Patent Publication Number: US-2021186530-A1

Title: Orthopedic surgical guide

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 12/711,307, which was filed on Feb. 24, 2010 claiming priority to U.S. Provisional Patent Application No. 61/154,845 filed on Feb. 24, 2009, and claims priority to U.S. Provisional Patent Application No. 61/425,054 filed on Dec. 20, 2010 and to U.S. Provisional Patent Application No. 61/482,657 filed on May 5, 2011, the entireties of which are herein incorporated by reference. 
    
    
     FIELD OF DISCLOSURE 
     The disclosed system and method generally relate to surgical guides. More specifically, the disclosed system and method relate to surgical guides for orthopedic procedures involving an ankle. 
     BACKGROUND 
     Total joint replacement prostheses typically include a specially designed jig or fixture to enable a surgeon to make accurate and precise bone resections in and around the joint being prepared to accept the prosthesis. The ultimate goal with any total joint prosthesis is to approximate the function and structure of the natural, healthy structures that the prosthesis is replacing. Should the prosthesis not be properly attached to the joint, i.e., an ankle or knee, the misalignment could result in discomfort to the patient, gait problems, or degradation of the prosthesis. 
     Many surgical procedures employ the use of intra-operative fluoroscopy to check the alignment of the intramedullary cavities that are prepared to receive the joint replacement prosthesis. However, the use of intra-operative fluoroscopy in the operating room has several drawbacks. One such drawback is that the use of fluoroscopy to check the alignment of intramedullary cavities formed during surgery increases the overall length of the surgical procedure as time is taken to acquire and evaluate the fluoroscopic images. Long surgery times lead to increased tourniquet time forth patient and therefore may increase recovery time. 
     Another drawback of fluoroscopy is exposing the patient and others in the operating room to the ionized radiation. For example, the U.S. Food and Drug Administration (“FDA”) has issued several articles and public health advisories concerning the use of the fluoroscopy during surgical procedures. Consequently, even though steps are taken to protect the patient and other from the ionized radiation, it is virtually impossible to eliminate all risk associated with the ionized radiation. 
     SUMMARY 
     A system for establishing an intramedullary path is disclosed that includes a body sized and configured to be received within a resected bone space. The body defines a first aperture that extends through the body and is sized and configured to receive a surgical tool therethrough. A first bone engaging structure extends from the body in a first direction and includes a first surface that is complementary to a surface topography of a first bone. When the first surface of the bone engaging structure engages the surface topography of the first bone to which the first surface is complementary, an axis defined by the first aperture is substantially collinear with a mechanical axis of the first bone. 
     Also disclosed is a system for establishing an intramedullary path that includes a drill guide mount having a body sized and configured to be received within a resected bone space. The body defines a first aperture that extends through the body. A first bone engaging structure extends from the body in a first direction and includes a first surface that is complementary to a surface topography of a first bone. A drill guide is sized and configured to be received within the first aperture defined by the body of the drill guide mount. The drill guide defines a second aperture sized and configured to receive the surgical tool therethrough. When the first surface of the bone engaging structure engages the surface topography of the bone to which the first surface is complementary, an axis defined by the second aperture is substantially collinear with a mechanical axis of the first bone. 
     A method is also disclosed that includes inserting a drill guide into an aperture defined by a drill guide mount. The drill guide mount includes a first bone engaging structure extending from a body of the drill guide mount in a first direction and having a first surface that is complementary to a surface topography of a first bone. The drill guide mount and the drill guide disposed within the first aperture of the drill guide mount are inserted into a resected bone space such that the first surface of the bone engaging structure correspondingly engages the first bone. A surgical tool is extended through a second aperture defined by the drill guide to establish an intramedullary channel within the first bone that is substantially collinear with a mechanical axis of the first bone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
         FIG. 1  illustrates the bones of a human foot and ankle; 
         FIGS. 2A and 2B  are schematic representations of a scanned image of a human foot and ankle joint; 
         FIG. 3  is a perspective view of tibial and talar resection guides located upon portions of a tibia and a talus; 
         FIG. 4  is an exploded perspective view of a tibial cutting guide mount and tibial resection guide; 
         FIG. 5  is a perspective view of a tibial cutting guide disposed within a tibial cutting guide mount located on an inferior portion of a tibia; 
         FIG. 6  is a front elevational view of a tibial cutting guide disposed within a tibial cutting guide mount located on an inferior portion of a tibia; 
         FIG. 7  is a side elevational view of a tibial cutting guide disposed within a tibial cutting guide mount located on an inferior portion of a tibia during resection of the tibia; 
         FIG. 8  is a schematic representation of a resected tibia following application and use of the tibial cutting guide and tibial cutting guide mount; 
         FIG. 9  is a perspective view of a talar cutting guide disposed within a talar cutting guide mount; 
         FIG. 10  is an exploded perspective view of the talar cutting guide mount and the talar cutting guide illustrated in  FIG. 9 ; 
         FIG. 11  is a perspective view of the talar cutting guide disposed within the talar cutting guide mount located on a superior portion of a talus; 
         FIG. 12  is a front elevational view of the talar cutting guide disposed within the talar cutting guide mount located on a superior portion of a talus; 
         FIG. 13  is a side perspective view of the talar cutting guide disposed within the talar cutting guide mount located on a superior portion of a talus during resection of the talus; 
         FIG. 14  is a schematic representation of a resected talus following application and use of the talar cutting guide and talar cutting guide mount; 
         FIG. 15  is a schematic representation of a resected joint space following application and use of the talar and tibial cutting guide mounts and cutting guides; 
         FIG. 16  is a perspective view of one example of a custom tibial drill guide mount; 
         FIG. 17  is a front elevational view of the tibial drill guide mount illustrated in  FIG. 16 ; 
         FIG. 18  is a rear elevation view of the tibial drill guide mount illustrated in  FIG. 16 ; 
         FIG. 19  is a bottom elevational view of the tibial drill guide mount illustrated in  FIG. 16 ; 
         FIG. 20  is a top elevational view of the tibial drill guide mount illustrated in  FIG. 16 ; 
         FIG. 21  is a perspective view of one example of a tibial drill guide; 
         FIG. 22  is a side elevational view of the tibial drill guide illustrated in  FIG. 21 ; 
         FIG. 23  is a top elevational view of the tibial drill guide illustrated in  FIG. 21 ; 
         FIG. 24  is an exploded perspective view of the tibial drill guide mount and the tibial drill guide; 
         FIG. 25A  is a side elevational view of the tibial drill guide disposed within the tibial drill guide mount being inserted into resected joint space; 
         FIG. 25B  is a perspective view of the assemblage of the tibial drill guide mount and tibial drill guide disposed within the resected joint space; 
         FIG. 25C  is a perspective view of the assembly of the tibial drill guide mount and tibial drill guide disposed and pinned within the resected joint space; 
         FIG. 26  is a perspective view of one example of an alignment tool; 
         FIG. 27  is an exploded perspective view of the alignment tool illustrated in  FIG. 26 ; 
         FIGS. 28A and 28B  illustrate the relative movement permitted between each of the components of the alignment tool illustrated in  FIG. 26 ; 
         FIG. 29  is a perspective view of one example of an adapter bar for coupling the assemblage of the tibial drill guide mount and tibial drill guide to the alignment tool; 
         FIG. 30  is a perspective view of the adapter bar coupled to the assemblage of the tibial drill guide mount and tibial drill guide and to the alignment tool; 
         FIG. 31  is a top isometric view of another example of an alignment tool/foot holder assembly for use with a tibial drill guide mount and tibial drill guide; 
         FIG. 32  is a bottom isometric view of the alignment tool/foot holder assembly illustrated in  FIG. 31 ; 
         FIG. 33  is an elevational front view of the alignment tool/foot holder assembly illustrated in  FIG. 31 ; 
         FIG. 34  is an elevational side view of the alignment tool/foot holder assembly illustrated in  FIG. 31 ; 
         FIG. 35  is a top isometric view of another example of an alignment tool/foot holder assembly for use with the tibial drill guide mount and tibial drill guide; 
         FIG. 36  is a top elevational view of the alignment tool/foot holder assembly illustrated in  FIG. 35 ; 
         FIG. 37  is an elevational front view of the alignment tool/foot holder assembly illustrated in  FIG. 35 ; 
         FIG. 38  is an elevational side view of the alignment tool/foot holder assembly illustrated in  FIG. 35 ; 
         FIG. 39  is a perspective view of another example of a tibial cutting guide mount; 
         FIG. 40  is a front side elevational view of the tibial cutting guide mount illustrated in  FIG. 39 ; 
         FIG. 41  is a side elevational view of the tibial cutting guide mount illustrated in  FIG. 39 ; 
         FIG. 42  is a top side view of the tibial cutting guide mount illustrated in  FIG. 39 ; 
         FIG. 43  is a bottom side view of the tibial cutting guide mount illustrated in  FIG. 39 ; 
         FIG. 44  is a perspective view of a tibial drill guide cartridge for use with the tibial drill guide mount illustrated in  FIG. 39 ; 
         FIG. 45  is a front end view of the tibial drill guide cartridge illustrated in  FIG. 44 ; 
         FIG. 46  is a bottom side plan view of the tibial drill guide cartridge illustrated in  FIG. 44 ; 
         FIG. 47  is a side view of the tibial drill guide cartridge illustrated in  FIG. 44 ; 
         FIG. 48  is an exploded perspective view of a mounting plate and dowel pins configured to for use with the tibial drill guide mount illustrated in  FIG. 39 ; 
         FIG. 49  is a partially exploded perspective view of a mounting plate and dowel pins configured to for use with the tibial drill guide mount illustrated in  FIG. 39 ; 
         FIG. 50  is a partially exploded perspective view of a mounting plate, dowel pins, and tibial drill guide mount configured to receive a tibial drill guide cartridge in accordance with  FIG. 44 ; 
         FIG. 51  is a perspective view of the tibial drill guide mount, tibial drill guide cartridge, dowel pins, and mounting plate assembled together; 
         FIG. 52  is a side view of the assembly illustrated in  FIG. 51 ; 
         FIG. 53  is a top side plan view of the assembly illustrated in  FIG. 51 ; 
         FIG. 54  is a bottom side plan view of the assembly illustrated in  FIG. 51 , 
         FIG. 55  is a perspective view of a foot holder assembly for use with the assembly illustrated in  FIG. 51 ; 
         FIG. 56  is a perspective view of a pivoting arrangement used to secure the assembly illustrated in  FIG. 51  to the foot holder assembly; 
         FIG. 57  is a top side plan view of the foot holder assembly illustrated in  FIG. 55 ; 
         FIG. 58  is a side view of the foot holder assembly illustrated in  FIG. 55 ; 
         FIG. 59  is an opposite side view of the foot holder assembly illustrated in  FIG. 55 ; 
         FIG. 60  is a rear end view of the foot holder assembly illustrated in  FIG. 55 ; 
         FIG. 61  is a front end view of the foot holder assembly illustrated in  FIG. 55 ; 
         FIG. 62  is a perspective view of a drill being extended through the foot holder assembly and tibial drill guide. 
     
    
    
     DETAILED DESCRIPTION 
     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. The drawing figures are not necessarily to scale and certain features may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. When only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures. 
     The disclosed systems and methods advantageously utilize custom manufactured surgical instruments, guides, and/or fixtures that are based upon a patient&#39;s anatomy to reduce the use of fluoroscopy during a surgical procedure. In some instances, the use of fluoroscopy during a surgical procedure may be eliminated altogether. The custom instruments, guides, and/or fixtures are created by imaging a patient&#39;s anatomy with a computer tomography scanner (“CT”), a magnetic resonance imaging machine (“MRI”), or like medical imaging technology prior to surgery and utilizing these images to create patient-specific instruments, guides, and/or fixtures. 
     Although the following description of the custom patient-specific instruments are described with respect to a foot  10  and ankle  12  ( FIG. 1 ), one skilled in the art will understand that the systems and methods may be utilized in connection with other joints including, but not limited to, knees, hips, shoulders, and the like. As shown in  FIG. 1 , a typical human foot  10  includes an ankle joint  12  formed between a talus  14 , which is disposed on a calcaneus  20 , and a tibia  16  and fibula  18 . 
     A CT or MRI scanned image or series of images may be taken of a patient&#39;s ankle  12  (or other joint) and then converted from, e.g., a DICOM image format, to a solid computer model of the ankle including the calcaneus, talus, tibia, navicular, and fibula to determine implant alignment, type, and sizing using specialized modeling methods that are often embodied in computer software. Computer generated solid models that are derived from the data of the CT or MRI scan image will often include precise and accurate information regarding the surface contours surrounding the structures that have been imaged, e.g., the surface topography of the bones or contour of fascia that have been imaged. It will be understood that by surface topography it is meant the location, shape, size and distribution of surface features such as concavities and prominences or the like. 
     The methods disclosed in U.S. Pat. No. 5,768,134, issued to Swaelens et al., which is incorporated by reference herein in its entirety, have been found to yield adequate conversions of data of CT or MRI scan images to solid computer models. In some embodiments, images are made of a foot  10 , i.e., the calcaneus  20 , talus  14 , tibia  16 , and fibula  18  of a patient using a CT or MRI machine, or other digital image capturing and processing unit as is understood by one skilled in the art. The image data is processed in a processing unit, after which a model  50  is generated using the processed digitized image data as illustrated in  FIGS. 2A and 2B . 
     Interactive processing and preparation of the digitized image data is performed, which includes the manipulation and introduction of additional extrinsic digital information, such as, predefined reference locations  52  for component positioning and alignment so that adjustments to the surgical site  54 , that will require resection during surgery, may be planned and mapped onto computer model  50  ( FIGS. 2A and 2B ). After the interactive processing of the digitized image data, it is possible to go back to original CAD data to obtain a higher resolution digital representation of the patient specific surgical instruments, prostheses, guides, or fixtures so as to add that digital representation to the patient&#39;s image data model. 
       FIG. 3  illustrates a pair of custom cutting guides for an ankle replacement surgery including a tibial resection guide mount  100  and a talar resection guide mount  102 , which are formed and mounted to the patient&#39;s lower tibia  16   a  and upper talus  14   a.  A custom tibial drill guide mount  200  ( FIGS. 16-20 ) is also formed and configured to be received within ankle space created by using the custom tibial and talar resection guide mounts  100 ,  102 . Although custom cutting guides are described for preparing a patient&#39;s talus, tibia, and femur, one skilled in the art will understand that other cutting guides may be implemented and that custom guides may be created for other joints including, but not limited to, the knee, hip, shoulder, or other joint. 
     Tibial resection guide mount  100  illustrated in  FIG. 3  is formed from a resilient polymer material of the type that is suitable for use in connection with stereo lithography, selective laser sintering, or like manufacturing equipment. Resection guide mount  100  includes a unitary body including a cruciform tibial yolk  104  projecting upwardly from a base  106  that further defines a guide receptacle recess  108  as best seen in  FIG. 4 . Cruciform yolk  104  includes a pair of spaced apart arms  110 ,  112  that project outwardly from a central post  114 . Arms  110 ,  112  and central post  114  each have a conformal bone engaging surface  116  that is complementary to the contours of a corresponding portion of the patient&#39;s lower tibia  16   a  as illustrated in  FIG. 7 . Through the previously discussed imaging operations, conformal bone engaging surfaces  116  of arms  110 ,  112  and central post  114  are configured for complementary matching with anatomical surface features of a selected region of the patient&#39;s natural bone. For tibial resection guide mount  100 , the selected bone region comprises the lower surfaces of the patient&#39;s tibia  16   a.    
     As best seen in  FIGS. 3-5 , a pilot block  118  projects outwardly from central post  114 , adjacent to the intersection of arms  110 , 112 . A support block  120  ( FIG. 4 ) is located on base  106  in spaced relation to pilot block  118 . Guide receptacle recess  108  is defined by a pair of wings  122 , 124  that extend outwardly from either side of central post  114  in opposite directions on base  106 , with support block  120  located between them. Each wing  122 ,  124  includes a respective pylon  126  projecting outwardly from base  106  so as to provide lateral support for tibial resection guide  132  ( FIGS. 4 and 5 ). An elongate slot  128  is defined transversely in a central portion of base  106  below pilot block  118 , but above support block  120 . Each wing  122 ,  124  also defines a respective slot  130  that is oriented at an angle relative to central post  114 . In some embodiments, slots  130  are disposed at a non-perpendicular angle relative to central post  114 , although one skilled in the art will understand that slots  130  may be disposed at perpendicular angles with respect to the direction in which central post  114  extends. Slots  128  and  130  are sized and shaped to allow a typical surgical saw  60  ( FIG. 7 ) of the type often used for bone resection, to pass through from a correspondingly positioned and sized slot in resection guide  132  without contact, or with only incidental contact with resection guide mount  100 . 
     Referring again to  FIG. 4 , tibial resection guide  132  includes a pair of arms  134  that project downwardly and outwardly in diverging angular relation from the ends of a bridge beam  136 . The shape of tibial resection guide  132  is complementary to the shape of guide receptacle recess  108  as defined by the inwardly facing surfaces of pilot block  118 , support block  120 , and pylons  126 . Bridge beam  136  defines an elongate slot  138  that aligns with slot  128  when tibial resection guide is coupled to and supported by resection guide mount  100 . Arms  134  each define a respective slot  140  that align with a respective slot  130 . 
     The inwardly facing surfaces  142  of pilot block  118 , support block  120 , and pylons  126 , that together define guide receptacle recess  108 , have a shape that is complementary to the outer profile of tibial resection guide  132 . Guide receptacle recess  108  is sized so as to accept tibial resection guide  132  with a “press-fit”. By press-fit it should be understood that the inwardly facing surfaces  142  of pilot block  118 , support block  120 , and pylons  126  are sufficiently resilient to deflect or compress elastically so as to store elastic energy when tibial resection guide  132  is pushed into guide receptacle recess  108 . Of course, it will also be understood that tibial resection guide  132  will have an outer peripheral shape that is complementary to the circumferential shape of guide receptacle recess  108 , but slightly larger in size, for press-fit embodiments. Also, tibial resection guide  132  may be retained within guide receptacle recess  108  by only frictional engagement with the inwardly facing surfaces of pilot block  118 , support block  120 , and pylons  126 . In some embodiments, tibial resection guide  132  can simply slide into guide receptacle recess  108  without operative contact or only incidental engagement with the inwardly facing surfaces of pilot block  118 , support block  120 , and pylons  126 . 
     Referring now to  FIGS. 9 and 10 , a talar resection guide mount  102  is formed from a resilient polymer material of the type that is suitable for use in connection with stereo lithography, selective laser sintering, or the like manufacturing equipment, e.g., a polyamide powder rapid prototype material is suitable for use in connection with selective laser sintering. Talar resection guide mount  102  also includes a conformal bone engaging surface  144  that is complementary to the contours of a corresponding portion of the patient&#39;s upper talus  14   a  ( FIGS. 11 and 13 ). Through the previously discussed imaging operations, conformal bone engaging surface  144  of talar resection guide mount  102  is configured for complementary matching with anatomical surface features of a selected region of the patient&#39;s natural bone. For talar resection guide mount  102 , the selected bone region comprises the outer, upper surfaces of the patient&#39;s talus. 
     Talar resection guide mount  102  comprises a unitary block that defines a central guide receptacle recess  146  and a pair of through-bores  148  ( FIG. 10 ). Guide receptacle recess  146  is defined by the inwardly facing surfaces  150  of a pair of wings  152 ,  154  that project outwardly, in opposite directions from a base  156 . Each wing  152 , 154  includes a pylon  158  projecting upwardly to support guide housing  160  such that an elongate slot  162  is defined within base  156  and below guide housing  160  ( FIGS. 10 and 11 ). Slot  162  is sized and shaped to allow a typical surgical saw  60 , of the type often used for bone resection, to pass through from a correspondingly positioned and sized slot  164  in talar resection guide  166  without contact, or with only incidental contact with talar resection guide locator  102  ( FIGS. 11 and 13 ). An annular wall  168 , having a shape that is complementary to the outer profile of talar resection guide  166 , projects outwardly in substantially perpendicular relation to a back wall and so as to further defines guide receptacle recess  146 . 
     Still referring to  FIGS. 9 and 10 , talar resection guide  166  includes a pair of confronting, parallel plates  170 ,  172  that define elongate slot  164  between them, and are joined to one another at their ends by wings  174 . In this way, the shape of talar resection guide  166  is complementary to the shape of guide receptacle recess  146  as defined by the inwardly facing surfaces  150  of wings  152 ,  154 , base  156 , and pylons  158 . Guide receptacle recess  146  is sized so as to accept talar resection guide  166  with a press-fit. Of course, it will also be understood that talar resection guide  166  will have an outer peripheral shape that is complementary to the circumferential shape of guide receptacle recess  146 , but slightly larger in size, for press-fit embodiments. Also, talar resection guide  166  may be retained within guide receptacle recess  146  by only frictional engagement with the inwardly facing surfaces  150  of wings  152 ,  154 , base  156 , and pylons  158 . In some embodiments, talar resection guide  166  can simply slide into guide receptacle recess  146  without operative contact or only incidental engagement with the inwardly facing surfaces  150  of wings  152 ,  154 , base  156 , and pylons  158 . 
     Tibial drill guide mount  200  illustrated in  FIGS. 16-20  also may be fabricated from a resilient polymer material of the type that is suitable for use in connection with stereo lithography, selective laser sintering, or the like manufacturing equipment, e.g., a polyamide powder repaid prototype material is suitable for use in connection with selective laser sintering. As shown in  FIGS. 16-20 , tibial drill guide mount  200  includes a somewhat rectangular body  204  that defines an aperture  206  that extends from a top surface  208  of body  204  to a bottom surface  210  of body  204 . Top surface  208  of body  204  may include a pair of chamfers  212  that are sized and configured to be mate against the resected surfaces of the lower tibia  16   a  ( FIG. 8 ). Put another way, the top or upper surface  208  of body  204 , including chamfers  212 , is complementary to the geometry and locations of slots  138  and  140  of tibial resection guide  132 . 
     Front side  214  of body  204  defines one or more blind holes  216 . As illustrated in the embodiment shown in  FIG. 17 , body  204  may define three blind holes  216 - 1 ,  216 - 2 , and  216 - 3 . In some embodiments, blind holes  216 - 1  and  216 - 2  may be reamed holes that are sized and configured to receive a dowel pin, and blind hole  216 - 3  may also be a reamed hole for receiving a dowel pin or blind hole  216 - 3  may be threaded for engaging a screw as described below. 
     Aperture  206  may have a circular cross sectional area and include a shoulder  218  having a reduced diameter compared to aperture  206  and includes an anti-rotational feature  220  as best seen in  FIG. 20 . Anti-rotational feature  220  of shoulder  218  may include one or more flats or other geometric structure(s) to prevent tibial drill guide  202  from rotating with respect to tibial drill guide mount  200  when tibial drill guide  202  is disposed within aperture  206 . 
     Extending from body  204  of tibial drill guide mount  200  are tibial engagement structure  222  and talar engagement structure  224 . The outer surface  226  of tibial engagement structure  222  may have a rectangular shape that is substantially planar, and the internal and substantially conformal engagement surface  228  of tibial engagement structure  222  may be somewhat convex for engaging the tibia  16  of the patient. Tibial engagement structure  222  may define one or more holes  230  for receiving a k-wire or pin as described below. 
     Talar engagement structure  224  may also include a substantially planar and rectangular outer surface  232 . The lower portion  234  of talar engagement structure  224  may be a conformal surface having a geometry that matches the geometry of the talar bone  14  ( FIG. 14 ). Talar engagement structure  224  may also define one or more holes  236  sized and configured to receive a k-wire as described below. 
     Tibial drill guide  202  illustrated in  FIGS. 21-23  is preferably fabricated from a material having more structural integrity than tibial drill guide mount  200  to enable drill guide  202  to guide a drill bit without being damaged. Examples of materials include, but are not limited to, metals, ceramics, or the like. Drill guide  202  has a cylindrically shaped first portion  238  that is sized and configured to be received within the portion of aperture  206  that extends through the shoulder or reduced diameter area  218 . A second portion  240  of drill guide  202  has a larger cross-sectional diameter than first portion  238  and is sized and configured to be received within aperture  206  of tibial drill guide mount  200 . A flat  242 , which is best seen in  FIGS. 21 and 23 , is formed along an exterior surface  244  of first portion  238  of drill guide  202 . The internal surface  248  of second portion  240  of tibial drill guide  202  has a conical shape that intersects and communicates with aperture  246  such that a drill or reamer may be received through drill guide  202 . 
     As with the digital image models  50  disclosed above, and considering a generalized digital model of a tibial resection guide mount  100  added to the patient&#39;s lower tibia image data, the anatomic surface features of the patient&#39;s lower tibia, e.g., the surface topography, may be complementarily mapped onto each of conformal bone engaging surfaces  116  of arms  110 ,  112 , and central post  114 , i.e., the surfaces that will engage the bones unique surface topography, of tibial resection guide mount  100 . It will be understood that complementary mapping of the digital images results in localized prominences on the surface of a bone becoming localized concavities on conformal bone engaging surfaces  116  of arms  110 ,  112 , and central post  114  of tibial resection guide mount  100 , while localized concavities on the surface of a bone become localized prominences on conformal bone engaging surfaces  116  of arms  110 ,  112 , and central post  114 . 
     Each of conformal bone engaging surfaces  116  of arms  110 ,  112 , and central post  114  of resection guide mount  100  is redefined with a complementary, substantially mirror image of the anatomic surface features of a selected region of the patient&#39;s lower tibia  16   a.  As a consequence of this complementary bone surface mapping, tibial resection guide mount  100  releasably “locks” on to the complementary topography of the corresponding portion of the patient&#39;s natural tibia without the need for other external or internal guidance fixtures. In other words, the mating of bone surface asperities in their corresponding concavities formed in conformal bone engaging surfaces  116  of tibial resection guide mount  100  ensures that little or no relative movement, e.g., slipping sideways, occurs between tibial resection guide mount  100  and the tibial surface. 
     A substantially identical mapping is carried out in connection with the design of a patient specific talar resection guide mount  102  and tibial drill guide mount  200 . Notably, the mapping for the design of tibial drill guide mount  200  is performed by extrapolating where the resections to the tibia  16  and talus  14  will be made using tibial and talar resection guide mounts  100  and  102  and mapping the tibial drill guide mount  200  onto the extrapolated geometry of the tibia and talus. 
     A visual presentation of the virtual alignment results between the patient&#39;s lower tibia  16   a  and resection guide mount  100 , the patient&#39;s upper talus  14   a  and resection guide mount  102 , and the proposed resected area that that is to be created by resecting the talus  14  and tibia utilizing the tibial resection guide mount  100  and the talar resection guide mount  102  are created and forwarded to the surgeon to obtain approval of the results prior to manufacturing. Additionally, the surgeon may be provided with a visual representation of the virtual alignment results between the proposed resected joint space and tibial drill guide mount  200  are created and forwarded to the surgeon to obtain approval of the results prior to manufacturing. Upon receipt of the surgeon&#39;s approval, resection guide mount  100 , resection guide mount  102 , and tibial drill guide mount  200  are manufactured and returned to the surgeon for use in the surgery. 
     During a total ankle replacement, for example, the surgeon makes an anterior incision to gain initial access to the ankle joint. The surgeon orients tibia resection guide mount  100  on lower tibia  16   a  until the conformal bone engaging surfaces  116  of arms  110 ,  112  and central post  114  of tibial resection guide mount  100  securely engage one another so as to releasably “interlock” with the topography of the exposed surface of lower tibia  16   a  as best seen in  FIGS. 5-7 . With tibial resection guide mount  100  locked onto the patient&#39;s lower tibia  16   a,  a surgeon press-fits an appropriately configured distal resection guide  132  in guide receptacle recess  108  of tibial resection guide mount  100 . This results in the resection guide mount  100  being sandwiched between the resection guide  132  and the patient&#39;s bone tibia  16   a  ( FIGS. 5 and 6 ). With the resection guide mount  100  accurately positioned with respect to the selected bone region and resection guide mount  100  construct appropriately secured to the patient&#39;s bone by virtue of the mating of bone surface asperities in their corresponding concavities formed in conformal bone engaging surfaces  116 , the surgeon uses a conventional surgical blade  60  and the resection slots  128  and  130  of resection guide  132  to resect the patient&#39;s bone  16  ( FIGS. 7 and 8 ). 
     In a similar fashion, when talar resection guide mount  102  is added to the patient&#39;s talar image data, the anatomic surface features of the patient&#39;s upper talus, e.g., the surface topography, may be complementarily mapped onto conformal bone engaging surface  144 . It will again be understood that complementary mapping of the digital images results in localized prominences on the surface of a bone becoming localized concavities on conformal bone engaging surface  144 , while localized concavities on the surface of a bone become localized prominences on conformal bone engaging surface  144 . In this way, conformal bone engaging surface  144  is redefined with a complementary, substantially mirror image of the anatomic surface features of a selected region of the patient&#39;s lower tibia. As a consequence of this complementary bone surface mapping, talar resection guide mount  102  releasably “locks” on to the complementary topography of the corresponding portion of the patient&#39;s natural talus without the need for other external or internal guidance fixtures. 
     To continue the total ankle replacement the surgeon orients resection guide mount  102  on upper talus  14   a  until conformal bone engaging surface  144  of resection guide mount  102  “locks” to the topography of the exposed surface of upper talus  14   a  ( FIG. 11 ). With resection guide mount  102  locked onto the patient&#39;s upper talus, a surgeon press-fits an appropriately configured distal resection guide  166  in guide receptacle recess  146  of talar resection guide mount  102 . This results in resection guide mount  102  being sandwiched between resection guide  166  and the patient&#39;s bone  14  ( FIGS. 12 and 13 ). With the resection guide mount  102  accurately positioned with respect to the selected bone region and resection guide  166  and guide mount  102  appropriately constructed and secured to the patient&#39;s bone, by virtue of the mating of bone surface asperities in their corresponding concavities formed in conformal bone engaging surfaces  144 , the surgeon uses a conventional surgical blade  60  and the resection slot  164  of resection guide  166  to resect the patient&#39;s bone  14  ( FIGS. 13 and 14 ). 
     Once the tibia  16  and talus  14  have been resected, tibial drill guide mount  200  and tibial drill guide  202  are coupled together and installed into resected joint space  22  ( FIG. 15 ). Tibial drill guide mount  200  and tibial drill guide  202  are coupled together by inserting first portion  238  of tibial drill guide  202  into aperture  206  defined by body  204  of tibial drill guide mount  200  ( FIG. 24 ). Flat  242  formed on the first portion  238  of tibial drill guide  202  is aligned with anti-rotation feature  220  of shoulder  218  such that tibial drill guide  202  slides into aperture  206  until a lower surface  250  of second portion  240  of drill guide  202  contacts and abuts shoulder  218  of tibial drill guide mount  200 . 
     Body  204  of tibial drill guide mount  200 , in which tibial drill guide  202  is disposed, is inserted into resected joint space  22  in an anterior posterior direction with chamfers  212  sliding along resected areas of tibia  16  formed by utilizing slots  140  of tibial resection guide  132  as best seen in  FIGS. 25A and 25B . The assemblage of tibial drill guide mount  200  and tibial drill guide  202  are slid into resected joint space  22  until talar engagement structure contacts talus  14 . A surgeon may move tibial guide mount  200  within resected joint space until conformal surface  228  is appropriately secured to the patient&#39;s bone by virtue of the mating of bone surface asperities in their corresponding concavities formed in conformal bone engaging surface  228 . Once properly located, k-wires  62  may be inserted into holes  230  and/or holes  236 , respectively defined by tibial engagement structure  222  and talar engagement structure  224 , to secure the assemblage of the tibial drill guide mount  200  and tibial drill guide  202  to the patient&#39;s tibia  16  and talus  14  as illustrated in  FIG. 25C . 
     With tibial drill guide mount  200  and tibial drill guide  202  secured within resected joint space  22 , the patient&#39;s leg is inserted into a foot holder and alignment tool  300 .  FIGS. 26-28B  illustrate one example of an alignment tool  300 , which serves the task of supporting the ankle joint during a prosthesis installation procedure. Alignment tool  300  includes a foot holder assembly  302  and a leg rest  304 . Foot holder assembly  302  includes a foot rest  306 , to which the foot is secured by a foot clamp  310  and heel clamps  308  during an prosthesis installation procedure. The calf of the leg is suitably secured to the leg rest  304  once the ankle joint has been resected and tibial drill guide mount  200  and tibial drill guide  200  have been installed. Together, foot holder assembly  302  and leg rest  304  hold the foot and ankle relative to the leg during an installation procedure. 
     As shown in  FIG. 26 , foot holder assembly  302  is sized and configured for pivoting, under control of the physician, from a vertical or upright condition (shown in solid lines in  FIG. 26 ) toward a more horizontal or tilted condition (shown in phantom lines in  FIG. 26 ). In the upright condition, assembly  302  serves to hold the ankle joint in a desired orientation with respect to the natural anterior-to-posterior and medial-to-lateral axes. 
     As best seen in  FIG. 27 , foot holder assembly  302  includes a back plate  312  and a mid-plate  314 , which is sandwiched between foot rest  306  and back plate  312 . Mid-plate  314  is coupled to the foot rest  306  by sliding dovetail couplings  316  for up-and-down (i.e., vertical) movement relative to foot rest  306 . A pair of oppositely spaced alignment rods  318  is carried by the mid-plate  314 . 
     Alignment rods  318  are disposed in the same horizontal plane and extend from mid-plate  314  through vertically elongated slots  320  defined by foot rest  306  such that rods  318  are disposed on opposite sides of the tibia in the medial-to-lateral plane when a foot is supported by foot holder assembly  302 . Vertical movement of mid-plate  314  moves alignment rods  318  up-and-down in unison within slots  320  on opposite sides of the foot rest  306  ( FIG. 28A ). 
     Back plate  312  is coupled to mid-plate  314  by sliding dovetail couplings  322  for side-to-side (i.e., horizontal) movement relative to foot rest  306  as illustrated in  FIG. 28B . Back plate  312  also carries a bushing  324 , which extends through openings  326  defined by mid-plate  314  and foot rest  306  and terminates at or near the plane of the foot rest  306  against which the bottom of the foot contacts. The center of the bushing  324  coincides with the intersection of the horizontal plane of the rods  318 . 
     An adapter bar  400  for coupling tibial drill guide mount  200  to alignment tool  300  is illustrated in  FIG. 29 . Adapter bar  400  includes an elongate body  402  linearly extending from a first end  404  to a second end  406 . Each of the ends  404 ,  406  includes a respective extension  408 ,  410  that extends from elongate body  402  at an angle. In some embodiments, extensions  408  and  410  orthogonally extend from elongate body  402 , although one skilled in the art will understand that extensions  408  and  410  may diverge from elongate body  402  at other angles. In some embodiments, elongate body  402  may not have a linear shape, but may have a curved or arced shape as will be understood by one skilled in the art. 
     Each extension  408  and  410  defines a respective hole  412 ,  414  that is sized and configured to slidably receive alignment rods  318  that extend from alignment tool  300 . Elongate body  402  defines one or more holes  416 - 1 ,  416 - 2 , and  416 - 3  (collectively referred to as “holes  416 ”) for coupling to adapter bar  400  to tibial drill guide mount  200 . In some embodiments, the one or more holes  416  align with one or more holes  216  defined by body  204  of tibial drill guide mount  200  such that a pin or other device for maintaining the alignment and engagement of adapter bar  400  and tibial drill guide mount  200 . For example, holes  216 - 1  and  216 - 2  of tibial drill guide mount  200  align with holes  416 - 1  and  416 - 2  of adapter bar  400 , and hole  216 - 3  of drill guide mount  200  aligns with hole  416 - 3  of adapter bar  400 . Dowel pins  70  (shown in  FIG. 25C ) may be inserted into holes  216 - 1  and  416 - 1  as well as into holes  216 - 2  and  416 - 2  to align tibial drill guide mount  200  with adapter bar  400  in both the horizontal and vertical directions (e.g., in the x- and y-directions), and a screw (not shown) may be inserted through hole  416 - 3  into threaded hole  216 - 3  to secure tibial drill guide mount  200  to adapter bar at the proper height or depth (e.g., in the z-direction). 
     With tibial drill guide mount  200  and tibial drill guide  202  disposed within the resected ankle space  22 , the foot and lower leg are placed in foot rest  306  and leg rest  304  ( FIG. 30 ). The physician estimates the ankle&#39;s axis of dorsi-plantar rotation and visually aligns the ankle to the axis of rotation of the alignment tool  300 . Foot rest  306  is adjusted to rotate the foot so that the big toe is essentially pointing in a vertical direction with respect to the leg that extends in a horizontal direction. The forefoot and heel are secured to foot rest  306  with clamps  308  and  310 . Leg rest  304  is adjusted to the calf so that the tibia  16  is approximately parallel to the floor. The foot and calf are desirably aligned so that the anterior-posterior (“A-P”) line of the talus&#39;s trochlea is essentially vertical. 
     Adapter bar  400  is coupled to alignment tool  300  by aligning holes  412  and  414  that are respectively defined by extensions  408  and  410  with alignment rods  318  of alignment tool  300 . Adapter bar  400  is then slid along alignment rods  318  until holes  416  of adapter bar align with holes  216  defined by body  204  of tibial drill guide  200  ( FIG. 30 ). As described above, dowel pins  70  are inserted into holes  416 - 1  and  416 - 2  of adapter bar  400  and holes  216 - 1  and  216 - 2  of tibial drill guide mount  200 . With dowels  70  disposed within holes  216 - 1 ,  216 - 2 ,  416 - 1 , and  416 - 2 , tibial drill guide mount  200  is properly aligned with alignment tool  300  in the medial lateral (e.g., x-direction) and superior-inferior (e.g., y-direction) directions. A screw is inserted through hole  416 - 3  into threaded hole  216 - 3 , which secures tibial drill guide mount  200  to adapter bar  400  and provides proper alignment in the anterior-posterior direction (e.g., the z-direction). 
     With the patient&#39;s foot disposed within alignment tool  300 , bushing  324  on back plate  312  establishes alignment with the mechanical axis of tibia  16  and alignment of rods  318 . Thus, after using adapter bar  400  to align tibial drill guide mount  200  with alignment tool  300  as described above, in line drilling of the center of the ankle and tibia for introduction of a bottom foot cannula is made possible without the use of fluoroscopy since aperture  246  of tibial drill guide  202  disposed within tibial drill guide mount  200  is aligned with an axis defined by bushing  324 . Such arrangement enables an intramedullary channel to be formed that is substantially collinear with a mechanical axis defined by the tibia. 
     Various minimally invasive surgical techniques may be used to introduce a bottom foot cannula into the calcaneus  20 , talus  14 , and tibia  16 . In one representative embodiment, bushing  324  is temporarily separated from the back plate  312  (e.g., by unscrewing) to provide access to the bottom of the foot. The physician uses a scalpel to make an initial incision in the bottom of the foot and replaces bushing  324 . A cannulated trocar loaded with a k-wire (not shown) can be inserted through bushing  324 , into the bottom of the foot, until the calcaneus  20  is contacted and the k-wire is firmly set within the calcaneus  20 . The trocar can then be removed, and the k-wire lightly tapped further into the calcaneus  20 . In a representative embodiment, the bushing  324  measures 6 mm in diameter, and the cannulated trocar can be 6 mm loaded with a 2.4 mm k-wire. The physician can now operate a cannulated first reamer (e.g., 6 mm) (not shown) over the k-wire up into the calcaneus  20  and talus  14 . The first reamer opens an access path for insertion of a bottom foot cannula. 
     After withdrawing the first reamer and bushing  324 , the physician then inserts a bottom foot cannula  64  as shown in  FIG. 30 . With the bottom foot cannula  64  in place, a second reamer  66  (e.g., 5 mm) can be operated through the cannula  64  to drill approximately another 100 mm through the talus  14  and up into the tibia  16  to establish an intramedullary guide path through the calcaneus  20  and talus  14  leading into the tibia  16  ( FIG. 30 ). As second reamer  66  is advanced towards tibia  16 , the tip  68  of reamer  66  is guided by the conical interior surface  248  of tibial drill guide  204 , which is aligned with bushing  324  of alignment tool  300 . 
     Once an intramedullary channel through the calcaneus  20 , talus  14 , and tibia  16  has been established, adapter bar  400  is decoupled from drill guide mount  200  and alignment rods  318 . Drill guide mount  200  is removed from resected joint space  22  to expose the resected joint space to the surgeon. 
     With the resected ankle joint space  22  exposed to the surgeon, an ankle prosthesis is then installed. In one example, the ankle prosthesis includes a stem that may extend from the bottom of the calcaneus up to the top of the talus (i.e., a talo-calcaneal stem), although in some embodiment the stem is completely disposed within the talus (i.e., a talar stem). A convex dome is coupled to the stem and provides an articulating joint surface. A tibial stem may be monolithic or include a plurality of segments that may be coupled together in situ. A tibial platform couples to the tibial stem and either includes or is coupled to a convex joint surface for articulating with the articulating joint surface coupled to the talar/talo-calcaneal stem. Examples of such ankle prosthesis and methods of installing such prosthesis are disclosed in U.S. Pat. No. 7,534,246 issued to Reiley et al., the entirety of which is herein incorporated by reference. 
     The disclosed tibial drill guide mount  200  and drill guide  202  may be used with a variety of alternative alignment tools. For example,  FIGS. 31-34  illustrate another example of an alignment tool in the form of a foot holder assembly  500  to which tibial drill guide mount  200  may be directly coupled. As shown in  FIGS. 31 and 32 , foot holder assembly  500  includes a base plate  502  defining a plurality of slots  504  and  506  and an aperture  503 . 
     Slots  504  are sized and configured to slidably receive a pair of heel clamps  508 , and slots  506  are sized and configured to slidably receive a pair of forefoot clamps or guides  510 . Heel clamps  508  and forefoot clamps  510  cooperate to maintain a foot of a patient in a desired position with respect to base plate  502  by utilizing a locking mechanism such as, for example, a set screw or other locking device, to fix the position of heel clamps  508  and forefoot clamps  510  to base plate  502 . The respective foot engaging surfaces  512  and  514  of heel clamps  508  and forefoot clamps  510  may have a shape that complements the medial and lateral shape of a human foot. 
     Extending from base plate  502  are a pair of alignment rods  516  that are arranged on base plate  502  such that one alignment rod is disposed on a medial side of a patient&#39;s foot and the other alignment rod is disposed on a lateral side of a patient&#39;s foot. A coupling bar  518  is sized and configured to slidably engage alignment rods  516  as best seen in  FIGS. 32 and 34 . Coupling bar  518  includes a pair of spaced apart legs  520  that define channels  522  ( FIG. 32 ) in which alignment rods  516  are slidably received. One or both of legs  520  include a clamp or other locking mechanism  524  for increasing the friction between coupling bar  518  and alignment rods  516  in order to releasably lock coupling bar  518  at a certain position along the length of alignment rods  516 . 
     Medial-lateral cross bar  526  couples together legs  520  of coupling bar  518 . Extending from medial-lateral cross bar  526  is mount coupling member  528 . Mount coupling member  528  includes one or more holes  530 - 1 ,  530 - 2 , and  530 - 3  (collectively referred to as “holes  530 ”) that are sized and configured to align with holes  216  defined by tibial drill guide mount  200 . 
     A peg  532  ( FIG. 33 ) extends from medial-lateral cross bar  526  for coupling shin engaging member  534  via slot  536  defined by shin engaging member  534 . Shin engaging member  534  includes a shelf  538  having a concave surface  540  for abutting a shin of a patient. A nut or other locking mechanism (not shown) for engaging peg  532 , which may be threaded, may be used to fix the position of shelf  538  relative to medial-lateral cross bar  526 . 
     The use of foot holder assembly  500  in connection with the assemblage of tibial drill guide mount  200  and tibial drill guide  202  is similar to the use of alignment tool  300  described above. For example, once the assembly of tibial drill guide mount  200  and tibial drill guide  202  are disposed within resected joint space  22 , the heel of the patient&#39;s foot is placed between heel clamps  508  and the patient&#39;s forefoot is placed between forefoot clamps  510 . The locking mechanisms of heel and forefoot clamps  508  and  510  may be engaged to initially set positions of heel and forefoot clamps  508  and  510  relative to base plate  502 . 
     Holes  530  of coupling member  528  are aligned with holes  216  defined by tibial drill guide mount  200  by sliding legs  520  of coupling bar  518  along alignment rods  516 . Dowel pins  70  and/or a threaded screw (not shown) may be used to couple holes  530  of coupling member  528  to holes  216  of tibial drill guide mount  200 . The surgeon may check to ensure that the patient&#39;s foot is firmly against base plate  502  and then engage clamps  524  such that coupling bar  518  is fixed to alignment rods  516 . 
     Shin engaging member  534  is adjusted until concave surface  540  contacts the patient&#39;s shin. The adjustment of shin engaging member  534  is guided by the engagement between slot  536  and peg  532 . With shin engaging member  534  in the desired position, the nut or other locking mechanism (not shown) locks shin engagement member  534  in place. The surgeon may make final adjustments to the heel and forefoot clamps  508  and  510  and then create the intramedullary channel as described above. 
     Another example of an alignment tool  600  for use with tibial drill guide mount  200  and tibial drill guide  202  is illustrated in  FIGS. 35-38 . As shown in  FIG. 35 , alignment tool  600  includes a base plate  602  comprising a plurality of bars  602   a,    602   b,  and  602   c.  Although three bars  602   a,    602   b,  and  602   c  are illustrated, one skilled in the art will understand that fewer or more bars may be implemented. Bar  602   b  defines a hole  603  sized and configured to receive a surgical tool, such as, for example, a cannulated drill. Additional elements including, but not limited to, heel clamps and/or forefoot clamps (not shown) may be coupled to the bars  602   a ,  602   b,  and  602   c  of base plate  602  for aiding in the positioning of a patient&#39;s foot with respect to hole  603 . 
     Extending from base plate  602  is a pair of spaced apart alignment rods  604 . One of alignment rods  604  may be disposed on a medial side of a patient&#39;s leg, and the other alignment rod  604  disposed on a lateral side of the patient&#39;s leg. Alignment rods  604 , like alignment rods  318  of alignment tool  300 , may be slidably receiving within holes  412 ,  414  of adapter bar  400 . 
     The use of alignment tool  600  in connection with the assemblage of tibial drill guide mount  200  and tibial drill guide  202  and the adapter bar  400  is similar to the use of alignment tool  300  described above. For example, once the assembly of tibial drill guide mount  200  and tibial drill guide  202  are disposed within resected joint space  22 , adapter bar  400  is coupled to alignment tool  600  by aligning holes  412  and  414  that are respectively defined by extensions  408  and  410  with alignment rods  604  of alignment tool  600 . Adapter bar  400  is slid along alignment rods  604  until holes  416  of adapter bar align with holes  216  defined by body  204  of tibial drill guide  200 . As described above, dowel pins are inserted into holes  416 - 1  and  416 - 2  of adapter bar  400  and  216 - 1  and  216 - 2  of tibial drill guide mount  200 . With dowels disposed within holes  216 - 1 ,  216 - 2 ,  416 - 1 , and  416 - 2 , tibial drill guide mount  200  is properly aligned with alignment tool  600  in the medial lateral (e.g., x-direction) and superior-inferior (e.g., y-direction) directions. A screw is inserted through hole  416 - 3  into threaded hole  216 - 3 , which secures tibial drill guide mount  200  to adapter bar  400  and provides proper alignment in the anterior-posterior direction (e.g., the z-direction). The surgeon may make final adjustments to the heel and forefoot clamps  508  and  510  and then create the intramedullary channel as described above. 
       FIGS. 39-63  illustrate another embodiment of a system for performing a surgical procedure. Specifically,  FIGS. 39-43  illustrate a tibial drill guide mount  700  sized and configured to receive the tibial drill guide cartridge  702  illustrated in  FIGS. 44-47 . Tibial drill guide mount  700  may also receive other drill guide cartridges for use during other stages of the surgical procedures. Like tibial drill guide mount  200 , tibial drill guide  700  may be fabricated from a resilient polymer material of the type that is suitable for use in connection with stereo lithography, selective laser sintering, or the like manufacturing equipment, e.g., a polyamide powder repaid prototype material is suitable for use in connection with selective laser sintering. 
     As shown in  FIG. 39-43 , tibial drill guide mount  700  has a somewhat rectangular body  704  having a front side  706 , a rear side  708 , top side  710 , bottom side  712 , and a pair of opposed sides  714  and  716 . Front side  706  defines a recess  718  sized and configured to slidably receive tibial drill guide  702  therein. Recess  718  communicates with a recess  720  ( FIGS. 39 and 43 ) defined by bottom side  712  and a recess  722  ( FIGS. 39, 42, and 43 ) defined by top side  710  such that body  704  is substantially hollow. 
     The respective inner surfaces  724 ,  726  of sides  714 ,  716  have different geometries that correspond with the cross-sectional geometry of tibial drill guide cartridge  702  to ensure that tibial drill guide cartridge  702  is properly inserted into recess  718 . In the embodiment illustrated in  FIGS. 39-43 , side  716  includes first and second ledges  728 ,  730  that inwardly extend into recess  718 , and side  714  has an inwardly tapered upper region  732  and an inwardly extending ledge  734 . One skilled in the art will understand that sides  714 ,  716  may include other features for ensuring proper insertion of tibial drill cartridge  702  into recess  718 . In some embodiments, sides  714 ,  716  may have the identical geometry and tibial drill guide cartridge may be reversibly inserted into recess  718 . 
     Front side  706  defines one or more dowel holes  736 - 1 ,  736 - 2  (collectively referred to as “dowel holes  736 ”) sized and configured to receive a dowel pin  70  therein. One or more through holes  738 - 1 ,  738 - 2 ,  738 - 3  (collectively referred to as “through holes  738 ”) extend through front side  706 , which also defines a blind hole  740 . Through holes  738  are sized and configured to receive k-wires for pinning tibial drill guide mount to a patient&#39;s bone as described below. 
     Top side  710  of tibial drill guide mount  700  includes a pair of chamfers  742  that are sized and configured to be mate against and reference the resected surfaces of the lower tibia  16   a  ( FIG. 8 ). Tibial drill guide mount  700  also includes a tibial engagement structure  744  and a talar engagement structure  746 . Tibial engagement structure  744  extends from top side  710  and includes a substantially conformal engagement surface  748 . Talar engagement structure  746  extends from bottom side  712  and also includes a substantially conformal engagement surface  750 . 
     Tibial drill guide cartridge  702  has a substantially rectangular elongate body  754  that may be formed from a more substantial material than tibial drill guide mount  700  such as, for example, metals, ceramics, or the like. As best seen in  FIGS. 44 and 45 , the geometry of sides  756 ,  758  is respectively complementary to the sides  714 ,  716  of tibial drill guide mount  700 . For example, side  758  includes ledges  760  and  762  that respectively correspond to ledges  728  and  730 , and side  756  includes a ledge  764  and an angled section  766 , which respectively correspond to ledge  734  and upper region  732  of tibial drill guide mount  700 . 
     Front side  768  of tibial drill guide cartridge  700  defines a blind hole  770 , which may be threaded for reasons described below. Tibial drill guide cartridge  702  defines a pair of holes  772  and  774  that extend from bottom surface  776  to top surface  778 . Hole  772  may be a reamed hole that is sized and configured to receive a ball detent therein, and hole  774  has an internal surface  780  that tapers from a larger diameter at bottom surface  776  to a smaller surface that is sized and configured to receive a surgical tool, such as a drill and/or reamer. Top surface  778  defines a pair of parallel slots  782 - 1 ,  782 - 2  (collectively referred to as “slots  782 ”) that extend from side  756  to side  758 . As best seen in  FIGS. 44 and 47 , slots  782  are disposed equidistant from a central axis defined by hole  774  to provide a visual key for a physician that wants check the alignment of hole  774  with a mechanical axis of a patient&#39;s tibia using fluoroscopy. 
     As illustrated in  FIGS. 48 , a mounting plate  800  has a substantially rectangular body  802  that is fabricated from a material including, but not limited to, metals, ceramics, or the like. Body  802  defines an aperture  804  the extends from front side  806  to back side  808  and has a similar geometry of recess  718  of tibial drill guide mount  700  such that tibial drill guide cartridge  702  may be received therein. Body  802  also defines a pair of through holes  810 - 1 ,  810 - 2  (collectively referred to as “holes  810 ”) that are arranged on body  802  such that they correspond to holes  738  of tibial drill guide mount  700  and are sized and configured to receive a k-wire or pin therein. 
     A mounting base  812  extends from front side  806  of mounting plate  800  and defines a hole  814  that extends from a first side  816  to a second side  818 . Mounting base  812  defines a notch  820  and one or more dowel pin holes  822 - 1 ,  822 - 2  (collectively referred to as “holes  822 ”) that are aligned with holes  736  of tibial drill guide mount  700 . Notch  820  bisects hole  814 . Mounting base  812  may also define one or more recesses  824  that correspond to one or more protrusions  784  that extends from front side  706  of tibial drill guide mount  700 . Recesses  824  and protrusions  784  cooperate to ensure that mounting base  812  and tibial drill guide mount  700  are properly aligned. One skilled in the art will understand that other geometric features may be implemented to ensure proper alignment between mounting base  812  and tibial drill guide mount  700 . 
     As illustrated in  FIGS. 49-54 , mounting plate  800  may be coupled to tibial drill guide mount  700  using dowel pins  70 , which are received through holes  822  and  734 . Tibial drill guide cartridge  702  is received through aperture  804  and recess  718  as best seen in  FIG. 51 .  FIGS. 53 and 54  illustrate that when tibial drill guide cartridge  702  is properly inserted into the assemblage of tibial drill guide mount  700  and mounting plate  800 , hole  772  aligns with hole  828  defined by mounting plate  800 , which may include a ball detent (not shown) disposed therein. Consequently, the ball detent is received within hole  772  to retain tibial drill guide cartridge  702  disposed within aperture  804  and recess  718  such that hole  774  is disposed within recesses  754  and  756 . A screw or other threaded object (not shown) can be inserted into threaded hole  770  and then pulled to remove tibial drill guide cartridge  702  from aperture  804  and recess  718  as illustrated in  FIGS. 53 and 54 . 
     Tibial drill guide mount  700 , tibial drill guide  702 , and mounting plate  800  may be used in connection with alignment tool  300 , adapter bar  400 , foot holder assembly  500 , and alignment tool  600  as described above. Additionally, tibial drill guide mount  700 , tibial drill guide  702 , and mounting plate  800  may also be used in conjunction with foot holder assembly  900  illustrated in  FIGS. 55-60  as can tibial drill guide mount  200  and tibial drill guide  202 . 
     As shown in  FIG. 55 , foot holder assembly  900  includes a base plate  902  that extends from a first end  904  to a second end  906 . First and second ends  904 ,  906  each define a pocket  908  and a hole  910 . Pocket  908  is sized and configured to receive a drill bushing  912  having a cylindrical body defining hole  914  that aligns with through hole  910 . Accordingly, both first end  904  and second end  906  may support an ankle or forefoot of a patient. Each pocket  908  includes a spring loaded detent  916  communicatively coupled to it that include a finger receiving surface  918  and is configured to slide relative to base plate  902  and secure drill bushing  912  within pocket  908 . In some embodiments, drill bushing may be threaded and configured to be coupled to base plate  902  with complementary threads disposed on an inner surface of holes  910 . 
     Base plate  902  also includes a medial/lateral extension  920  that extends in a substantially perpendicular direction from an approximate mid-point between first end  904  and second end  906 . Base plate  902  may also define a viewing opening  922  such that a surgeon may be able to view the bottom of a patient&#39;s foot when the foot is secured to foot holder assembly  900 . 
     One or more rods  924  extend from base plate  902  in a substantially perpendicular direction with respect to an upper foot holding surface  926  ( FIG. 56 ). Rods  924  may be secured to base plate  902  using screws or through other securing means as will be understood by one skilled in the art. A cap  928  is secured to an upper end of rods  924  and be secured to rods  924  using screws or other fixation means. 
     A mounting member  930  has an elongate body  932  that defines a pair of holes  934 ,  936  at one end  938  that slidably receive rods  924  such that mounting member  930  may be slid along rods  924  in order to position tibial drill guide mount  700  with respect to base plate  902 . A spring loaded button  940  is disposed at first end  938  of mounting member  930  and is coupled to a locking mechanism (not shown) disposed within mounting member  930  for locking mounting member  930  at a position along rods  924 . 
     One or more holes  942  are defined at the second end  944  of mounting member  930  and correspond to holes  716  of drill guide mount  700  for coupling drill guide mount  700  to foot holder assembly  900 . Second end  942  also defines a slot  946 , as best seen in  FIGS. 56 and 60 , that is sized and configured to receive an internally threaded rod  948  of a pivoting arrangement  950 , which includes a lower portion  952  that is received within slot  820  of mounting plate  800  and is cross-pinned through hole  814 . The cross-pinning of pivoting arrangement  950  may pivot about an axis defined by hole  814  and is configured to receive an support tightening knob  954 . Bottom surface  956  ( FIG. 60 ) of knob  954  has an outer dimension that is greater than slot  946  and is configured to engage mounting member  930  in order to secure the assemblage of mounting plate  800  and tibial drill guide mount  700 , which may include tibial drill cartridge  702 . 
     In operation, tibial drill guide mount  700  is inserted into resected joint space  22 . Mounting plate  800  is connected to tibial drill guide mount  700  using dowel pins  70  as best seen in  FIGS. 49 and 50 . With pivoting arrangement  950  cross-pinned to mounting plate  800 , the assemblage of mounting plate  800  and pivoting arrangement  948  is coupled to tibial drill guide mount with dowel pins  70 , which may be press fit into holes  822  of mounting plate  800  and holes  716  of tibial drill guide mount  700  as will be understood by one skilled in the art. Tibial drill guide mount  700  and mounting plate may be secured within resected joint space  22  by inserting k-wires (not shown) into holes  736 ,  790  defined by tibial drill guide mount  700  and holes  830 - 1 ,  830 - 2  (corresponding to holes  736 - 1 ,  736 - 2 ) and  832 - 1 ,  832 - 2  defined by mounting plate  800 . 
     With mounting plate  800  coupled to tibial drill guide mount  700  that is disposed within resected joint space  22 , pivoting arrangement  948  is rotated such that it extends in a direction approximately parallel to a longitudinal axis defined by a patient&#39;s leg and the cartridge-style tibial drill guide  702  is inserted into aperture  804  of mounting plate  800  and recess  718  of tibial drill guide mount  700 . Tibial drill guide cartridge  702  is inserted until leading end  786  of tibial drill cartridge  702  abuts rear wall  788  of tibial drill guide mount  700  at which point the ball detent disposed within hole  772  engages hole  828  defined by mounting plate  800  and the front side  768  of tibial drill guide cartridge  702  is flush with front side  806  of mounting plate  800 . 
     Holes  940  of mounting member  930  are aligned with, and received over, dowel pins  70  that extend from front side  806  of mounting plate to couple mounting member  930  of foot holder assembly  900  to the assemblage of mounting plate  800 , tibial drill guide mount  700 , and tibial drill guide cartridge  702 . With mounting member  903  coupled to dowel pins  70  and mounting plate  800 , pivoting arrangement  948  is rotated with respect to mounting plate  800  such that rod  946  of pivoting arrangement  948  is received within slot  944  of mounting member  930 . Knob  952  is then rotated about its axis (clockwise or counterclockwise) such that the bottom surface  954  of knob  952  contacts mounting member  930  to maintain engagement between mounting member  930  and the assemblage of tibial drill guide mount  700  and mounting plate  800 . 
     Drill bushing  912  is coupled to hole  910  that is aligned with the heel of a patient&#39;s foot. As described above, drill bushing  912  may be slid into pocket  908  defined by bottom plate  902  until spring loaded detents  916  releasably lock drill bushing  912  in place. In some embodiments, drill bushing  912  may be screwed into base plate  902  by way of corresponding threads disposed on an outer surface of drill bushing  912  that engage threads defined by an inner surface of pocket  908  and/or hole  910 . With drill bushing  912  in place and the patient&#39;s leg secured to foot holder assembly  900 , various minimally invasive surgical techniques may be used to introduce a bottom foot cannula into the calcaneus  20 , talus  14 , and tibia  16  as described above. 
     Once access to the patent&#39;s calcaneus has been achieved, a bottom foot cannula  64  is inserted through the patient&#39;s calcaneus  20 . A reamer  66  is operated through the cannula  64  to drill approximately another through the talus  14  and up into the tibia  16  to establish an intramedullary guide path through the calcaneus  20  and talus  14  leading into the tibia  16 . As reamer  66  exits talus  14 , the conically shaped internal surface  748  guides the tip  68  into hole  788 . An axis defined by hole  788  is substantially axially aligned with a mechanical axis of tibia  16  such that as reamer  66  is extended through hole  788 , it bores an intramedullary canal within tibia  16 . 
     The disclosed system and method advantageously utilize custom manufactured surgical instruments, guides, and/or fixtures that are based upon a patient&#39;s anatomy to reduce the use of fluoroscopy during a surgical procedure. In some instances, the use of fluoroscopy during a surgical procedure may be eliminated altogether. The custom instruments, guides, and/or fixtures are created by imaging a patient&#39;s anatomy with a computer tomography scanner (“CT”), a magnetic resonance imaging machine (“MRI”), or like medical imaging technology prior to surgery and utilizing these images to create patient-specific instruments, guides, and/or fixtures. 
     Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.