the contours of the adjoining boney surfaces of the remainder of the second bone segment  1042  and/or the heel  1050 . 
     More specifically, the cutting guide  1053  may have a first end  1054  and a second end  1055 , each of which has a bone attachment feature  1056 . The bone attachment features  1056  may be used to secure the first end  1054  and the second end  1055  to the second bone segment  1042  and the heel  1050 , respectively. The first end  1054  may have a first bone engagement surface  1057  that is shaped to match a corresponding contour on the second bone segment  1042 , and the second end  1055  may have a second bone engagement surface  1058  that is shaped to match a corresponding contour on the heel  1050 . Thus, the cutting guide  1053  may naturally lie flush with the surface of the calcaneus  1000 , in the optimal position on the calcaneus  1000  to facilitate resection of the calcaneus  1000  to divide the second bone segment  1042  from the heel  1050 . The cutting guide  1053  may have a guide feature  1059 , such as a slot, that can be used to guide a cutter to form a single cut between the second bone segment  1042  and the heel  1050 . 
     In order to maintain the heel  1050  in the proper position relative to the remainder of the second bone segment  1042 , a bone plate  1070  may be secured to the heel  1050  and to the remainder of the second bone segment  1042 . The bone plate  1070  may include a first end  1080  secured to the remainder of the second bone segment  1042 , a second end  1082  secured to the heel  1050 , and an intermediate portion  1084  that extends from the first end  1080  to the second end  1082 , and provides the desired medial shift between the first end  1080  and the second end  1082 . The first end  1080  and the second end  1082  may be secured to the remainder of the second bone segment  1042  and to the heel  1050 , respectively, through the use of screws  1090 . 
     Like the implant  1060 , the bone plate  1070  may be made of any known biocompatible material, through the use of any manufacturing process known in the art. In some embodiments, the bone plate  1070  may also be fabricated specifically for the foot  200 , enabling the bone plate  1070  to precisely maintain the desired level of correction. When made specifically for the foot  200  in combination with each other, the implant  1060  and the bone plate  1070  may provide a highly predictable, precise, and customizable level of correction of the flat foot deformity. 
       FIG. 11  is a perspective view of the implant  1060 , in isolation. As shown, the implant  1060  may have a first bone-facing surface  1100  that is generally flat and shaped to match the cut surface of the first bone segment  1040 . The first bone-facing surface  1100  is shown in  FIG. 11  with a smooth shape; however, in alternative embodiments, the first bone-facing surface  1100  may be roughened and/or may have teeth, spikes, ridges, and/or other features intended to penetrate the first bone segment  1040  in order to provide for more secure engagement of the implant  1060  with the first bone segment  1040 . Similarly, the implant  1060  may have a second bone-facing surface  1110  (not visible) that is also generally flat and shaped to match the cut surface of the second bone segment  1042 . Like the first bone-facing surface  1100 , the second bone-facing surface  1110  may be roughened or have protruding features that strengthen engagement of the implant  1060  with the second bone segment  1042 . If desired, the implant  1060  may be further held in place through the use of bone screws, cement, one or more bone plates, and/or other features known in the art to secure an implant to bone. 
     The edges of the first bone-facing surface  1100  and the second bone-facing surface  1110  may be shaped to line up with the edges of the cut surfaces of the first bone segment  1040  and the second bone segment  1042 , respectively. The implant  1060  may also have a contoured surface  1120  that extends between the edges of the first bone-facing surface  1100  and the second bone-facing surface  1110 . The contoured surface  1120  may also be contoured to match the contours of the adjoining portions of the first bone segment  1040  and the second bone segment  1042 . Thus, the contoured surface  1120  may provide a continuous surface, devoid of protrusions, that extends between the adjoining surfaces of the first bone segment  1040  and the second bone segment  1042 . 
     A threaded hole  1130  may optionally be provided in the contoured surface  1120 . The threaded hole  1130  may be used to secure the implant  1060  to an insertion instrument, a positioning instrument, and/or a removal instrument. The threaded hole  1130  may be formed in a recess  1140  in the contoured surface  1120  so that the threaded hole  1130  can have the desired orientation, without affecting the shape of the contoured surface  1120  more than necessary. Of course, many other features may be used to secure an instrument to the implant  1060 , including various clips, clamps, fasteners, and interfacing features, as known in the art. 
     The present disclosure is not limited to cutting guides or extremity procedures. In some embodiments, patient-specific instrumentation may be used to correct a wide variety of bone conditions. Such conditions include, but are not limited to, any angular deformities from within one bone segment in either the lower or upper extremities (for example, tibial deformities, calcaneal deformities, femoral deformities, and radial deformities). The present disclosure may also be used to treat an interface between two bone segments (for example, the ankle joint, metatarsal cuneiform joint, lisfranc&#39;s joint, complex charcot deformity, wrist joint, knee joint, etc.). As one example, an angular deformity or segmental malalignment in the forefoot may be treated, such as is found at the metatarsal cuneiform level, the midfoot level such as the navicular cuneiform junction, hindfoot at the calcaneal cubiod or subtalar joint or at the ankle between the tibia and talar junction. Additionally, patient-specific instruments could be used in the proximal leg between two bone segments or in the upper extremity such as found at the wrist or metacarpal levels. 
       FIGS. 12A, 12B, 12C, 12D, 12E, 12F, 12G, and 12H  are top perspective, top, bottom, front elevation, rear elevation, right, left, and alternative top perspective, respectively, of a patient-specific cutting guide, or cutting guide  1200 , according to one alternative embodiment. 
     The cutting guide  1200  may be designed to facilitate resection of a first cuneiform and a first metatarsal with planar cuts at the proper angles to provide dual-plane correction of the orientation of the first metatarsal, thereby providing correction in a lateral direction and in a plantar direction or a dorsal direction. 
     As shown, the cutting guide  1200  may have a body  1210  with a monolithic construction and the general shape of a rectangular prism. The body  1210  may reside on the dorsal surfaces of the first cuneiform and the first metatarsal to provide proper alignment of the body  1210  with the metatarsocuneiform joint. 
     Further, the body  1210  may have one or more bone attachment features that facilitate attachment of the body  1210  to the first cuneiform and/or the first metatarsal. Such bone attachment features may comprise any of a wide variety of holes, spikes, fastening devices, and/or the like. As embodied in  FIGS. 12A through 12H , the bone attachment features may take the form of holes  1240  that extend from a bone facing side  1230  to the outward-facing side  1232  and/or one or more fixation devices. The holes  1240  may be shaped to accommodate pins, K-wires, and/or other elongated bone fixation elements that can be anchored in the first cuneiform and/or the first metatarsal to keep the cutting guide  1200  in place. 
     The bone facing side  1230  may be custom contoured to match the shapes of the first cuneiform and/or the first metatarsal. As embodied in  FIGS. 12A through 12F , the bone facing side  1230  may have a cuneiform apposition portion  1242  shaped to lie against the surface of the first cuneiform, and a metatarsal apposition portion  1244  shaped to lie against the surface of the first metatarsal. As shown, the cuneiform apposition portion  1242  may be contoured to match the contour of the surface of the first cuneiform on which it is to rest, and the metatarsal apposition portion  1244  may similarly be contoured to match the contour of the surface of the first metatarsal on which it is to rest. Thus, the body  1210  may have only one stable position and orientation relative to the first cuneiform and the first metatarsal. 
     The body  1210  may further have guide features that guide a cutter to resect the first cuneiform and the first metatarsal in the manner needed to make the desired correction. For example, the guide features may be used to guide a planar cutting blade, an arcuate cutting blade, a drill or mill, a burr, and/or the like. 
     In the embodiment of  FIGS. 12A through 12F , the guide features may guide a reciprocating planar blade, such as that of a surgical bone saw, that forms planar cuts in the first cuneiform and the first metatarsal. Thus, the guide features may take the form of a first slot  1250  and a second slot  1252 , which may be positioned toward the center of the body  1210 . Thus, upon proper positioning of the cutting guide  1200 , the first slot  1250  may be positioned over the first cuneiform to facilitate resection of the first cuneiform, while the second slot  1252  may be positioned over the first metatarsal to facilitate resection of the first metatarsal. 
     In alternative embodiments, a guide feature may be designed to guide a different type of cutter, such as a drill, mill, or side-cutting burr. In such embodiments, the guide feature may not be a slot, but may instead be a translatable or rotatable cutter retainer that guides translation and/or rotation of the cutter relative to the bone. 
     Returning to  FIGS. 12A through 12H , the body  1210  may further have features that facilitate desired translation and orientation of the first metatarsal in order to fuse or join the first cuneiform and the first metatarsal to complete the procedure. For example, in the illustrated embodiment, the cutting guide  1200  may include two alignment features  1260   a  and  1260   b.    
     In the embodiment of  FIG. 12A , one alignment feature  1260   a  is in the lower right-hand side of the body  1210 , the distal side of the body, and the other alignment feature  1260   b  is on a proximal side of the body  1210 . The two alignment features  1260   a  and  1260   b  may be separate features, or certain features such as one or more attachment features may serve a dual purpose as both an attachment feature and as an alignment feature. For example, in the embodiment of  FIG. 12A , alignment feature  1260   b  may use the same structure as the bone attachment features and may take the form of holes  1240  that extend from a bone facing side  1230  to the outward-facing side  1232  and/or one or more fixation devices. 
     Referring to  FIG. 12H , in certain embodiments, the cutting guide  1200  may include a detachable connector  1270  that couples an alignment feature  1260   a ,  1260   b  to the body  1210 . The detachable connector  1270  may connect or couple the alignment feature  1260   a  to the body  1210  and/or the alignment feature  1260   b  to the body  1210 . In one embodiment, the detachable connector  1270  may comprise a breakaway structure designed, engineered, and fabricated to securely connect an alignment feature  1260   a ,  1260   b  to the body  1210  for one part of a procedure and to readily separate or breakaway from the body  1210  when a breaker tool  1271  (See  FIG. 14 ) is used to activate the breakaway function or feature. 
     In one embodiment, the detachable connector  1270  may include one or more grooves  1272  between an alignment feature  1260   a  and the body  1210 . The groove  1272  is an opening between the alignment feature  1260  and the body  1210 . Within a groove  1272  one or more bridges  1274  connect the alignment feature  1260  with the body  1210 . In one embodiment, the size, position, number, and configuration of one or more grooves  1272  and the corresponding one or more bridges  1274  is determined such that the alignment feature  1260  remains securely connected to the body  1210  for one part of the procedure and can be readily separated using a breaker tool  1271  for another part of the procedure. 
     In certain embodiments, the detachable connector  1270  may include one or more receivers  1276 . The receiver  1276  is sized, configured, and positioned to accept an end of the breaker tool  1271  such that insertion of the end of the breaker tool  1271  breaks one or more bridges  1274  and thus separates the alignment feature  1260  from the body  1210 . The receiver  1276  may have any cross-section shape including circular, elliptical, square, rectangular, or the like. 
     In one embodiment, the alignment feature  1260 , such as alignment feature  1260   a , can include one or more bone attachment features that may take the form of holes  1278  that extend from a bone facing side  1230  to the outward-facing side  1232  and/or one or more fixation devices. In certain embodiments, a pair of parallel holes  1278  form a guide for pins  1280  (See  FIG. 13 ) as part of a bone attachment feature. Advantageously, the holes  1278  may be angled with respect to a bone such as the first metatarsal. The angle for the holes  1278  may be customized based on the patient and the amount of adjustment desired for the first metatarsal. 
       FIG. 13  illustrates a perspective view of a first cuneiform  210  and first metatarsal  230  with one embodiment of a cutting guide  1300  secured to the two bones. The cutting guide  1300  includes pins  1280  in the holes  1240  to secure the cutting guide  1300  to the bones. (Pins  1280  for hole  1240   a  and hole  1240   b  and hole  1240   c  are omitted to facilitate certain disclosure.) 
       FIG. 13  illustrates that in one embodiment, the holes  1240  of each bone attachment feature can be parallel to each other such that pins  1280  in the holes  1240  are parallel to each other. Red line A illustrates that the holes  1240   a ,  1240   b  are aligned perpendicular to a resection cut that has been made on the first cuneiform  210  through slot  1350 . Pins  1280  in holes  1240   a,b  may be referred to as cuneiform pins and these parallel cuneiform pins form a line (red line A) perpendicular to a cut plane in the first cuneiform  210 . Red line B illustrates that the holes and corresponding parallel pins  1281  (which may be referred to as metatarsal pins) may form a line perpendicular to a cut plane in the first metatarsal  230 . The metatarsal pins  1281  are aligned perpendicular to a resection cut (also referred to as a MET cut) that has been made on the first metatarsal  230  through slot  1352 . 
       FIG. 14  illustrates a perspective view of a first cuneiform  210  and first metatarsal  230  with one embodiment of a cutting guide  1400  secured to the two bones. The cutting guide  1400  includes pins  1280   a - f  in the holes  1240  of bone attachment features and the holes  1278  of the alignment features  1260 , such as alignment feature  1260   a.    
     At this stage in a surgical procedure, the cutting guide  1400  is placed on the first cuneiform  210  and the first metatarsal  230  and pins  1280   a - d  are connected to the bones through the respective holes  1240 . Next, a surgeon uses the guide features of the cutting guide  1400  to reset the first cuneiform  210  and the first metatarsal  230 . Then, a surgeon may insert pins  1280   e,f  into holes  1278  of the alignment feature  1260   a . Alternatively, in another embodiment, a surgeon may insert pins  1280   e,f  into holes  1278  of the alignment feature  1260   a  before resecting the first cuneiform  210  and/or first metatarsal  230 . 
     In one embodiment, a surgeon may next remove the pins  1280   c,d . Alternatively, a surgeon may remove the pins  1280   c,d  after breaking the alignment feature  1260   a  away from the body  1210 , as described below. 
     Advantageously, with pins  1280   a,b  in place and pins  1280   e,f  in place the cutting guide  1400  has been fabricated and custom engineered such that bringing pins  1280   a,b  and pins  1280   e,f  in parallel alignment with each other will align the resected surfaces of the first cuneiform  210  and first metatarsal  230  to accomplish a desired translation, rotation, and/or orientation of the first metatarsal  230  relative to the first cuneiform  210  for the procedure. In other words, the alignment features  1260   a,b  are placed and configured in the cutting guide  1400  such that bringing pins  1280   a,b  and pins  1280   e,f  in parallel alignment provides a desired frontal plane correction required to bring sesamoids into proper alignment, based on an evaluation of a pre-operative CAD model. Because the cutting guide  1400  is custom fabricated for a particular patient, the alignment features  1260   a,b  are positioned such that aligning these alignment features  1260   a  after the resection will provide a desired frontal plane rotation that is unique to each patient and built into, designed into, the cutting guide  1400 . The detachable connector  1270  connecting the alignment feature  1260   a  to the body  1210  is what enables a single cutting guide  1200  to become two during a procedure and provide a custom translation and rotation of a first metatarsal  230  that can be unique for each patient. 
     Furthermore, fabricating a cutting guide that is customized to a particular patient and a specific desired correction/adjustment enables correction of a variety of angular deformities (in all 3 planes) of the midfoot or hind foot and ankle where an osteotomy could be used. The alignment features  1260  disclosed in this solution and the corresponding pins formed within a cutting guide that may also include a detachable connector  1270  enable correction procedures for a variety of angular deformities (in all 3 planes) of the midfoot or hind foot and ankle where an osteotomy could be used. For example, embodiments of the procedures and devices herein disclosed can be used to address cavus, and mid foot dislocations, fracture malunion, metatarsal adductus, etc. They can also be used in preparation for joint resurfacing procedures of the foot and ankle to optimize placement of an arthroplasty implant. 
     Next, a breaker tool  1271  can be used to separate the alignment feature  1260   a  from the body  1210 . In one embodiment, a breakertool  1271  can be a “T” shaped tool with a crosswise proximal handle, a shaft, and a distal end. A user may operate the breaker tool  1271  by placing the distal end in a receiver  1276  of one or more detachable connectors  1270 . Pressing and/or twisting the distal end into the receiver  1276  breaks one or more bridges  1274  and thus separates the alignment feature  1260   a . A user may insert the distal end into one or more receivers  1276  to separate the alignment feature  1260   a  from the body  1210 . 
     Next, with the alignment feature  1260   a  separated from the body  1210 , and pins  1280   c,d  removed, a user can remove the two parts of the cutting guide  1400  separately. Pins  1280   a,b  remain in the first cuneiform  210  and pins  1280   e,f  remain in the first metatarsal  230 . 
     Next, a parallel compressor/distractor  1500  such as the exemplary parallel compressor/distractor  1500  illustrated in  FIG. 15  is used to distract the first metatarsal  230  relative to the first cuneiform  210 . The user slides holes  1502   a,b  over pins  1280   a,b  and holes  1502   c,d  over pins  1280   e,f . This causes a desired rotation and translation of the first metatarsal  230  relative to the first cuneiform  210 . When a user places the parallel compressor/distractor  1500  on over these pins  1280   a,b,e,f  this forces the cut faces of the two bones to become parallel. Advantageously, the cut faces of the two bones can be forced to become parallel because the position, orientation, and angles of the holes  1278  and/or holes of either or both of the alignment feature  1260   a  and alignment feature  1260   b  can be predefined and customized for each patient when the cutting guide  1300  is fabricated. This alignment enables parallel compression of the two bones together using the parallel compressor/distractor  1500 . Parallel compression enables more effective compression of the two bones together. Next, the space between the resected surfaces of the first cuneiform  210  and the first metatarsal  230  is prepared for fusion. Then, the parallel compressor/distractor  1500  is activated such that the first cuneiform  210  and the first metatarsal  230  are fused together. The parallel compressor/distractor  1500  may include a first leg  1504  and a second leg  1506 . At one end of each leg  1504 / 1506 , the leg may include a toe  1508 / 1510  at its distal end. In one embodiment, the toes  1508 / 1510  are angled to point towards each other. The angled configuration of the legs  1504 / 1506  by way of the toes  1508 / 1510  may apply a torque force at the toes  1508 / 1510  which may further assist in pressing two bones connected to the parallel compressor/distractor  1500  together. 
     Referring to  FIG. 16 , in certain embodiments, a parallel compressor/distractor  1600  such as the exemplary parallel compressor/distractor  1600  having holes  1602  illustrated in  FIG. 16  can be used to distract the first metatarsal  230  relative to the first cuneiform  210 . The parallel compressor/distractor  1600  may also include a cross joint guide  1604 . The user may slide holes  1602   a,b  over pins  1280   a,b  and holes  1602   c,d  (not visible, obscured by holes  1606   a,b  which are aligned with holes  1602   c,d ) over pins  1280   e,f.    
     The cross joint guide  1604  may serve as a guide for cross joint fasteners or other kinds of implants or fixation devices that can be installed across a joint between the first cuneiform  210  and the first metatarsal  230 . In one embodiment, the cross joint guide  1604  may include one or more bone attachment features that may take the form of holes  1608  that extend from one side of the cross joint guide  1604  to the other side and/or one or more fixation devices. The holes  1608  may be used to connect a holding across the joint between the first cuneiform  210  and the first metatarsal  230  after compression. 
       FIG. 17  illustrates a flowchart diagram depicting a method  1700  for generating one or more patient specific instruments configured to correct a bone condition, according to one embodiment. Prior to steps of the method  1700 , a bone model (also referred to as CAD model above) is generated. The bone model may be generated using medical imaging of a patient&#39;s foot and may also be referred to as an anatomic model. The medical imaging image(s) may be used by computing devices to generate patient imaging data. The patient imaging data may be used to measure and account for orientation of one or more structures of a patient&#39;s anatomy. In certain embodiments, the patient imaging data may serve or be a part of anatomic data for a patient. 
     As used herein, “anatomic data” refers to data identified, used, collected, gathered, and/or generated in connection with an anatomy of a human or animal. Examples of anatomic data may include location data for structures, both independent, and those connected to other structures within a coordinate system. Anatomic data may also include data that labels or identifies one or more anatomical structures. Anatomic data can include volumetric data, material composition data, and/or the like. Anatomic data can be generated based on medical imaging data or measurements using a variety of instruments including monitors and/or sensors. Anatomic data can be gathered, measured, or collected from anatomical models and/or can be used to generate, manipulate, or modify anatomical models. 
     A bone model or anatomic model of a patient&#39;s body or body part(s) may be generated by computing devices that analyze medical imaging images. Structures of a patient&#39;s body can be determined using a process called segmentation. 
     As used herein, “segmentation” or “image segmentation” refers the process of partitioning an image into different meaningful segments. These segments may correspond to different tissue classes, organs, pathologies, bones, or other biologically relevant structures. Medical image segmentation accommodates imaging ambiguities such as by low contrast, noise, and other imaging ambiguities. 
     Certain computer vision techniques can be used or adapted for image segmentation. For example, the techniques and or algorithms for segmentation may include, but are not limited to: Atlas-Based Segmentation: For many applications, a clinical expert can manually label several images; segmenting unseen images is a matter of extrapolating from these manually labeled training images. Methods of this style are typically referred to as atlas-based segmentation methods. Parametric atlas methods typically combine these training images into a single atlas image, while nonparametric atlas methods typically use all of the training images separately. Atlas-based methods usually require the use of image registration in order to align the atlas image or images to a new, unseen image. 
     Image registration is a process of correctly aligning images; Shape-Based Segmentation: Many methods parametrize a template shape for a given structure, often relying on control points along the boundary. The entire shape is then deformed to match a new image. Two of the most common shape-based techniques are Active Shape Models and Active Appearance Models; Image-Based Segmentation: Some methods initiate a template and refine its shape according to the image data while minimizing integral error measures, like the Active contour model and its variations; Interactive Segmentation: Interactive methods are useful when clinicians can provide some information, such as a seed region or rough outline of the region to segment. An algorithm can then iteratively refine such a segmentation, with or without guidance from the clinician. Manual segmentation, using tools such as a paint brush to explicitly define the tissue class of each pixel, remains the gold standard for many imaging applications. Recently, principles from feedback control theory have been incorporated into segmentation, which give the user much greater flexibility and allow for the automatic correction of errors; Subjective surface Segmentation: This method is based on the idea of evolution of segmentation function which is governed by an advection-diffusion model. To segment an object, a segmentation seed is needed (that is the starting point that determines the approximate position of the object in the image). Consequently, an initial segmentation function is constructed. With the subjective surface method, the position of the seed is the main factor determining the form of this segmentation function; and Hybrid segmentation which is based on combination of methods. (Search “medical image computing” on Wikipedia.com Jun. 24, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 24, 2021.) 
     In one embodiment, the method  1700  begins after a bone model of a patient&#39;s body or body part(s) is generated. In a first step  1702 , the method  1700  may review the bone model and data associated with the bone model to determine anatomic data of a patient&#39;s foot. 
     After step  1702 , the method  1700  determine  1704  a deformity in the patient&#39;s anatomy using the anatomic data. In certain embodiments, the detection and/or identification of a deformity may employ advanced computer analysis, expert systems, machine learning, and/or automated/artificial intelligence. As used herein, “artificial intelligence” refers to intelligence demonstrated by machines, unlike the natural intelligence displayed by humans and animals, which involves consciousness and emotionality. The distinction between artificial intelligence and natural intelligence categories is often revealed by the acronym chosen. ‘Strong’ AI is usually labelled as artificial general intelligence (AGI) while attempts to emulate ‘natural’ intelligence have been called artificial biological intelligence (ABI). Leading AI textbooks define the field as the study of “intelligent agents”: any device that perceives its environment and takes actions that maximize its chance of achieving its goals. The term “artificial intelligence” can also be used to describe machines that mimic “cognitive” functions that humans associate with the human mind, such as “learning” and “problem solving”. (Search “artificial intelligence” on Wikipedia.com Jun. 25, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 25, 2021.) Various kinds of deformities may be identified, such as a bunion. The deformities determined may include congenital as well as those caused by injury or trauma. 
     Next, the method  1700  proceeds and a preliminary cutting guide model is provided  1706  from a repository of template cutting guide models. A preliminary cutting guide model is a model of a preliminary cutting guide. 
     As used herein, “preliminary cutting guide” refers to a guide configured, designed, and/or engineered to serve as a template, prototype, archetype, or starting point for creating, generating, or fabricating a patient specific cutting guide. In one aspect, the preliminary cutting guide may be used, as-is, without any further changes, modifications, or adjustments and thus become a patient specific cutting guide. In another aspect, the preliminary cutting guide may be modified, adjusted, or configured to more specifically address the goals, objectives, or needs of a patient or a surgeon and by way of the modifications become a patient specific cutting guide. The patient specific cutting guide can be used by a user, such as a surgeon, to guide making one or more resections of a structure, such as a bone for a procedure. Accordingly, a preliminary cutting guide model can be used to generate a patient specific cutting guide model. The patient specific cutting guide model may be used in a surgical procedure to address, correct, or mitigate effects of the identified deformity and may be used to generate a patient specific cutting guide that can be used in a surgical procedure for the patient. 
     In certain embodiments, the preliminary cutting guide model may be generated based on anatomic data and/or a bone model or a combination of these, and no model or predesigned structure, template, or prototype. Alternatively, or in addition, the preliminary cutting guide model may be, or may originate from, a template cutting guide model selected from a set of template cutting guide model. Each model in the set of template cutting guide models may include one or more cutting guide features positioned and/or sized and/or configured to fit for an average patient&#39;s foot. The template cutting guide model may subsequently be modified or revised by an automated process or manual process to generate the preliminary cutting guide model used in this disclosure. 
     As used herein, “template cutting guide” refers to a guide configured, designed, and/or engineered to serve as a template for creating, generating, or fabricating a patient specific cutting guide. In one aspect, the template cutting guide may be used, as-is, without any further changes, modifications, or adjustments and thus become a patient specific cutting guide. In another aspect, the template cutting guide may be modified, adjusted, or configured to more specifically address the goals, objectives, or needs of a patient or a surgeon and by way of the modifications become a patient specific cutting guide. The patient specific cutting guide can be used by a user, such as a surgeon, to guide making one or more resections of a structure, such as a bone for a procedure. Accordingly, a template cutting guide model can be used to generate a patient specific cutting guide model. The patient specific cutting guide model may be used in a surgical procedure to address, correct, or mitigate effects of the identified deformity and may be used to generate a patient specific cutting guide that can be used in a surgical procedure for the patient. 
     “Repository” refers to any data source or dataset that includes data or content. In one embodiment, a repository resides on a computing device. In another embodiment, a repository resides on a remote computing or remote storage device. A repository may comprise a file, a folder, a directory, a set of files, a set of folders, a set of directories, a database, an application, a software application, content of a text, content of an email, content of a calendar entry, and the like. A repository, in one embodiment, comprises unstructured data. A repository, in one embodiment, comprises structured data such as a table, an array, a queue, a look up table, a hash table, a heap, a stack, or the like. A repository may store data in any format including binary, text, encrypted, unencrypted, a proprietary format, or the like. 
     Next, the method  1700  may register  1708  the preliminary cutting guide model with one or more bones of the bone model. This step  1708  facilitates customization and modification of the preliminary cutting guide model to generate a patient specific cutting guide model from which a patient specific cutting guide can be generated. The registration step  1708  combines two models and/or patient imaging data and positions both models for use in one system and/or in one model. 
     As used herein, “registration” or “image registration” refers to a method, process, module, component, apparatus, and/or system that seeks to achieve precision in the alignment of two images. As used here, “image” may refer to either or both an image of a structure or object and another image or a model (e.g., a computer based model or a physical model, in either two dimensions or three dimensions). In the simplest case of image registration, two images are aligned. One image may serve as the target image and the other as a source image; the source image is transformed, positioned, realigned, and/or modified to match the target image. An optimization procedure may be applied that updates the transformation of the source image based on a similarity value that evaluates the current quality of the alignment. An iterative procedure of optimization may be repeated until a (local) optimum is found. An example is the registration of CT and PET images to combine structural and metabolic information. Image registration can be used in a variety of medical applications: Studying temporal changes; Longitudinal studies may acquire images over several months or years to study long-term processes, such as disease progression. Time series correspond to images acquired within the same session (seconds or minutes). Time series images can be used to study cognitive processes, heart deformations and respiration; Combining complementary information from different imaging modalities. One example may be the fusion of anatomical and functional information. 
     Since the size and shape of structures vary across modalities, evaluating the alignment quality can be more challenging. Thus, similarity measures such as mutual information may be used; Characterizing a population of subjects. In contrast to intra-subject registration, a one-to-one mapping may not exist between subjects, depending on the structural variability of the organ of interest. Inter-subject registration may be used for atlas construction in computational anatomy. Here, the objective may be to statistically model the anatomy of organs across subjects; Computer-assisted surgery: in computer-assisted surgery pre-operative images such as CT or MRI may be registered to intra-operative images or tracking systems to facilitate image guidance or navigation. There may be several considerations made when performing image registration: The transformation model. Common choices are rigid, affine, and deformable transformation models. B-spline and thin plate spline models are commonly used for parameterized transformation fields. Non-parametric or dense deformation fields carry a displacement vector at every grid location; this may use additional regularization constraints. A specific class of deformation fields are diffeomorphisms, which are invertible transformations with a smooth inverse; The similarity metric. A distance or similarity function is used to quantify the registration quality. This similarity can be calculated either on the original images or on features extracted from the images. Common similarity measures are sum of squared distances (SSD), correlation coefficient, and mutual information. The choice of similarity measure depends on whether the images are from the same modality; the acquisition noise can also play a role in this decision. For example, SSD may be the optimal similarity measure for images of the same modality with Gaussian noise. However, the image statistics in ultrasound may be significantly different from Gaussian noise, leading to the introduction of ultrasound specific similarity measures. 
     Multi-modal registration may use a more sophisticated similarity measure; alternatively, a different image representation can be used, such as structural representations or registering adjacent anatomy; The optimization procedure. Either continuous or discrete optimization is performed. For continuous optimization, gradient-based optimization techniques are applied to improve the convergence speed. (Search “medical image computing” on Wikipedia.com Jun. 24, 2021. CC-BY-SA 3.0 Modified. Accessed Jun. 25, 2021.) 
     Next, the method  1700  may design  1710  a patient specific cutting guide model based on the preliminary cutting guide model. The design step  1710  may be completely automated or may optionally permit a user to make changes to a preliminary cutting guide model or partially completed patient specific cutting guide model before the patient specific cutting guide model is complete. A preliminary cutting guide model and patient specific cutting guide model are two examples of an instrument model. As used herein, “instrument model” refers to a model, either physical or digital, that represents an instrument, tool, apparatus, or device. Examples, of an instrument model can include a cutting guide model, a patient specific cutting guide model, and the like. In one embodiment, a patient specific cutting guide and a patient specific cutting guide model may be unique to a particular patient and that patient&#39;s anatomy and/or condition. 
     The method  1700  may conclude by a step  1712  in which patient specific cutting guide may be manufactured based on the patient specific cutting guide model. Various manufacturing tools, devices, systems, and/or techniques can be used to manufacture the patient specific cutting guide. As used herein, “manufacturing tool” or “fabrication tool” refers to a manufacturing or fabrication process, tool, system, or apparatus which creates an object, device, apparatus, feature, or component using one or more source materials. A manufacturing tool or fabrication tool can use a variety of manufacturing processes, including but not limited to additive manufacturing, subtractive manufacturing, forging, casting, and the like. The manufacturing tool can use a variety of materials including polymers, thermoplastics, metals, biocompatible materials, biodegradable materials, ceramics, biochemicals, and the like. A manufacturing tool may be operated manually by an operator, automatically using a computer numerical controller (CNC), or a combination of these techniques. 
       FIG. 18  illustrates an exemplary system  1800  configured to generate one or more patient specific instruments configured to correct a bone condition, according to one embodiment. “Bone condition” refers to any of a variety of conditions of bones of a patient. Bone conditions may be caused by or result from deformities, misalignment, malrotation, fractures, joint failure, and/or the like. A bone condition includes, but is not limited to, any angular deformities of one or more bone segments in either the lower or upper extremities (for example, tibial deformities, calcaneal deformities, femoral deformities, and radial deformities). “Malrotation” refers to a condition in which a part, typically a part of a patient&#39;s body has rotated from a normal position to an unnormal or uncommon position. The system  1800  may include an apparatus  1802  configured to accept, review, receive or reference a bone model  1804  and provide a patient specific cutting guide  1806 . In one embodiment, the apparatus  1802  is a computing device. In another embodiment, the apparatus  1802  may be a combination of computing devices and/or software components or a single software component such as a software application. 
     The apparatus  1802  may include a determination module  1810 , a deformity module  1820 , a provision module  1830 , a registration module  1840 , a design module  1850 , and a manufacturing module  1860 . Each of which may be implemented in one or more of software, hardware, or a combination of hardware and software. 
     The determination module  1810  determines anatomic data  1812  from a bone model  1804 . In certain embodiments, the system  1800  may not include a determination module  1810  if the anatomic data is available directly from the bone model  1804 . In certain embodiments, the anatomic data for a bone model  1804  may include data that identifies each anatomic structure within the bone model  1804  and attributes about the anatomic structure. For example, the anatomic data may include measurements of the length, width, height, and density of each bone in the bone model. Furthermore, the anatomic data may include position information that identifies where each structure, such as a bone is in the bone model  1804  relative to other structures, including bones. The anatomic data may be in any suitable format and may be stored separately or together with data that defines the bone model  1804 . 
     In one embodiment, the determination module  1810  may use advanced computer analysis such as image segmentation to determine the anatomic data. Alternatively, or in addition the determination module  1810  may use software and/or systems that implement one or more artificial intelligence methods (e.g., machine learning and/or neural networks) for deriving, determining, or extrapolating, anatomic data from the bone model. In one embodiment, the determination module  1810  may perform an anatomic mapping of the bone model  1804  to determine each unique aspect of the intended osteotomy procedure and/or bone resection and/or bone translation. The anatomic mapping may be used to determine coordinates to be used for an osteotomy procedure, position and manner of resections to be performed either manually or automatically or using robotic surgical assistance, a width for bone cuts, an angle for bone cuts, a predetermined depth for bone cuts, dimensions and configurations for resection instruments such as saw blades, milling bit size and/or speed, saw blade depth markers, and/or instructions for automatic or robotic resection operations. 
     The deformity module  1820  determines or identifies one or more deformities or other anomalies based on the anatomic data  1812 . The deformity may include a deformity between two bones of a patient&#39;s foot as represented in the bone model  1804 . In one embodiment, the deformity module  1820  may compare the anatomic data  1812  to a general model that is representative of most patient&#39;s anatomies and that does not have a deformity or anomaly. In one embodiment, if the anatomic data  1812  does not match the general model a deformity is determined. Various deformities may be detected including those that have well-known names for the condition and those that are unnamed. 
     The provision module  1830  is configured to provide a preliminary cutting guide model  1838 . The provision module  1830  may use a variety of methods to provide the preliminary cutting guide model. In one embodiment, the provision module  1830  may generate preliminary cutting guide model. In the same or an alternative embodiment, the provision module  1830  may select a template cutting guide model for an osteotomy procedure configured to correct the deformity identified by the deformity module  1820 . In one embodiment, the provision module  1830  may select a template cutting guide model from a set of template cutting guide models (e.g., a library, set, or repository of template cutting guide models). 
     The registration module  1840  registers the preliminary cutting guide model with one or more bones or other anatomical structures of the bone model  1804 . As explained above, registration is a process of combining medical imaging data, patient imaging data, and/or one or more models such that the preliminary cutting guide model can be used with the bone model  1804 . 
     The design module  1850  designs a patient specific cutting guide (or patient specific cutting guide model) based on the preliminary cutting guide model. The design operation of the design module  1850  may be completely automated, partially automated, or completely manual. A user may control how automated or manual the designing of the patient specific cutting guide (or patient specific cutting guide model) is. 
     The manufacturing module  1860  may manufacture a patient specific cutting guide  1806  using the preliminary cutting guide model. The manufacturing module  1860  may use a patient specific cutting guide model generated from the preliminary cutting guide model. The manufacturing module  1860  may provide the patient specific cutting guide model to one or more manufacturing tools and/or fabrication tool. The patient specific cutting guide model may be sent to the tools in any format such as an STL file or any other CAD modeling or CAM file or method for data exchange. In one embodiment, a user can adjust default parameters for the patient specific cutting guide such as types and/or thicknesses of materials, dimensions, and the like before the manufacturing module  1860  provides the patient specific cutting guide model to a manufacturing tool. 
       FIGS. 19A-19H  are top perspective, top perspective, bottom, front elevation, rear elevation, right, left, and alternative top perspective, respectively, of a patient-specific cutting guide, or cutting guide  1900 , according to one alternative embodiment. 
     The cutting guide  1900  may be designed to facilitate resection of a first cuneiform near a distal end and a first metatarsal near a proximal end with planar cuts at the proper angles to provide dual-plane correction of the orientation of the first metatarsal relative to the first cuneiform, thereby providing correction in a lateral direction, in a plantar direction, and/or a dorsal direction. 
     As shown, the cutting guide  1900  may have a body  1910  with a monolithic construction and the general shape of a rectangular prism. As used herein, a “body” refers to a main or central part of a structure. The body may serve as a structural component to connect, interconnect, surround, enclose, and/or protect one or more other structural components. A body may be made from a variety of materials including, but not limited to, metal, plastic, ceramic, wood, fiberglass, acrylic, carbon, biocompatible materials, biodegradable materials or the like. A body may be formed of any biocompatible materials, including but not limited to biocompatible metals such as Titanium, Titanium alloys, stainless steel alloys, cobalt-chromium steel alloys, nickel-titanium alloys, shape memory alloys such as Nitinol, biocompatible ceramics, and biocompatible polymers such as Polyether ether ketone (PEEK) or a polylactide polymer (e.g. PLLA) and/or others. In one embodiment, a body may include a housing or frame or framework for a larger system, component, structure, or device. A body may include a modifier that identifies a particular function, location, orientation, operation, and/or a particular structure relating to the body. Examples of such modifiers applied to a body, include, but are not limited to, “inferior body,” “superior body,” “lateral body,” “medial body,” and the like. 
     The body  1910  includes a proximal side  1912 , a distal side  1914 , a medial side  1916 , a lateral side  1918 , a superior side  1920 , and an inferior side  1922 . In the illustrated embodiment, the body  1910  may also include a proximal arm  1930  that extends from the body  1910  and a distal arm  1940  that extends from the body  1910 . The proximal side  1912  is the side closest to the core of the patient when the cutting guide  1900  is in use. The distal side  1914  is the side furthest from the core of the patient when the cutting guide  1900  is in use. The medial side  1916  is the side facing medially when the cutting guide  1900  is in use. The lateral side  1918  is the side facing laterally when the cutting guide  1900  is in use. The superior side  1920  is the side facing up away from the bone(s) when the cutting guide  1900  is in use. The inferior side  1922  is the side facing down, facing, and/or contacting the bone(s) (e.g., contacting a surface of one or more bones) when the cutting guide  1900  is in use. 
     The inferior side  1922  may be custom contoured to match the shapes of one or more of the surfaces of the first cuneiform and/or the first metatarsal. In one embodiment, the inferior side  1922  may include a bone engagement surface  1924 . The bone engagement surface  1924  can be shaped to match a first surface of a first bone and a second surface of a second bone of a joint. 
     As used herein, “bone engagement surface” refers to a surface of an object, instrument, or apparatus, such as an implant that is oriented toward or faces one or more bones of a patient. In one aspect, the bone engagement surface may abut, touch, or contact a surface of a bone. In another aspect, the bone engagement surface or parts of the bone engagement surface may be close to, but not abut, touch, or contact a surface of the bone. In certain aspects, the bone engagement surface can be configured to engage with a surface of one or more bones. Such a bone engagement surface may include projections and recesses that correspond to and match projections and recesses of the one or more bone surfaces. 
     “Joint” or “Articulation” refers to the connection made between bones in a human or animal body which link the skeletal system to form a functional whole. Joints may be biomechanically classified as a simple joint, a compound joint, or a complex joint. Joints may be classified anatomically into groups such as joints of hand, elbow joints, wrist joints, axillary joints, sternoclavicular joints, vertebral articulations, temporomandibular joints, sacroiliac joints, hip joints, knee joints, articulations of foot, and the like. (Search “joint” on Wikipedia.com Dec. 19, 2021. CC-BY-SA 3.0 Modified. Accessed Jan. 20, 2022.) 
     In one example, the bone engagement surface  1924  can be shaped such that the bone engagement surface  1924  matches a surface of a cuneiform bone and a surface of a metatarsal bone of a tarsometatarsal (“TMT”) joint. The bone engagement surface  1924  can be so shaped because it is fabricated from a bone model of the patient&#39;s bones. The body  1910  is configured, designed, and/or fabricated to seat transverse to a joint (e.g., a TMT joint) with the bone engagement surface  1924  engaging a first surface of a first bone and a second surface of a second bone. 
     In one embodiment, the body  1910  is configured to reside on the dorsal surfaces of the first cuneiform and the first metatarsal to provide proper alignment of the body  1910  with the metatarsocuneiform joint (e.g., the joint between the first metatarsal and the medial cuneiform bone, aka a TMT joint). In another embodiment, the body  1910  is configured to reside or sit between the medial surfaces and the dorsal surfaces, or on the medial surfaces of the first cuneiform and the first metatarsal to provide proper alignment of the body  1910  with the metatarsocuneiform joint (e.g., the joint between the first metatarsal and the medial cuneiform bone) for an osteotomy. 
     In certain embodiments, the bone engagement surface  1924  may include a cuneiform apposition portion  1926  and a metatarsal apposition portion  1928 . As shown, the cuneiform apposition portion  1926  may be contoured to match the contour of the surface of the first cuneiform on which it is to rest, and the metatarsal apposition portion  1928  may similarly be contoured to match the contour of the surface of the first metatarsal on which it is to rest. (See  FIG. 19C ) Thus, the body  1910  may have only one stable position and orientation relative to the first cuneiform and the first metatarsal during a surgical osteotomy for correcting the condition. 
     Advantageously, the fidelity of the patient imaging data enables the bone model, preliminary cutting guide model, and patient specific instrument (e.g., patient specific cutting guide, patient specific pin guide, patient specific alignment guide, etc.) to uniquely match a particular patient. Consequently, the bone engagement surface  1924  can engage the surfaces of the bones of a joint in a single configuration. Such a close matching fit facilitates the surgical osteotomy. 
       FIG. 19D  illustrates the cutting guide  1900  from a view facing the medial side  1916 .  FIG. 19E  illustrates the cutting guide  1900  from a view facing the lateral side  1918 . In certain embodiments, the cutting guide  1900  may include one or more features that facilitate use of the cutting guide  1900  while avoiding certain soft tissue in the vicinity of a joint. For example, the medial side  1916  may include a medial superior surface  1932  and a medial inferior surface  1934  that meet at a medial edge  1936 . Advantageously, the medial inferior surface  1934  may extend from inferior side  1922  to the medial edge  1936  at an angle such that the medial inferior surface  1934  does not impinge soft tissue near the joint (e.g., near a medial end of the joint). In certain embodiments, the angle may range between about 80 and about 170 degrees. In another example, the lateral side  1918  may include a lateral superior surface  1942  and a lateral inferior surface  1944  that meet at a lateral edge  1946 . Of course, the medial superior surface  1932  may extend from the superior side  1920  to the medial edge  1936  at an angle. The angle of the medial superior surface  1932  may enable use of the cutting guide  1900  in tighter openings and thus minimize the size of incisions used for a procedure. 
     Advantageously, the lateral inferior surface  1944  may extend from inferior side  1922  to the lateral edge  1946  at an angle such that the lateral inferior surface  1944  does not impinge soft tissue near the joint (e.g., near a medial end of the joint). In certain embodiments, the angle may range between about 80 and about 170 degrees. Of course, the lateral superior surface  1942  may extend from the superior side  1920  to the lateral edge  1946  at an angle. The angle of the lateral superior surface  1942  may enable use of the cutting guide  1900  in tighter openings and thus minimize the size of incisions used for a procedure. 
     The body  1910  may further include guide features that guide a cutter to resect the first cuneiform and the first metatarsal in the manner needed to make the desired correction. For example, the guide features may be used to guide a planar cutting blade, an arcuate cutting blade, a drill or mill, a burr, and/or the like. 
     In the embodiment of  FIGS. 19A through 19H , the guide features may guide a reciprocating planar blade, such as that of a surgical bone saw, that forms planar cuts in the first cuneiform and the first metatarsal. Various manual or powered tools may be used to form the planar cuts. In one embodiment, a sagittal bone saw can be used. In one example, the guide features may take the form of a first slot  1960  and a second slot  1970 . The first slot  1960  may include a lateral end  1962  and a medial end  1964 . The second slot  1970  may include a lateral end  1972  and a medial end  1974 . 
     In one embodiment, the first slot  1960  and the second slot  1970  extend from the superior side  1920  to the inferior side  1922 . In certain embodiments, the first slot  1960  may extend from near the lateral side  1918  to near the medial side  1916 . In other embodiments, one of, or both of, the first slot  1960  and the second slot  1970  may extend from one of the medial side  1916  or the lateral side  1918  of the body  1910 . In certain embodiments, the first slot  1960  and second slot  1970  intersect. In other embodiments, the first slot  1960  and second slot  1970  do not intersect. 
     Thus, upon desired positioning of the cutting guide  1900 , the second slot  1970  may be positioned over at least a portion of the first cuneiform to facilitate resection of the first cuneiform, while the first slot  1960  may be positioned over at least a portion of the first metatarsal to facilitate resection of the first metatarsal. In one embodiment, the second slot  1970  is positioned near the distal end of the first cuneiform and the first slot  1960  is positioned near the proximal end of the first metatarsal. The first slot  1960  and second slot  1970  together, with the bone engagement surface  1924  overlying the first cuneiform and the first metatarsal, are positioned to guide resection of the first cuneiform and the first metatarsal during a surgical osteotomy for correcting a condition. 
     In alternative embodiments, a guide feature may be designed to guide a different type of cutter, such as a drill, mill, or side-cutting burr. In such embodiments, the guide feature may not be a slot, but may instead be a translatable or rotatable cutter retainer that guides translation and/or rotation of the cutter relative to the bone. In certain embodiments, two or more guide features may be replaced by a single guide feature sized to permit a surgeon to resect both a first cuneiform and a first metatarsal using a single cutting guide  1900 . 
     In one embodiment, a first guide feature is configured to define a first cut surface that can be formed by resecting a first bone. A second guide feature is configured to define a second cut surface that can be formed by resecting a second bone. In such an embodiment, one or the other or both of the first cut surface and the second cut surface can be oriented according to one or more angles relative to landmarks on the bones or other anatomical structures. 
     Alternatively, or in addition, in certain embodiments, one or both of, the first guide feature and second guide feature may be positioned on, or in, the body  1910  and/or have an orientation based on patient imaging data. The patient imaging data can be used to position and orient one, or both, of the first guide feature and second guide feature such that formation of one, or both, of the first cut surface and the second cut surface and fixation of the two cut surfaces against each other mitigates a condition of the patient. For example, as described in the present disclosure, patient imaging data can be used to generate bone models of bones of the patient. The bone models can be used to determine and/or define contours for a bone engagement surface  1924 , a position for a first slot  1960 , an orientation for a first slot  1960 , a position for a second slot  1970 , an orientation for a second slot  1970 , as well as other features and attributes of one or more patient specific instruments that can be used in a procedure. 
     “Cut surface” refers to a surface of an object that is created or formed by the removal of one or more parts of the object that includes the original surface. Cut surfaces can be created using a variety of methods, tools, or apparatuses and may be formed using a variety of removal actions, including, but not limited to, fenestrating, drilling, abrading, cutting, sawing, chiseling, digging, scrapping, and the like. Tools and/or methods used for forming a cut surface can include manual, mechanical, motorized, hydraulic, automated, robotic, and the like. In certain embodiments, the cut surface(s) are planar. 
     “Orientation” refers to a direction, angle, position, condition, state, or configuration of a first object, component, part, apparatus, system, or assembly relative to another object, component, part, apparatus, system, assembly, reference point, reference axis, or reference plane. 
       FIG. 20  illustrates one embodiment of the cutting guide  1900  secured to a first metatarsal  230  and a first cuneiform  210 . In the illustrated embodiment, the first guide feature may take the form of the first slot  1960  and the second guide feature may take the form of the second slot  1970 . Referring now to  FIGS. 20 and 19D , the position and/or angles (e.g., orientation) of one or both of the guide features based on patient imaging data is illustrated. In the illustrated embodiment, the first slot  1960  is positioned between the distal side  1914  and the second slot  1970 . The first slot  1960  is oriented based on a desired angle for mitigating the condition of the patient. In one example, the first slot  1960  is angled perpendicular to a longitudinal axis of the first metatarsal  230 . This orientation of the first slot  1960  enables the first cut surface to extend from the body  1910  toward the bone to form a cut surface that is also perpendicular to the longitudinal axis  1976  of one of the bones of a joint. “Longitudinal axis” refers to an axis of a structure, device, object, apparatus, or part thereof that extends from one end of a longest dimension to an opposite end. Typically, a longitudinal axis passes through a center of the structure, device, object, apparatus, or part thereof along the longitudinal axis. The center point used for the longitudinal axis may be a geometric center point and/or a mass center point. In the illustrated embodiment, the longitudinal axis  1976  is the longitudinal axis of the first metatarsal  230 . 
     In the illustrated embodiment, the second slot  1970  is positioned between the proximal side  1912  and the first slot  1960 . In addition in the illustrated embodiment, the second slot  1970  is oriented based on a desired angle for mitigating the condition of the patient. In the illustrated embodiment, the orientation of the second slot  1970  can be described in reference to a first angle A and a second angle B.  FIG. 19D  illustrates first angle A. In one embodiment, a second cut surface formed by resection using second slot  1970  extends inferiorly away from a first cut surface formed by resection using first slot  1960 . Described another way, angle A is an angle between a first plane  1978  that includes the first slot  1960  and a first cut surface formed by resection using first slot  1960  and a second plane that includes the second slot  1970  and a second cut surface formed by resection using second slot  1970 , the second plane extending from the first plane toward the proximal side  1912  of the body  1910 . In certain embodiments, angle A can range between about 4 degrees to about 18 degrees. In certain embodiments, angle A may start at 0 degrees and then increase to a positive number of degrees as illustrated or decrease to a negative number of degrees depending on how a surgeon may prescribe adjustments for a correction. 
       FIG. 19H  illustrates second angle B. In one embodiment, a second cut surface formed by resection using second slot  1970  extends posteriorly away from a first cut surface formed by resection using first slot  1960 . Described another way, in the illustrated embodiment, angle B is an angle between the first plane  1978  that includes the first slot  1960  and a first cut surface formed by resection using first slot  1960  and a third plane  1981  that includes the second slot  1970  and a second cut surface formed by resection using second slot  1970 , the third plane  1981  extending from the first plane toward the proximal side  1912  of the body  1910 . In certain embodiments, angle B can range between about 0 degrees to about 35 degrees. In certain embodiments, angle B may start at 0 degrees and then increase to a positive number of degrees as illustrated or decrease to a negative number of degrees depending on how a surgeon may prescribe adjustments for a correction. 
     Those of skill in the art will appreciate that the position and orientation of the first slot  1960  and second slot  1970  and the corresponding cut surface a surgeon can form using these guide features can vary depending on the anatomical structures of the patient, the osteotomy procedure being performed, preferences of the surgeon, the nature of the condition, and the like. For example in the illustrated embodiment, the medial end  1964  of the first slot  1960  is closer to the medial end  1974  of the second slot  1970  than the lateral end  1962  is in relation to the lateral end  1972 . In another embodiment, the lateral end  1962  of the first slot  1960  may be closer to the lateral end  1972  of the second slot  1970  than the medial end  1964  is in relation to the medial end  1974 . Of course in another embodiment, the first slot  1960  and second slot  1970  may be configured such that a first distance between lateral end  1962  and lateral end  1972  and a second distance between medial end  1964  and medial end  1974  are substantially the same. 
     Referring to  FIG. 19D , in one embodiment, anatomical data about the patient can be used to define other structures of the cutting guide  1900  or other patient specific instruments. For example, anatomical data about the patient that can be captured in the patient imaging data (e.g., due to the fidelity of the technology providing the patient imaging data) can be used to define how deep a first guide feature and/or second guide feature is. Controlling the depth of the first guide feature and/or second guide feature can be used to manage how deep a surgeon&#39;s cutting instruments can reach within the first guide feature and/or second guide feature. Managing a depth for one or more guide features may be referred to as defining a patient specific height for the cutting guide  1900 . 
     For example, in one embodiment, patient imaging data can be used to define a distance between at a first top edge  1966  of the first guide feature (e.g., first slot  1960 ) and the first surface (e.g., a surface of a first bone such as a first metatarsal  230 ). Alternatively, or in addition, patient imaging data can be used to define a distance between at a second top edge  1968  of the second guide feature (e.g., second slot  1970 ) and the second surface (e.g., a surface of a second bone such as a first cuneiform  210 ). Managing the distance between a first top edge  1966  and/or second top edge  1968  and a bone surface is one way to provide a stop within the cutting guide  1900 . The stop can serve to limit how deep a surgeon will resect hard tissue/soft tissue when using the cutting guide  1900  for a procedure. If a surgeon resects until the resection instruments engages the stop, the surgeon can be assured that the resection extends to a desired depth (not too far and not too short). 
     As used herein, a “stop” refers to an apparatus, instrument, structure, member, device, component, system, or assembly structured, organized, configured, designed, arranged, or engineered to prevent, limit, impede, stop, or restrict motion or movement and/or operation of the another object, member, structure, component, part, apparatus, system, or assembly. 
     Referring to  FIGS. 19H and 20 , in one embodiment, the body  1910 , or one or more arms, may include one or more bone attachment features that facilitate attachment of the body  1910  to the first cuneiform  210  and/or first metatarsal  230 . Such bone attachment features may include any of a wide variety of fasteners including, but not limited to, holes, spikes, fastening devices, and/or the like. 
     As used herein, a “fastener”, “fixation device”, or “fastener system” refers to any structure configured, designed, or engineered to join two structures. Fasteners may be made of a variety of materials including metal, plastic, composite materials, metal alloys, plastic composites, and the like. Examples of fasteners include, but are not limited to screws, rivets, bolts, nails, snaps, hook and loop, set screws, bone screws, nuts, posts, pins, thumb screws, and the like. Other examples of fasteners include, but are not limited to wires, Kirschner wires (K-wire), anchors, bone anchors, plates, bone plates, intramedullary nails or rods or pins, implants, sutures, soft sutures, soft anchors, tethers, interbody cages, fusion cages, and the like. In certain embodiments, the term fastener may refer to a fastener system that includes two or more structures configured to combine to serve as a fastener. An example of a fastener system is a rod or shaft having external threads and an opening or bore within another structure having corresponding internal threads configured to engage the external threads of the rod or shaft. In certain embodiments, the term fastener may be used with an adjective that identifies an object or structure that the fastener may be particularly configured, designed, or engineered to engage, connect to, join, contact, or couple together with one or more other structures of the same or different types. For example, a “bone fastener” may refer to an apparatus for joining or connecting one or more bones, one or more bone portions, soft tissue and a bone or bone portion, hard tissue and a bone or bone portion, an apparatus and a bone or portion of bone, or the like. 
     Effective connection of the cutting guide  1900  to one or more bones across a joint can ensure that cut surfaces are formed in desired locations and orientation and mitigate removal of hard tissue and/or soft tissue outside in undesired locations. 
     Accordingly, the cutting guide  1900  includes one or more bone attachment features. As embodied in  FIGS. 19A through 19H , the bone attachment features may take the form of one or more holes  1950  that extend from the inferior side  1922  to the superior side  1920  and/or one or more fixation devices. The holes  1950  may be shaped to accommodate pins, K-wires, and/or other elongated bone fixation elements that can be anchored in the first cuneiform  210  and/or the first metatarsal  230  to keep the cutting guide  1900  in place. 
       FIG. 20  illustrates one example of a cutting guide  1900  coupled to the bones using a proximal bone attachment feature  1952  and a distal bone attachment feature  1954 . In the illustrated embodiment, the proximal bone attachment feature  1952  includes at least one hole  1950  and a fastener and the distal bone attachment feature  1954  includes at least one hole  1950  and a fastener. In  FIG. 20  the fasteners are K-wires. Advantageously, the proximal bone attachment feature  1952  and the distal bone attachment feature  1954  each include at least two holes  1950 , each with a K-wire passing through the hole  1950  and into bone facing the inferior side  1922 . Using two holes  1950  and two fasteners ensures a stable coupling between the cutting guide  1900  and the bone(s). Advantageously, in certain embodiments, the two holes  1950  of the proximal bone attachment feature  1952  and distal bone attachment feature  1954  are align such that inserted K-wires are parallel to each other. Among other benefits, parallel K-wires of each of the proximal bone attachment feature  1952  and distal bone attachment feature  1954  prevent the cutting guide  1900  from pivoting around one of the K-wires of a proximal bone attachment feature  1952  or a distal bone attachment feature  1954 . 
     In the illustrated embodiment, the proximal arm  1930  includes the proximal bone attachment feature  1952  and the distal arm  1940  includes the distal bone attachment feature  1954 . In one embodiment, the holes  1950  of the proximal bone attachment feature  1952  are aligned with each other and aligned perpendicular to a guide feature such as the second slot  1970 . The holes  1950  of the distal bone attachment feature  1954  may also be aligned with each other and aligned perpendicular to another guide feature such as the first slot  1960 . This means that the aligned holes  1950  (and K-wires secured within them) of the distal bone attachment feature  1954  will also be perpendicular to the cut surface formed using the first slot  1960 . This also means that the aligned holes  1950  (and K-wires secured within them) of the proximal bone attachment feature  1952  will also be perpendicular to the cut surface formed using the second slot  1970 . Consequently, at least one of the proximal bone attachment feature  1952  and the distal bone attachment feature  1954  can be used to position and orient a cut surface of the first metatarsal  230  and a cut surface of the first cuneiform  210 . 
     Returning to  FIGS. 19A through 20 , the body  1910  may further have features that facilitate desired translation and orientation of the first metatarsal  230  and/or first cuneiform  210  in order to fuse or join the two bones to complete the procedure. For example, in the illustrated embodiment, the cutting guide  1900  may include at least one alignment feature. A second alignment feature may be integrated into the cutting guide  1900  or the second alignment feature may be a separate feature from the cutting guide  1900 . 
     In the illustrated embodiment, the proximal bone attachment feature  1952  serves as both a bone attachment feature and as an alignment feature, e.g., proximal alignment feature  1980 . In this manner, the proximal bone attachment feature  1952  can provide both a bone attachment feature and an alignment feature in a single feature. In situations where a second bone of a joint, such as a first metatarsal  230 , does not need to be rotated, translated, and/or reoriented to mitigate a patient&#39;s condition, the distal bone attachment feature  1954  may also serve as both a bone attachment feature and as an alignment feature, e.g., distal alignment feature  1990 . 
     Typically, in an osteotomy for a condition such as a hallux valgus, it is desirable to rotate the first metatarsal  230  to address the condition. The first metatarsal  230  may be rotated for example to re-position distal plantar sesamoids from a lateral orientation to a more plantar orientation. Research has shown that performing such re-orientation mitigates recurrence of a hallux valgus condition. In such situations, the distal bone attachment feature  1954  may serve as a bone attachment feature and as a reference for the positioning of a distal alignment feature  1990  that is separate from the cutting guide  1900 . 
     For example, in such instances, the distal bone attachment feature  1954  may serve as a reference for placement of a distal alignment feature  1990  (See  FIG. 24A ) that is parallel to the distal bone attachment feature  1954  as measured along the longitudinal axis  1976  of the first metatarsal  230 . Subsequent to formation of a cut surface on the first metatarsal  230 , the distal alignment feature  1990  can be coupled to the first metatarsal  230  in parallel to the distal bone attachment feature  1954  (e.g., by way of a pin guide). In certain embodiments, the distal alignment feature  1990  can include two or more aligned holes and/or a pair of K-wires that enter the bone in parallel to each other. In addition, in such a situation, the proximal alignment feature  1980  and the distal alignment feature  1990  may not be aligned initially. Instead, the proximal alignment feature  1980  and distal alignment feature  1990  may be configured to align when the bone coupled to the distal alignment feature  1990  is rotated. Fasteners  1956  of the distal bone attachment feature  1954  may be aligned with longitudinal axis  1976  and perpendicular to first slot  1960  by way of holes  1950 . Fasteners  1956  of the proximal bone attachment feature  1952  may be aligned with reference line  1992  and perpendicular to second slot  1970  by way of holes  1950 . The reference line  1992  may not be aligned with the longitudinal axis  1976 . 
       FIG. 20  illustrates an example cutting guide  1900  seated transverse to a tarsometatarsal (“TMT”) joint  2000 . The TMT joint  2000  includes a lateral end  2002  and a medial end  2004 . In certain embodiments, such as the illustrated embodiment, the body  1910  is configured to extend between the lateral end  2002  and the medial end  2004 . In addition, the proximal arm  1930  and the distal arm  1940  may be aligned with each other. 
     Furthermore, in certain embodiments, the proximal arm  1930  and the distal arm  1940  may be positioned extending from the body  1910  near the lateral end  2002  (See  FIG. 23 ). Said another way, the proximal arm  1930  and the distal arm  1940  may be positioned extending from the body  1910  such that the arms extend over a dorsal surface of the first cuneiform  210  and a dorsal surface of the first metatarsal  230 . In another embodiment, the proximal arm  1930  and the distal arm  1940  may be positioned extending from the body  1910  near the medial end  2004 . 
       FIG. 20  illustrates an example cutting guide  1900  at a particular stage in an osteotomy procedure. In one embodiment, a surgeon has formed an incision transverse to a TMT joint  2000  with a dorsal approach. In the illustrated embodiment, the cutting guide  1900  may be configured (e.g., the bone engagement surface  1924 ) to seat between the dorsal surface and medial surface of both the first cuneiform  210  and the first metatarsal  230 . The surgeon has also formed the incision down to the cortical bone surface of the first cuneiform  210  and the first metatarsal  230 . Further, the surgeon has cut, or moved to the side, soft tissue covering the cortical bone surface of the first cuneiform  210  and the first metatarsal  230  sufficient to seat the bone engagement surface  1924  onto the cortical bone surface of the first cuneiform  210  and the first metatarsal  230 . 
     A surgeon has deployed two or more fasteners  1956  (e.g., K-wires) through the holes  1950  of the proximal bone attachment feature  1952  and the distal bone attachment feature  1954 . In certain embodiments, the distal bone attachment feature  1954  and/or the proximal bone attachment feature  1952  can include an additional hole  1958  for another fastener  1956 . The additional hole  1958  and fastener  1956  can help keep the cutting guide  1900  in place during resection and alignment operations. In certain embodiments, the additional hole  1958  is aligned with another two holes  1950  of the distal arm  1940  but need not be aligned. 
     Next, a surgeon can resect a distal articular surface of the first cuneiform  210  and a proximal articular surface of the first metatarsal  230  by way of the second slot  1970  and the first slot  1960 . After resection, the distal end of the first cuneiform  210  includes a planar cut surface and the proximal end of the first metatarsal  230  includes a planar cut surface.  FIG. 20  illustrates that the bone engagement surface  1924  conforms to the surface of the two bones (e.g., first cuneiform  210  and first metatarsal  230 ). 
       FIGS. 21A, 21B  illustrate a perspective view of a first cuneiform and a first metatarsal with one embodiment of a patient-specific cutting guide. Prior to resection completed in the illustrated stage of  FIG. 20 , a surgeon may desire to check or confirm that the desired cutting guide is being used and that a selected cutting guide will provide a desired alignment between the bones of the foot after the resection and fixation steps. 
     Accordingly, in the illustrated embodiment, the cutting guide  1900  may include one member of a coupler  2010  configured to engage a corresponding member of the coupler coupled to an alignment guide  2020 . Those of skill in the art appreciate that various designs of a coupler may be used. In the illustrated embodiment, the coupler  2010  includes an opening  2012  (See  FIG. 20 ) that may extend from the superior side  1920  into the body  1910  through to the inferior side  1922  and a post  2014 . In one embodiment, the opening  2012  may include one of the slots, such as second slot  1970 . The post  2014  may include an engagement member  2016 . 
     In one embodiment, the opening  2012  and the post  2014  engage each other in a friction fit. For example, the post  2014  may slide into the second slot  1970  and the engagement member  2016  may slide into the opening  2012 . In one embodiment, the engagement member  2016  may include tabs that are biased outward and greater than a diameter of the opening  2012  such that the tabs engage the opening  2012  when inserted and release the opening when the tabs are pressed together. 
     The alignment guide  2020  includes a body  2022 , an inferior end  2024 , and superior end  2026  and one or more openings  2028  near the superior end  2026 . The openings  2028  may be aligned. A surgeon may use the alignment guide  2020  by engaging the coupler  2010  to couple the alignment guide  2020  to the cutting guide  1900 . Next, a surgeon may insert one or more K-wires through the openings. The openings  2028  and alignment guide  2020  may be configured such that K-wires within the openings extend along an anterior-posterior axis and indicate the orientation and alignment of the first cuneiform  210  and first metatarsal  230  once the osteotomy procedure is completed. A surgeon may compare this alignment with the orientation and alignment of other bones of the patient. In this manner, a surgeon can confirm that osteotomy procedure will accomplish the desired outcome once completed. 
       FIGS. 22A-22H  are top perspective, top, bottom, front elevation, rear elevation, right, left, and alternative top perspective, respectively, of a patient-specific cutting guide  2200  according to one embodiment. The cutting guide  2200  may be designed to facilitate resection of a first cuneiform near a distal end and a first metatarsal near a proximal end with planar cuts at the proper angles to provide dual-plane correction of the orientation of the first metatarsal relative to the first cuneiform, thereby providing correction in a lateral direction, in a plantar direction, and/or a dorsal direction. 
     As shown, the cutting guide  2200  may have a body  2210  with a monolithic construction and the general shape of a rectangular shape. The body  2210  includes a proximal side  2212 , a distal side  2214 , a medial side  2216 , a lateral side  2218 , a superior side  2220 , and an inferior side  2222 . In the illustrated embodiment, the body  2210  may also include a proximal arm  2230  that extends from the body  2210  and a distal arm  2240  that extends from the body  2210 . The proximal side  2212  is the side closest to the core of the patient when the cutting guide  2200  is in use. The distal side  2214  is the side furthest from the core of the patient when the cutting guide  2200  is in use. The medial side  2216  is the side facing medially when the cutting guide  2200  is in use. The lateral side  2218  is the side facing laterally when the cutting guide  2200  is in use. The superior side  2220  is the side facing up away from the bone(s) when the cutting guide  2200  is in use. The inferior side  2222  is the side facing down, facing, and/or contacting the bone(s) (e.g., contacting a surface of one or more bones) when the cutting guide  2200  is in use. 
     The inferior side  2222  may be custom contoured to match the shapes of one or more of the surfaces of the first cuneiform and/or the first metatarsal. In one embodiment, the inferior side  2222  may include a bone engagement surface  2224 . The bone engagement surface  2224  can be shaped to match a first surface of a first bone and a second surface of a second bone of a joint. 
     In one example, the bone engagement surface  2224  can be shaped such that the bone engagement surface  2224  matches a surface of a cuneiform bone and a surface of a metatarsal bone of a tarsometatarsal (“TMT”) joint. The bone engagement surface  2224  can be so shaped because it is fabricated from a bone model of the patient&#39;s bones. The body  2210  is configured, designed, and/or fabricated to seat transverse to a joint (e.g., a TMT joint) with the bone engagement surface  2224  engaging a first surface of a first bone and a second surface of a second bone. 
       FIGS. 22A-22H  includes similar components, parts, devices, apparatus, features, and aspects as those disclosed and described in relation to  FIGS. 19A-19H , however the difference in  FIGS. 22A-22H  is that body  2210 , bone engagement surface  2224 , and/or one or more arms (e.g., proximal arm  2230  and/or distal arm  2240 ) are configured to couple to the bones and extend transverse to the joint, at least partially, if not completely, on the dorsal sides of the bones. Accordingly, the cutting guide  2200  may be referred to as a dorsal cutting guide. 
     In addition, the cutting guide  2200  may be configured to avoid contact with soft tissue such as nerves, tendons, blood vessels, and the like that may run along a medial and/or a lateral side of the first metatarsal  230 . Accordingly, the cutting guide  2200  may be fabricated to seat transverse to the TMT joint such that the bone engagement surface contacts a dorsal surface of the a first bone (e.g., first cuneiform  210 ) and/or a second bone (e.g., first metatarsal  230 ). For example, the proximal arm  2230  and/or distal arm  2240  may be positioned more laterally than in other embodiments. 
     In the illustrated embodiment, the body  2210  is configured to reside on the dorsal surfaces of the first cuneiform and the first metatarsal to provide proper alignment of the body  2210  with the metatarsocuneiform joint (e.g., the joint between the first metatarsal and the medial cuneiform bone, aka a TMT joint). In another embodiment, the body  2210  is configured to reside or sit between the medial surfaces and the dorsal surfaces for an osteotomy. 
     In certain embodiments, the bone engagement surface  2224  may include a cuneiform apposition portion  2226  and a metatarsal apposition portion  2228 . As shown, the cuneiform apposition portion  2226  may be contoured to match the contour of the surface of the first cuneiform on which it is to rest, and the metatarsal apposition portion  2228  may similarly be contoured to match the contour of the surface of the first metatarsal on which it is to rest. (See  FIG. 22C ) Thus, the body  2210  may have only one stable position and orientation relative to the first cuneiform and the first metatarsal during a surgical osteotomy for correcting the condition. 
     Advantageously, the fidelity of the patient imaging data enables the bone model, preliminary cutting guide model, and patient specific instrument (e.g., patient specific cutting guide, patient specific pin guide, patient specific alignment guide, etc.) to uniquely match a particular patient. Consequently, the bone engagement surface  2224  can engage the surfaces of the bones of a joint in a single configuration. Such a close matching fit facilitates the surgical osteotomy. 
       FIG. 22D  illustrates the cutting guide  2200  from a view facing the medial side  2216 .  FIG. 22E  illustrates the cutting guide  2200  from a view facing the lateral side  2218 . In certain embodiments, the cutting guide  2200  may include one or more features that facilitate use of the cutting guide  2200  while avoiding certain soft tissue in the vicinity of a joint. For example, the medial side  2216  may include a medial superior surface  2232  and a medial inferior surface  2234  that meet at a medial edge  2236 . Advantageously, the medial inferior surface  2234  may extend from inferior side  2222  to the medial edge  2236  at an angle such that the medial inferior surface  2234  does not impinge soft tissue near the joint (e.g., near a medial end of the joint). In certain embodiments, the angle may range between about 80 and 170 degrees. In another example, the lateral side  2218  may include a lateral superior surface  2242  and a lateral inferior surface  2244  that meet at a lateral edge  2246  (See  FIG. 22E ). Of course, the medial superior surface  2232  may extend from the superior side  2220  to the medial edge  2236  at an angle. The angle of the medial superior surface  2232  may enable use of the cutting guide  2200  in tighter openings and thus minimize the size of incisions used for a procedure. 
     Advantageously, the lateral inferior surface  2244  may extend from inferior side  2222  to the lateral edge  2246  at an angle such that the lateral inferior surface  2244  does not impinge soft tissue near the joint (e.g., near a medial end of the joint). In certain embodiments, the angle may range between about 80 and 170 degrees. Of course, the lateral superior surface  2242  may extend from the superior side  2220  to the lateral edge  2246  at an angle. The angle of the lateral superior surface  2242  may enable use of the cutting guide  2200  in tighter openings and thus minimize the size of incisions used for a procedure. 
     The body  2210  may further include guide features that guide a cutter to resect the first cuneiform and the first metatarsal in the manner needed to make the desired correction. For example, the guide features may be used to guide a planar cutting blade, an arcuate cutting blade, a drill or mill, a burr, and/or the like. 
     In the embodiment of  FIGS. 22A through 22H , the guide features may guide a reciprocating planar blade, such as that of a surgical bone saw, that forms planar cuts in the first cuneiform and the first metatarsal. Various manual or powered tools may be used to form the planar cuts. In one embodiment, a sagittal bone saw can be used. In one example, the guide features may take the form of a first slot  2260  and a second slot  2270 . The first slot  2260  may include a lateral end  2262  and a medial end  2264 . The second slot  2270  may include a lateral end  2272  and a medial end  2274 . 
     In one embodiment, the first slot  2260  and the second slot  2270  extend from the superior side  2220  to the inferior side  2222 . In certain embodiments, the first slot  2260  may extend from near the lateral side  2218  to near the medial side  2216 . In other embodiments, one of, or both of, the first slot  2260  and the second slot  2270  may extend from one of the medial side  2216  or the lateral side  2218  of the body  2210 . In certain embodiments, the first slot  2260  and second slot  2270  intersect. In other embodiments, the first slot  2260  and second slot  2270  do not intersect. 
     Thus, upon desired positioning of the cutting guide  2200 , the second slot  2270  may be positioned over at least a portion of the first cuneiform to facilitate resection of the first cuneiform, while the first slot  2260  may be positioned over at least a portion of the first metatarsal to facilitate resection of the first metatarsal. In one embodiment, the second slot  2270  is positioned near the distal end of the first cuneiform and the first slot  2260  is positioned near the proximal end of the first metatarsal. The first slot  2260  and second slot  2270  together, with the bone engagement surface  2224  overlying the first cuneiform and the first metatarsal, are positioned to guide resection of the first cuneiform and the first metatarsal during a surgical osteotomy for correcting a condition. 
     In alternative embodiments, a guide feature may be designed to guide a different type of cutter, such as a drill, mill, or side-cutting burr. In such embodiments, the guide feature may not be a slot, but may instead be a translatable or rotatable cutter retainer that guides translation and/or rotation of the cutter relative to the bone. In certain embodiments, two or more guide features may be replaced by a single guide feature sized to permit a surgeon to resect both a first cuneiform and a first metatarsal using a single cutting guide  2200 . 
     In one embodiment, a first guide feature is configured to define a first cut surface that can be formed by resecting a first bone. A second guide feature is configured to define a second cut surface that can be formed by resecting a second bone. In such an embodiment, one or the other or both of the first cut surface and the second cut surface can be oriented according to one or more angles relative to landmarks on the bones or other anatomical structures. 
     Alternatively, or in addition, in certain embodiments, one or both of, the first guide feature and second guide feature may be positioned on, or in, the body  2210  and/or have an orientation based on patient imaging data. The patient imaging data can be used to position and orient one, or both, of the first guide feature and second guide feature such that formation of one, or both, of the first cut surface and the second cut surface and fixation of the two cut surfaces against each other mitigates a condition of the patient. For example, as described in the present disclosure, patient imaging data can be used to generate bone models of bones of the patient. The bone models can be used to determine and/or define contours for a bone engagement surface  2224 , a position for a first slot  2260 , an orientation for a first slot  2260 , a position for a second slot  2270 , an orientation for a second slot  2270 , as well as other features and attributes of one or more patient specific instruments that can be used in a procedure. 
       FIG. 23  illustrates a perspective view of a first cuneiform and a first metatarsal with one embodiment of a patient-specific cutting guide positioned over a TMT joint. In the illustrated embodiment, the first guide feature may take the form of the first slot  2260  and the second guide feature may take the form of the second slot  2270 . As with the embodiment of  FIGS. 19A-19H and 20 , the position and/or angles (e.g., orientation) of one or both of the guide features based on patient imaging data is illustrated. The first slot  2260  is oriented based on a desired angle for mitigating the condition of the patient. In one example, the first slot  2260  is angled perpendicular to a longitudinal axis  2276  of the first metatarsal  230 . This orientation of the first slot  2260  enables the first cut surface to extend from the body  2210  toward the bone to form a cut surface that is also perpendicular to the longitudinal axis  2276  of one of the bones of a joint. 
     In the illustrated embodiment, the second slot  2270  is positioned and oriented based on a desired angle for mitigating the condition of the patient. In the illustrated embodiment, the orientation of the second slot  2270  can be described in reference to a first angle A and a second angle B, just as those angles are described above in relation to  FIGS. 19D and 19H . 
     Those of skill in the art will appreciate that the position and orientation of the first slot  2260  and second slot  2270  and the corresponding cut surface a surgeon can form using these guide features can vary depending on the anatomical structures of the patient, the osteotomy procedure being performed, preferences of the surgeon, the nature of the condition, and the like. 
     Referring to  FIGS. 22H and 23 , in one embodiment, the body  2210 , or one or more arms, may include one or more bone attachment features that facilitate attachment of the body  2210  to the first cuneiform  210  and/or first metatarsal  230 . Such bone attachment features may include any of a wide variety of fasteners including, but not limited to, holes, spikes, fastening devices, and/or the like. Effective connection of the cutting guide  2200  to one or more bones across a joint can ensure that cut surfaces are formed in desired locations and orientation and mitigate removal of hard tissue and/or soft tissue outside in undesired locations. 
     Accordingly, the cutting guide  2200  includes one or more bone attachment features. As embodied in  FIGS. 22A through 22H , the bone attachment features may take the form of one or more holes  2250  that extend from the inferior side  2222  to the superior side  2220  and/or one or more fixation devices. The holes  2250  may be shaped to accommodate pins, K-wires, and/or other elongated bone fixation elements that can be anchored in the first cuneiform  210  and/or the first metatarsal  230  to keep the cutting guide  2200  in place. 
       FIG. 23  illustrates one example of a cutting guide  2200  coupled to the bones using a proximal bone attachment feature  2252  and a distal bone attachment feature  2254 . In the illustrated embodiment, the proximal bone attachment feature  2252  includes at least one hole  2250  and a fastener and the distal bone attachment feature  2254  includes at least one hole  2250  and a fastener. In  FIG. 23  the fasteners are K-wires. Advantageously, the proximal bone attachment feature  2252  and the distal bone attachment feature  2254  each include at least two holes  2250 , each with a K-wire passing through the hole  2250  and into bone facing the inferior side  2222 . Using two holes  2250  and two fasteners ensures a stable coupling between the cutting guide  2200  and the bone(s). Advantageously, in certain embodiments, the two holes  2250  of the proximal bone attachment feature  2252  and distal bone attachment feature  2254  are align such that inserted K-wires are parallel to each other. Among other benefits, parallel K-wires of each of the proximal bone attachment feature  2252  and distal bone attachment feature  2254  prevent the cutting guide  2200  from pivoting around one of the K-wires of a proximal bone attachment feature  2252  or a distal bone attachment feature  2254 . 
     In the illustrated embodiment, the proximal arm  2230  includes the proximal bone attachment feature  2252  and the distal arm  2240  includes the distal bone attachment feature  2254 . In one embodiment, the holes  2250  of the proximal bone attachment feature  2252  are aligned with each other and aligned perpendicular to a guide feature such as the second slot  2270  (see reference line  1992 ). The holes  2250  of the distal bone attachment feature  2254  may also be aligned with each other and aligned perpendicular to another guide feature such as the first slot  2260  (see reference line  1994 ). This means that the aligned holes  2250  (and K-wires secured within them) of the distal bone attachment feature  2254  will also be perpendicular to the cut surface formed using the first slot  2260 . This also means that the aligned holes  2250  (and K-wires secured within them) of the proximal bone attachment feature  2252  will also be perpendicular to the cut surface formed using the second slot  2270 . Consequently, at least one of the proximal bone attachment feature  2252  and the distal bone attachment feature  2254  can be used to position and orient a cut surface of the first metatarsal  230  and a cut surface of the first cuneiform  210 . In certain embodiments, the proximal bone attachment feature  2252  and distal bone attachment feature  2254  may not be aligned with each other, the offset in the alignment may be the change in orientation of the bones of the joint desired to address the condition. It should be noted that the distal bone attachment feature  2254  may be parallel to the longitudinal axis  2276 . In this manner, the distal bone attachment feature  2254  can be used as a reference for positioning a distal alignment feature  2290  on the first metatarsal  230 . 
     Returning to  FIGS. 22A through 20 , the body  2210  may further have features that facilitate desired translation and orientation of the first metatarsal  230  and/or first cuneiform  210  in order to fuse or join the two bones to complete the procedure. For example, in the illustrated embodiment, the cutting guide  2200  may include at least one alignment feature. A second alignment feature may be integrated into the cutting guide  2200  or the second alignment feature may be a separate feature from the cutting guide  2200 . 
     In the illustrated embodiment, the proximal bone attachment feature  2252  serves as both a bone attachment feature and as an alignment feature, e.g., proximal alignment feature  2280 . In this manner, the proximal bone attachment feature  2252  can provide both a bone attachment feature and an alignment feature in a single feature. In situations where a second bone of a joint, such as a first metatarsal  230 , does not need to be rotated, translated, and/or reoriented to mitigate a patient&#39;s condition, the distal bone attachment feature  2254  may also serve as both a bone attachment feature and as an alignment feature, e.g., distal alignment feature  2290 . 
     Typically, in an osteotomy for a condition such as a hallux valgus, it is desirable to rotate the first metatarsal  230  to address the condition. The first metatarsal  230  may be rotated for example to re-position distal plantar sesamoids from a lateral orientation to a more plantar orientation. Research has shown that performing such re-orientation mitigates recurrence of a hallux valgus condition. In such situations, the distal bone attachment feature  2254  may serve as a bone attachment feature and as a reference for the positioning of a distal alignment feature  2290  that is separate from the cutting guide  2200 . 
     For example, in such instances, the distal bone attachment feature  2254  may serve as a reference for placement of a distal alignment feature  2290  (See  FIG. 24A ) that is parallel to the distal bone attachment feature  2254  as measured along the longitudinal axis  2276  of the first metatarsal  230 . Subsequent to formation of a cut surface on the first metatarsal  230 , the distal alignment feature  2290  can be coupled to the first metatarsal  230  in parallel to the distal bone attachment feature  2254  (e.g., by way of a pin guide). In certain embodiments, the distal alignment feature  2290  can include two or more aligned holes and/or a pair of K-wires that enter the bone in parallel to each other. In addition, in such a situation, the proximal alignment feature  2280  and the distal alignment feature  2290  may not be aligned initially. Instead, the proximal alignment feature  2280  and distal alignment feature  2290  may be configured to align when the bone coupled to the distal alignment feature  2290  is rotated. 
       FIG. 23  illustrates an example cutting guide  2200  seated transverse to a tarsometatarsal (“TMT”) joint  2000 . The TMT joint  2000  includes a lateral end  2002  and a medial end  2004 . In certain embodiments, such as the illustrated embodiment, the body  2210  is configured to extend between the lateral end  2002  and the medial end  2004 . In this manner, the first slot  2260  and second slot  2270  extend along the TMT joint  2000  in a lateral medial direction and are long enough that a surgeon can readily resect the respective ends of the respective bones of the joint. In addition, the proximal arm  2230  and the distal arm  2240  may be aligned with each other. In one embodiment, the proximal arm  2230  and distal arm  2240  may extend proximal to the lateral side  2218  and/or proximal to the lateral end  2002  of the joint (e.g., TMT joint  2000 ). 
     Advantageously, the cutting guide  2200  can be used with patients that have smaller bones and joints such as children or female patients. The cutting guide  2200  fits directly on the dorsal surfaces of the bones of the joint. This placement can avoid contact with soft tissues that may run along the medial and/or lateral surfaces of the bones of the joint. 
       FIG. 23  illustrates that the cutting guide  2200  can be secured to the bones using the proximal bone attachment feature  2252  and/or distal bone attachment feature  2254  each of which may include two or more fasteners  1956 . In certain embodiments, the fasteners  1956  of the proximal bone attachment feature  2252  are aligned with each other and perpendicular to the second slot  2270 . The fasteners  1956  of the distal bone attachment feature  2254  are aligned with each other and perpendicular to the first slot  2260 . The fit of the bone engagement surface  2224  to the surfaces (dorsal in this embodiment) of the bones helps to secure the cutting guide  2200  in place and ensure that resection of the bones using the first slot  2260  and second slot  2270  forms the desired cut surfaces for the procedure. 
     Those of skill in the art will appreciate that in various embodiments certain aspects may interface with one or more dorsal surfaces of each or both of the bones of a joint. The illustrated embodiments provide at least one example. In other embodiments, at least one of a cutting guide body, a proximal arm, a distal arm, and a bone engagement surface of a inferior surface of the body is configured to engage a dorsal surface of one or more of a first bone and a second bone. 
     It should be noted that the cutting guide  1900  and/or cutting guide  2200  may be configured to engage with a dorsal surface of one bone (e.g., a first cuneiform  210 ) and a lateral surface of a second bone (e.g., a first metatarsal  230 ) of a joint (e.g., TMT joint  2000 ). For example, where the patient has a hallux valgus condition, the first metatarsal  230  may have rotated about its longitudinal axis  1976 / 2276  such that the lateral surface of the first metatarsal  230  faces dorsal. Advantageously, the present disclosure accounts for this and the cutting guide  1900 / 2200  is configured to contact a dorsal surface on one bone and a lateral surface of the second bone (or proximal surface if the bone is rotated in the other direction). Furthermore, the proximal alignment feature  1980 / 2280  may engage with a dorsal surface of a proximal bone and the distal alignment feature  1990 / 2290  may engage with a dorsal surface of a distal bone, even though the distal bone has rotated. 
     Referring to  FIGS. 20 and 23 , in the illustrated embodiments, the proximal alignment feature  1980 / 2280  and distal alignment feature  1990 / 2290  may be in separate devices rather than being combined in a single device.  FIGS. 20 and 23  show the proximal alignment feature  1980 / 2280  as part of the cutting guide  1900 / 2200 .  FIG. 24A  illustrates a distal alignment feature  1990 / 2290  that is part of a separate device.  FIG. 24A  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIGS. 20, 23  with one embodiment of a pin guide  2400  that includes a distal alignment feature  1990 / 2290 . 
       FIG. 24A  illustrates a perspective view of the first cuneiform  210  and the first metatarsal  230  of  FIG. 23  after resection of the bones. After resection, a surgeon remove the cutting guide  1900 / 2200  by sliding it off of the fasteners  1956  and keep the fasteners  1956  connected to the bones. The fasteners  1956  on the first cuneiform  210  can serve as a proximal alignment feature  1980 / 2280 . The fasteners  1956  on the first metatarsal  230  can serve as a guide for a distal alignment feature  1990 / 2290 . For example, the surgeon can slide pin guide  2400  over the fasteners  1956  on the first metatarsal  230 . The pin guide  2400  can then identify where to position the distal alignment feature  1990 / 2290 . 
     The pin guide  2400  includes a bone attachment feature  2410  realized by a pair of holes  2412  that extend from a superior surface to an inferior surface. Advantageously, the holes  2412  can engage with the fasteners  1956  (which have remained in the bone) used with the cutting guide  1900 / 2200 . 
     The pin guide  2400  also includes a distal alignment feature  1990 / 2290 . In certain embodiments, the distal alignment feature  1990 / 2290  is offset from the bone attachment feature  2410 . In certain embodiments, the bone attachment feature  2410  is offset from the bone attachment feature  2410  by a certain distance that corresponds to a number of degrees of rotation of the first metatarsal  230  from an original position to a new positioned after rotating the first metatarsal  230  about its longitudinal axis  1976 / 2276 . The first metatarsal  230  can be rotated a certain number of degrees about its longitudinal axis  1976 / 2276  in either a clockwise or a counterclockwise direction. Typically, the first metatarsal  230  is rotated counterclockwise to address a condition such as a hallux valgus condition. 
       FIG. 24B  illustrates a diagram representative of a cross-sectional view of a first metatarsal  230  from a proximal base (represented as a circle) looking towards the distal head.  FIG. 24B  illustrates the relationship between the bone attachment feature  2410  and the distal alignment feature  1990 / 2290 . Angle C represents the number of degrees between the first positioned and the second position that the bone will be rotated to once rotated about the longitudinal axis  1976 / 2276 . In certain embodiments, angle C may range between about 0 and about 35 degrees. 
     Referring now to  FIG. 24A , a surgeon may not know per-operatively how much rotation is needed or can be achieved given the condition and anatomy of the patient. Accordingly, the present disclosure may include a number of pin guides  2400  each with a different number of degrees of correction built into the placement of the distal alignment feature  1990 / 2290  relative to the bone attachment feature  2410 . Examples include a 25 degree pin guide  2400 , 30 degree pin guide  2400 , 35 degree pin guide  2400 , 40 degree pin guide  2400 , 10 degree pin guide  2400 , 15 degree pin guide  2400 , and the like. Each pin guide  2400  that provides a different number of degrees of rotation may include a marking that identifies the number of degrees (e.g., “25”, “30”, etc.). Alternatively, or in addition, certain pin guide  2400  may be configured for use on a joint of a left foot versus a right foot. Similarly, such pin guide  2400  may include an indicator of which foot the guide is to be used with (e.g., “Left”, “Right”). Those of skill in the art will appreciate that the degrees for the pin guide  2400  may range from about 2 degrees to about 100 degrees. 
     In the illustrated embodiment, the bone attachment feature  2410  is perpendicular to the first slot  1960 / 2260  and parallel to the distal alignment feature  1990 / 2290  that can be coupled to the first metatarsal  230 . 
     In one embodiment, after a surgeon selects that desired amount of offset by choosing a pin guide  2400  with a desired number of degrees, the surgeon positions the selected pin guide  2400  on the first metatarsal  230  by sliding the holes  2412  over the fasteners  1956 . Placement of the pin guide  2400  positions the distal alignment feature  1990 / 2290  for subsequent rotation of the bone. Next, a surgeon may insert two fasteners  1956  into holes of the distal alignment feature  1990 / 2290 . The fasteners  1956  may mark the position for alignment and sit securely in the bone. 
     Next a surgeon may de-rotate or rotate the first metatarsal  230  for subsequent fusion to the first cuneiform  210 . De-rotation refers to rotation of the first metatarsal  230  about the longitudinal axis  1976 / 2276  such that the first metatarsal  230  assumes a position before the condition presented, for example a hallux valgus condition. As noted de-rotation may mean rotating the first metatarsal  230  counterclockwise. 
       FIG. 24C  shows one way de-rotation may be performed.  FIG. 24C  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 24A  with a pin guide connected. A surgeon may use various ways, devices, or methods to de-rotate the first metatarsal  230 . In one embodiment, the pin guide  2400  may include a coupler, such as a threaded hole  2414  configured to thread onto an end of a handle  2416 . A surgeon may connect the handle  2416  to the pin guide  2400  by way of the threaded hole  2414 . A surgeon can then use the handle  2416  to guide and rotate or de-rotate the first metatarsal  230  into a desired position. In the illustrated embodiment, the surgeon may de-rotate the first metatarsal  230  until the distal alignment feature  1990 / 2290  substantially aligns with the proximal alignment feature  1980 / 2280 . Alternatively, or in addition, the surgeon may rotate the first metatarsal  230  using fasteners  1956  of the distal alignment feature  1990 / 2290  and/or the bone attachment feature  2410 . 
       FIG. 25A  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 23  with one embodiment of a de-rotation handle. As an alternative to using a pin guide  2400  a surgeon may connect a de-rotation handle  2500  to fasteners  1956  of the distal bone attachment feature  1954 / 2254 . The de-rotation handle  2500  may be connected to extend laterally such that once the first metatarsal  230  is de-rotated two more fasteners  1956  can be inserted into the first metatarsal  230  at a position that substantially aligns with the proximal alignment feature  1980 / 2280 . 
       FIG. 25B  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIG. 25A  with the de-rotation handle and first metatarsal rotated. Once the first metatarsal  230  has been de-rotated a surgeon may connect an alignment handle  2510  to fasteners  1956  of the proximal alignment feature  1980 / 2280 . The alignment handle  2510  may include two proximal alignment holes  2512  and two distal alignment holes  2514 . A surgeon may rotate or de-rotate the first metatarsal  230  using the de-rotation handle  2500  until the first metatarsal  230  is in a desired de-rotated/rotated position. Next, a surgeon may slide the proximal alignment holes  2512  over the fasteners  1956  of the proximal alignment feature  1980 / 2280 . The distal alignment holes  2514  may be aligned with the proximal alignment holes  2512 . Next, a surgeon may insert a fasteners  1956  (e.g., K-wire) into the distal alignment holes  2514 . The fasteners  1956  of the distal alignment holes  2514  may serve as the distal alignment feature  1990 / 2290 . Next, the osteotomy may include a final alignment and compression step. 
       FIG. 26  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIGS. 24A, 25A  with a compressor/distractor and cross joint guide. In the illustrated embodiment, a surgeon has removed other instruments such that fasteners  1956  of the proximal alignment feature  1980 / 2280  and fasteners  1956  of the distal alignment feature  1990 / 2290  remain in the bones. Next, the surgeon may couple an active compression instrument  2610  (which may be similar to the exemplary parallel compressor/distractor  1500  or parallel compressor/distractor  1600 ) to the fasteners  1956  by sliding the holes  1502   a,b  over the fasteners  1956  of the proximal alignment feature  1980 / 2280  and the holes  1502   c,d  over the fasteners  1956  of the distal alignment feature  1990 / 2290 . An active compression instrument  2610  refers to any instrument that can compress two or more structures together towards each other or against a stationary object. An “active compression instrument” refers to a mechanical device, apparatus, member, object, body, component, or structure, that is organized, configured, designed, arranged, or engineered to maintain two objects in a compressed state one against the other which may enable a user to perform one or more other operations, method steps, or activities. One example of an active compression instrument is a compressor or an instrument that can function as both a compressor and a distractor. An active compression instrument  2610  may be configured to only provide a compression feature. Alternatively, or in addition, an active compression instrument  2610  may be configured to provide both a compression feature and a distraction feature. The distraction feature is a feature the distracts or separates at least two structures. 
     According to certain methods, a surgeon may next distract the joint in order to prepare surfaces for fusion. The surgeon may slide holes  1502   a,b  over fasteners  1956  and holes  1502   c,d  over fasteners  1956 . The surgeon activates the parallel compressor/distractor  1500  to distract the first metatarsal  230  relative to the first cuneiform  210 . Connecting the parallel compressor/distractor  1500  may perform final alignment of the first cuneiform  210  and first metatarsal  230 . Once distracted, the surgeon may remove intruding soft tissue and may fenestrate and/or abrade the cut surfaces of the two bones to encourage fusion and/or osteointegration. 
     Next, the surgeon may use the parallel compressor/distractor  1500  to compress the two bones together at the newly formed cut surfaces. This causes a desired rotation and translation of the first metatarsal  230  relative to the first cuneiform  210 . This forces the cut surfaces (or faces) of the two bones to become parallel. Advantageously, the cut surfaces of the two bones can be forced to become parallel because the position, orientation, and angles of the fasteners  1956  of either, or both, of the proximal alignment feature  1980 / 2280  and distal alignment feature  1990 / 2290  can be predefined and customized for each patient when the cutting guide  1900 / 2200  is fabricated. This alignment enables parallel compression of the two bones together using the parallel compressor/distractor  1500  to provide active compression. Parallel active compression enables more effective compression of the two bones together. The parallel compressor/distractor  1500  is activated such that the first cuneiform  210  and the first metatarsal  230  are pressed together against each other. 
     Next, various forms of fixation may be used to complete the fusion of the two bones.  FIG. 27  illustrates a perspective view of the first cuneiform and the first metatarsal of  FIGS. 24A, 25A  with a parallel compressor/distractor  1500  and fastener(s). In one embodiment, a surgeon may slide the cross joint guide  1604  over the fasteners  1956  of the distal alignment feature  1990 / 2290  and use the holes  1608  to deploy fasteners such as K-wires or bone screws across the joint to respectively, temporarily or permanently fuse the joint. 
     Alternatively, or in addition, the surgeon may leave the parallel compressor/distractor  1500  connected and actively applying a compressive force to press the bones together while another kind of fastener  2710 , such as a bone plate. The fastener  2710  may be deployed with one or more bone screws into the bones to connect the first metatarsal  230  to the first cuneiform  210 . Advantageously, the fastener  2710  can be deployed which the bones are under active compression. This can promote osteointegration and fusion of the bones to close the joint. With the fastener  2710  deployed a surgeon may release, and remove, the parallel compressor/distractor  1500 . This may complete the osteotomy procedure with the remains steps being closing the incision(s) and preparing the patient for recovery. 
       FIG. 28  illustrates a perspective view of an exemplary system  2800  for correcting a condition in accordance with one embodiment. The system  2800  includes a cut guide  2810 , a first metatarsal alignment feature  2820 , and a compressor/distractor  2830 . 
     In certain embodiments, the cut guide  2810  may be a patient specific instrument, a patient specific cut guide. In certain embodiments, the cut guide  2810  is fabricated for a particular joint, of a particular patient, and/or to address a particular condition. Various example cut guides such as cut guide  300 , cut guide  700 , cut guide  1043 , cut guide  1200 , cutting guide  1900 , cut guide  2200 , or the like may serve as the cut guide  2810  of the system  2800 . The cut guide  2810  may include a first guide feature configured to define a first cut surface configured for resection of a first metatarsal of a patient. First slot  1960  and/or first slot  2260  may serve as one example of the first guide feature. The cut guide  2810  may include a second guide feature configured to define a second cut surface configured for resection of a medial cuneiform of a patient. Second slot  1970  and/or second slot  2270  may serve as one example of the second guide feature. The cut guide  2810  may include an inferior side comprising a bone engagement surface shaped to match a first surface of the first metatarsal and a second surface of the medial cuneiform. Inferior side  1922  and/or bone engagement surface  1924  or inferior side  2222  and/or bone engagement surface  2224  may serve as one example of the inferior side and bone engagement surface. In one embodiment, the cut guide  2810  may include a medial cuneiform alignment feature coupled to the medial cuneiform. The proximal alignment feature  1980  and/or the proximal alignment feature  2280  may serve as the medial cuneiform alignment feature. The first guide feature and/or the second guide feature of the cut guide  2810  may be configured based on patient imaging data such that fusion of the first metatarsal at the first cut surface to the medial cuneiform at the second cut surface mitigates the condition. In certain embodiments, the cut guide  2810  is fabricated for single use with a single patient and on a left or a right extremity of the patient. 
     The first metatarsal alignment feature  2820  may take the form of various devices. In one embodiment, the first metatarsal alignment feature  2820  may include the distal alignment feature  1990  and/or the distal alignment feature  2290  of a pin guide  2400  or one or more fasteners  1956  placed by a surgeon or placed using one or more of a de-rotation handle  2500  and/or alignment handle  2510 . The pin guide  2400  may position a plurality of alignment pins such that the first metatarsal  230  can be rotated to align the pins and rotate the first metatarsal  230  through a desired rotation angle about the first metatarsal  230  longitudinal axis. 
     The system  2800  may include a plurality of pin guides  2400  each of a different size, such as different degrees of offset angle (angle C), different sizes based on gender, and different sizes or configurations based on which extremity is involved. Advantageously, the first metatarsal alignment feature  2820  may be independent of the cut guide  2810 . The independence provides flexibility relating to de-rotation of the first metatarsal. 
     The compressor/distractor  2830  may include the parallel compressor/distractor  1500  and/or the parallel compressor/distractor  1600 . The compressor/distractor  2830  can engage the medial cuneiform alignment feature and the first metatarsal alignment feature and compress a first cut surface of the first metatarsal against a second cut surface of the medial cuneiform. The medial cuneiform alignment feature and the first metatarsal alignment feature may be substantially aligned prior to connecting the compressor/distractor  2830 . Connecting the compressor/distractor  2830  may provide final alignment of the medial cuneiform alignment feature and the first metatarsal alignment feature. In certain embodiments, the medial cuneiform alignment feature and the first metatarsal alignment feature may not be aligned with each other. Instead, legs of the compressor/distractor  2830  may be configured to engage the unaligned medial cuneiform alignment feature and first metatarsal alignment feature. The compressor/distractor  2830  may also include a compression feature but not a distractor feature. In certain embodiments, different sizes of compressor/distractor  2830  may be included to different sizes of patients. 
     In certain embodiments, the compressor/distractor  2830  includes legs that are closer to each other at distal end of each leg than at a proximal end of each leg. The legs  1504 / 1506  and toes  1508 / 1510  of the compressor/distractor  1500 / 2830  are one example of such an embodiment. Advantageously, the cut guide  2810  can be customized for a specific patient. In certain embodiments, this means that the position and orientation of one or more of the first guide feature, second guide feature, bone engagement surface, first bone attachment feature, second bone attachment feature, first alignment feature, and/or second alignment feature, can be determined based on patient imaging data and can be engineered and fabricated to address a specific condition for a particular patient. For example, the position and orientation of one or more of the first guide feature, second guide feature may be such that a planter edge of a first cut surface of a first metatarsal  230  contacts a corresponding planter edge of a second cut surface of a first metatarsal  230  as the two cut surfaces are brought together to fuse the joint. The compressor/distractor  1500 / 2830  may translate and/or rotate one or the other or both of the first metatarsal  230  and first cuneiform  210  such that the two cut surfaces. In this manner, the cut guide  2810  and/or the system  2800  avoids a plantar gap between the two bones. Avoiding a plantar gap can be a factor in a successful fusion that also avoids non-union. 
       FIG. 29  is a flow chart diagram of one example method  2900  for making a patient specific cutting guide according to one embodiment. Prior to steps of the method  2900 , a bone model (also referred to as CAD model above) or one or more bones of a patient is generated. The bone model may be generated using medical imaging of a patient&#39;s foot and may also be referred to as an anatomic model. The medical imaging image(s) may be used by computing devices to generate patient imaging data. The patient imaging data may be used to measure and account for orientation of one or more structures of a patient&#39;s anatomy. In certain embodiments, the patient imaging data may serve or be a part of anatomic data for a patient. 
     A bone model or anatomic model of a patient&#39;s body or body part(s) may be generated by computing devices that analyze medical imaging images. Structures of a patient&#39;s body can be determined using a process called segmentation. In certain embodiments, the patient imaging data maybe gathered from the patient as the patient is not placing their weight on one or more feet. Alternatively, or in addition, in certain embodiments, the patient imaging data maybe gathered from the patient as the patient is placing their weight on one or more feet. Such imaging may be referred to as weight-bearing patient imaging data. For example in one embodiment, the bone model is derived from patient imaging data generated while the patient placed their weight on at least one joint involved in the osteotomy procedure. 
     Generally, an osteotomy procedure is not done while a patient places their weight on one or more feet involved in the procedure. Thus, a surgeon can not intraoperatively determine how much correction of bone positioning and/or rotation may be desired to correct a condition such as a hallux valgus. However, because the present disclosure can be used to generate patient specific instrumentation from weight-bearing patient imaging data, the present disclosure can provide instruments such as cut guide, pin guide, bone engagement surface  1924 / 2224 , parallel compressor/distractor, or the like that account for positions and configurations of the patient&#39;s bones while bearing the weight of the patient. Advantageously, using weight-bearing patient imaging data can provide for more successful procedures and more long term and lasting correction of conditions for the patient. 
     In one embodiment, the method  2900  begins after a bone model of a patient&#39;s body or body part(s) is generated. In a first step  2910 , bone model of one or more bones of a patient based on the condition and/or the bone model is accessed. Next, the method  2900  defines  2920  one or more guide features of a preliminary cutting guide model for an osteotomy procedure, the preliminary cutting guide model comprising a superior surface and an inferior surface. Next, the method  2900  proceeds by defining  2930  at least a portion of the inferior surface of the preliminary cutting guide model according to a topographical surface of at least one bone of the bone model such that the inferior surface substantially matches a contour of the topographical surface. In certain embodiments, the method  2900  may also include a step of defining one or more alignment features of the preliminary cutting guide model for the osteotomy procedure. After step  2930 , the preliminary cutting guide model is configured for fabrication of a patient specific cutting guide corresponding to the preliminary cutting guide model. After step  2930 , the method  2900  may end. 
     “Topographical” refers to the physical distribution of parts, structures, or features on the surface of, or within, an organ or other anatomical structure, or organism. (Search “define topographical” on google.com. Oxford Languages, Copyright 2022. Oxford University Press. Web., Modified. Accessed 15 Feb. 2022.) 
     In one aspect, the preliminary cutting guide may be used, as-is, without any further changes, modifications, or adjustments and thus become a patient specific cutting guide. In another aspect, the preliminary cutting guide may be modified, adjusted, or configured to more specifically address the goals, objectives, or needs of a patient or a surgeon and by way of the modifications become a patient specific cutting guide. 
     The patient specific cutting guide can be used by a user, such as a surgeon, to guide making one or more resections of a structure, such as a bone for a procedure. Accordingly, a preliminary cutting guide model can be used to generate a patient specific cutting guide model. The patient specific cutting guide model may be used in a surgical procedure to address, correct, or mitigate effects of the identified deformity and may be used to generate a patient specific cutting guide that can be used in a surgical procedure for the patient. 
       FIGS. 30A-30C  illustrates perspective views of an exemplary preliminary cutting guide model modified in accordance with one embodiment for use as a patient-specific cutting guide. In certain embodiments, steps of the method  2900  may include additional steps that add to or expand upon steps of the method  2900 . 
     For example, accessing  2910  a bone model of one or more bones of a patient based on the condition and/or the bone model may include additional steps. For example, the bone model may include a first modeled bone (not shown in  FIG. 30A ) and a second modeled bone (not shown in  FIG. 30A ) of a joint of the patient and the bone model may be modified such that the first modeled bone (e.g., a first metatarsal  230 ) is rotated about a longitudinal axis of the first modeled bone from a first position to a second position.  FIG. 30A  illustrates one example of a preliminary cutting guide model  3000 . 
     Next, a first cut surface in the first modeled bone is defined that is perpendicular to the longitudinal axis of the first modeled bone. The first cut surface may be defined using a first guide feature  3060  and may be predefined in a preliminary cutting guide model  3000 . In certain embodiments, the first cut surface may be formed during the procedure on a patient&#39;s bone by a surgeon cutting using a first guide feature  3060 . The first guide feature  3060  may be defined in the preliminary cutting guide model  3000  such that cutting using the first guide feature  3060  will form the first cut surface. The first guide feature  3060  may include a slot formed in the preliminary cutting guide model  3000  that is configured to guide formation of the first cut surface. 
     In one embodiment, the preliminary cutting guide model  3000  may originally include a predefined first guide feature  3060  that is aligned perpendicular to two or more holes  3050  of a distal bone attachment feature  3054 . It should be noted that the preliminary cutting guide model  3000  of  FIG. 30A  does not include a second guide feature and/or a second hole  3050  because the orientation and position of the second guide feature and/or a second hole  3050  has not yet been determined or defined. In certain embodiments, the preliminary cutting guide model  3000  may be selected from a repository of template cutting guide models. Each template cutting guide model may be configured for an osteotomy procedure configured to correct one of a plurality of conditions. 
     Next, as part of accessing  2910  a bone model, a first angle for a second cut surface of the second modeled bone may be defined. The first angle may be measured relative to the first cut surface and may extend inferiorly away from the first cut surface.  FIG. 19D  illustrates one example of the first angle by way of angle A. Next, a second angle for the second cut surface of the second modeled bone may be defined. The second angle may be measured relative to the first cut surface and configured to mitigate the condition.  FIG. 19H  illustrates one example of the first angle by way of angle B. 
     Next, as part of accessing  2910  a bone model, the bone model of the first modeled bone may be modified to include the first cut surface and the second modeled bone may be modified to include the second cut surface. In addition, one or more guide members of the preliminary cutting guide model  3000  are configured and positioned to enable a surgeon to form the first cut surface and the second cut surface. 
     Accordingly, referring to  FIG. 30B , a second guide feature  3070  in the form of a second slot may be defined in the preliminary cutting guide model  3000  and configured to guide formation of a second cut surface of a second bone of the patient corresponding to the second modeled bone. The first guide feature  3060  and second guide feature  3070  are positioned in the preliminary cutting guide model  3000  such that fixing the first cut surface of the first bone to the second cut surface of the second bone mitigates the condition. Note that the preliminary cutting guide model  3000  includes both the first guide feature  3060  and the second guide feature  3070 . In the illustrated embodiment, the second guide feature  3070  is oriented and positioned for formation of the second cut surface. In addition, a second hole  3050  is defined in the proximal arm  3030 . The second hole  3050  aligns with a first hole  3050  of the proximal alignment feature  3080  in addition the holes of the proximal alignment feature  3080  are perpendicular to the second guide feature  3070 . 
     In the illustrated embodiment, of  FIGS. 30A, 30B , an inferior side, also referred to as the bone engagement surface of the preliminary cutting guide model  3000  has a squared and boxy configuration because the inferior side for the preliminary cutting guide model  3000  has not yet been defined.  FIG. 30C  illustrates an inferior side  3022 , or bone engagement surface  3024  that has been defined to match the contour of bones of the patient based on patient imaging data. The modified preliminary cutting guide model  3000  of  FIG. 30C  is ready to be manufactured, for example, using additive manufacturing. 
       FIG. 31  is a flow chart diagram of one example method  3100  for using a patient specific cutting guide according to one embodiment to mitigate a condition present in a patient. Before the method  3100  begins a surgeon may obtain a patient specific cut guide and/or one or more other instruments that may be patient specific or may be configured for use with most patients. 
     The method begins and the surgeon positions  3102  a patient specific cut guide across of joint of two bones of a patient. Next, the surgeon may secure  3104  the patient specific cut guide to the bones of the joint using pins (e.g., K-wires). Next, the surgeon may resect  3106  the articular surface of both bones of the joint. Next, the surgeon may remove  3108  the patient specific cut guide while leaving one or more pins in place on the bones. Pins left in place may include pins that are part of the proximal bone attachment feature  2252  and/or the distal bone attachment feature  2254 . Next, the surgeon may de-rotate  3110  one or more bones of the joint. Next, the surgeon may connect  3112  an active compression instrument to pins on each bone of the joint. Next, the surgeon may compress  3114  the two bones of the joint together. Next, the surgeon may deploy  3116  fasteners across the joint. The fasteners may be temporary fasteners such as K-wires or bone screws or permanent fasteners such as a bone plate and bone screws. 
     Those of skill in the art will appreciate that method  3100  is one of many that may be used to address a condition of the patient using the apparatuses, devices, methods, features, and aspects of the present disclosure. 
     Any methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. 
     Reference throughout this specification to “an embodiment” or “the embodiment” means that a particular feature, structure or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment. 
     Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than those expressly recited in that claim. Rather, as the following claims reflect, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. Thus, the claims following this Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment. This disclosure includes all permutations of the independent claims with their dependent claims. 
     Recitation in the claims of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. Elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. § 112 Para. 6. It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles set forth herein. 
     While specific embodiments and applications of the present disclosure have been illustrated and described, it is to be understood that the scope of this disclosure is not limited to the precise configuration and components disclosed herein. Various modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems of the present disclosure set forth herein without departing from it spirit and scope.