Abstract:
Devices and methods for use in hip replacement surgery can incorporate computer models of a patient&#39;s acetabulum and surrounding bone structure, a first patient-specific jig designed from the computer model and configured to correspond to a final installation position and orientation of a prosthetic him implant, a second patient-specific jig, also designed from the computer model, configured to refine the procedure, if necessary, following use of the first patient-specific jig, and/or a third patient specific jig, designed from the computer model, configured to refine the procedure, if necessary, following use of the first and second patient-specific jigs, allowing the surgeon to properly position and orient the hip prosthesis. Also shown and described are novel devices for implanting an acetabular cup.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to devices and methods for the replacement of joints, and more particularly, to patient-specific hip replacement devices, including methods of manufacturing and using such devices for achieving accurate hip replacement based on computer generated imaging of a patient. 
         [0003]    2. Background of the Invention 
         [0004]    One known method of treating hip and other joints with arthritis and other medical conditions is to replace surfaces of articulating joints with prosthetic devices through surgical procedures. It is critical that such prosthetic devices are accurately designed and manufactured, and are installed correctly in order to relieve pain and provide an effective treatment method for such ailments. An orthopedic surgeon performing such joint replacement on a patient seeks to ensure, through surgery, adequate placement of the prosthetic and proper reconstruction of the joint being replaced. Prosthetic components used to replace a joint may placed optimally by templates and jigs according to the unique anatomy of a patient before surgery occurs. A particular patient&#39;s bone structure symmetry is one important consideration that a surgeon must consider when performing joint replacement surgery. Additionally, malposition of joint replacement prosthetics can result in premature wear of the bearing surfaces, which may require additional surgeries to correct. 
         [0005]    In the case of a hip, the condition of the patient&#39;s joint may require a partial or total replacement. A partial hip replacement involves replacing the femoral head (the ball) of the damaged hip joint; however, the acetabulum (the socket) is not replaced in a partial hip replacement surgery. A total hip replacement includes replacing both the femoral head and the acetabulum with prosthetic devices. The femoral head is replaced with a femoral prosthetic that typically includes a head portion and a stem. The stem extends into the femur of the patient and is utilized to secure the femoral device to the femur, with the head portion protruding out from the femur. The acetabulum is then resurfaced and replaced with a cup-shaped acetabular device. The cup-shaped acetabular device provides a bearing surface for the head portion of the femoral prosthetic to allow a desirable amount of range of motion via the joint upon total hip replacement. 
         [0006]    To replace the acetabulum effectively, a surgeon will typically enlarge the acetabulum with a reamer machine and reamer head to create a resurfaced cavity to receive a prosthetic acetabular cup, which may or may not be secured by cement or bone screws. One particular issue of concern during the reaming portion of the surgery is that the cutting portion of the reamer is hemispherical while the prosthetic acetabular cup is typically sub-hemispherical. If the acetabulum is reamed too deeply, the prosthetic acetabular cup will be positioned too deep within the reamed cavity. If the acetabulum is reamed too shallowly, the prosthetic acetabular cup will not be positioned deep enough. If the acetabulum is reamed at an improper angle, the prosthetic acetabular cup will not be installed properly. These imperfections can cause malalignment of the prosthetic hip joint. Thus, accurate reaming of the acetabulum and accurate positioning of the prosthetic acetabular cup are critical. 
         [0007]    With the assistance of computer generated data derived from CT, MRI, or other scans, surgeons can more effectively determine proper alignment and positioning of the prosthetic acetabular cup in a patient through 3D modeling and rendering. While some surgeons use lasers during surgery in an attempt to properly place the prosthetic acetabular cup; however, accuracy and simplicity of existing devices and methods remain limited due to a variety of factors. 
       BRIEF SUMMARY 
       [0008]    The present disclosure pertains to patient-specific hip replacement devices and methods of designing and manufacturing such devices for achieving accurate acetabular component placement during hip replacement surgery based on computer generated imaging of a particular patient. When an orthopedic surgeon recommends total hip replacement surgery for a particular patient, a variety of images may be obtained utilizing CT, MRI, and other scans to generate 3D modeling of the patient&#39;s bone structure, particularly the femur, the pelvic bone, and the coxal (hip) bone. From such 3D models, the surgeon may determine the specific, final location and orientation of an acetabular cup to be secured to the patient&#39;s acetabulum during surgery. Once the final location and orientation of the acetabular cup is determined, the surgeon (utilizing 3D images) may create a first patient-specific jig and a second—and in some cases a third—patient-specific jig to be inserted into the patient&#39;s acetabulum during the surgery to ultimately achieve accurate positioning of the prosthetics to be installed in the patient. 
         [0009]    The first patient-specific jig may be designed and manufactured based on a first patient-specific acetabulum male portion, while the second patient-specific jig may be designed and manufactured based on a second patient-specific acetabulum male portion. The first and second patient-specific acetabulum male portions can be developed as either physical components via a prototyping machine or visual representations in a 3D modeling software program based upon the 3D images of the patient. The male portion may or may not fully contact the patient&#39;s native acetabulum. 
         [0010]    The first patient-specific jig can be a hemispherical shaped device or a sub-hemispherical shaped device, and can be comprised of composite material or other materials. The first patient-specific jig may include at least three alignment members for attachment to specific portions of the jig based on the specific bone structure of the patient&#39;s coxal bone. The at least three alignment members may assist with proper alignment of the first patient-specific jig in the patient&#39;s acetabulum during surgery. The three alignment members may include first, second, and third alignment members that are positioned at specific outer portions of the first patient-specific jig. 
         [0011]    In some embodiments, the first, second, and third alignment members are designed and adapted to be hooked on or engaged with (or otherwise positioned at) particular portions of the coxal bone adjacent to the acetabulum to stabilize and properly orient the first patient-specific jig into the acetabulum during surgery. The first alignment member may be positioned on the first patient-specific jig to engage a particular portion of the medial rim of the acetabulum of the coxal bone. The second alignment member may be positioned on the first patient-specific jig to engage a particular portion of the greater sciatic notch of the coxal bone. The third alignment member may be positioned on the first patient-specific jig to engage a particular portion of the obturator foramen of the coxal bone. These alignment members may contact any three areas of bone peripheral to the acetabulum. Thus, the first patient-specific jig includes three reference points/members, specific to the patient&#39;s acetabulum of the coxal bone, to properly align the first patient-specific jig in the acetabulum during surgery and provide for proper orientation of the reaming machine when resurfacing the acetabulum. 
         [0012]    The three alignment members may each comprise a pair of hooks or other devices that provide sufficient engagement with the particular portions of the coxal bone, as determined by the surgeon during preoperation. A person having ordinary skill in the art when reviewing this disclosure will understand that the three alignment members may be secured or removably attached or abutted to the first patient-specific jig by any currently or later known suitable means or attachment methods. The three alignment members may pivot, swivel or otherwise move relative to the first patient-specific jig, or they may be relatively immovable or inflexible to provide sufficient force against respective portions of the coxal bone to ensure proper orientation of the first patient-specific jig. 
         [0013]    An aperture may be provided radially into or through the first patient-specific jig. The aperture is adapted to receive a guide pin or post extension through the aperture during surgery. The guide pin or extension is placed into the aperture and is removably secured to the coxal bone of the patient in a particular orientation and at a particular depth, as determined by the surgeon during preoperation. The first patient-specific jig is then removed while the guide post remains positioned in the coxal bone at the desired angle and position. The guide post may then serve as a guide for the reaming machine to accurately ream (resurface) the acetabulum to a predetermined depth and orientation for receiving the acetabular cup. The guide post and the reamer may have the same or similar central axes, as with conventional reaming machines and processes. In some embodiments the guide post may be removed prior to reaming and a surgeon at his discretion may use the guide post sinus tract as a guide to reaming without the guide post at a desired angle and to a desired depth. 
         [0014]    As discussed above, it is critical to ream the acetabulum accurately and as determined during preoperation. Accordingly, the second patient-specific jig may be provided to assist in determining accurate reaming and proper alignment of the acetabular cup before the cup is implanted into the patient&#39;s acetabulum. As indicated below, a third patient-specific jig may also be used to progressively prepare the acetabulum to properly receive the prosthetic acetabular cup. 
         [0015]    The second patient-specific jig may be designed and manufactured based on the second patient-specific male portion, but it may also be based on the first patient-specific male portion. The second patient-specific jig may include at least three alignment members, which may be based on the same or similar positions as the first, second, and third alignment members of the first patient-specific jig, or the positions may be different depending upon the patient&#39;s anatomy. The second patient-specific jig may also include an aperture having the same or similar position and orientation as the aperture in the first patient-specific jig, or it may be different. The second patient-specific jig may also have an axial length that is greater than a corresponding axial length of the first patient-specific jig due to the fact that the second patient-specific jig is utilized after some or all of the reaming of the acetabulum has occurred. 
         [0016]    After the surgeon has removed the first patient-specific jig and reamed the acetabulum to a predetermined depth and orientation, the reamer device is removed from the acetabulum and the guide post may remain attached to the coxal bone or, in some instances, may be removed. The surgeon may then position the second patient-specific jig into the reamed acetabulum without a pin or, alternatively, onto the original guide pin or post extension, or alternatively over a different pin or post extension used to align the second patient-specific jig. Using the particular shape and size of the second patient-specific jig and, where applicable, the alignment of the aperture through the jig, the surgeon may then rotate and position the second patient-specific jig in the reamed acetabulum to determine whether additional reaming is required in one or more quadrants, or whether the acetabulum has been reamed accurately to receive the prosthetic acetabular cup. In furtherance of such determination, the surgeon may also utilize the alignment members attached to the second patient-specific jig, if they were designed and manufactured for attachment to the jig; it may be that the aperture and the shape of the second patient-specific jig is sufficient for purposes of accurate alignment of the prosthetic acetabular cup. 
         [0017]    In some instances, if adequate remaining in any direction has not been accomplished and confirmed with only one or two jigs, there may be a need for additional reaming after which a third jig may be used. The third patient specific jig may be similar or different in regards to alignment members and guide post aperture orientation as the first and/or second patient specific jigs. 
         [0018]    Once accurate reaming is accomplished through utilizing some or all of the above described devices and methods, the surgeon may then implant or secure the acetabular prosthetic cup to the reamed acetabulum in a traditional manner, such as with or without screws and with or without cement and with or without use of a guide pin or post extension. 
         [0019]    The predetermined orientation of the apertures and the alignment members of both the first and second (and, as applicable, third) patient-specific jigs may provide the surgeon with a quick, accurate means to properly resurface the acetabulum without the use of additional devices and machines. This is possible because the positions of the alignment members of the first, second and third patient-specific jigs are based upon the patient&#39;s bone structure, thereby providing three reference points to accurately utilize the first jig, the guide post, the reamer, and the second and third jigs, as planned during preoperation based upon the 3D modeling images of the patient. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0020]      FIGS. 1-4  are flow diagrams illustrating steps for pre-operative imaging and planning for a joint replacement procedure, according to an aspect of the present invention. 
           [0021]      FIG. 4A  schematically illustrates a system for carrying out the steps of  FIGS. 1-4 . 
           [0022]      FIGS. 5 and 6  are flow diagrams illustrating steps for performing a joint replacement procedure, according to an aspect of the present invention. 
           [0023]      FIG. 7  is a front view of a pelvic bone. 
           [0024]      FIG. 8  is a top view of a prosthetic implant seated in the pelvic bone of  FIG. 7 . 
           [0025]      FIG. 9A  is a top view of a patient-specific jig mounted on the pelvic bone of  FIG. 7  according to one embodiment. 
           [0026]      FIG. 9B  is a partial cross-sectional view of the pelvic bone of  FIG. 7  and a side view of the patient-specific jig of  FIG. 9A . 
           [0027]      FIG. 10A  is an isometric view of a first patient-specific jig according to one embodiment. 
           [0028]      FIG. 10B  is an elevational view of the first patient-specific jig of  FIG. 10A . 
           [0029]      FIG. 11A  is an isometric view of a second patient-specific jig according to one embodiment. 
           [0030]      FIG. 11B  is an elevational view of the second patient-specific jig of  FIG. 11A . 
           [0031]      FIG. 12A  is an isometric view of a third patient-specific jig according to one embodiment. 
           [0032]      FIG. 12B  is an elevational view of the third patient-specific jig of  FIG. 8 . 
           [0033]      FIG. 13A  is a side view of a first patient-specific jig positioned in an acetabulum and a guide post positioned through said jig and secured to the acetabulum. 
           [0034]      FIG. 13B  is a side view of the pelvic bone showing the first patient-specific jig positioned in the acetabulum. 
           [0035]      FIG. 14  is a cross-sectional view of a reaming tool positioned in the acetabulum. 
           [0036]      FIG. 15A  is a side view of a second patient-specific jig positioned in an acetabulum and a supplemental guide post positioned through said jig and secured to the acetabulum. 
           [0037]      FIG. 15B  is a side view of the pelvic bone showing the second patient-specific jig positioned in the acetabulum  15 A. 
           [0038]      FIG. 16  is a cross-sectional view of a reaming tool positioned in the acetabulum. 
           [0039]      FIG. 17A  is a side view of a third patient-specific jig positioned in the acetabulum and the supplemental guide post of  FIG. 15A . 
           [0040]      FIG. 17B  is a top view of the third patient-specific jig positioned in the acetabulum as shown in  FIG. 17A . 
           [0041]      FIG. 18  is an isometric view of an impactor tool used to install a prosthetic implant in a reamed acetabulum according to one aspect of the present disclosure. 
           [0042]      FIG. 19  is an isometric view of a cannulated acetabular impactor according to an embodiment of the present invention. 
           [0043]      FIG. 20  is an end view of the cannulated acetabular impactor of  FIG. 19 . 
           [0044]      FIG. 21  is a partial cross-sectional view of a prosthetic implant in a reamed acetabulum that is being installed with the impactor tool of  FIG. 18  and the cannulated actabular impactor of  FIG. 19 , according to one aspect of the present disclosure. 
           [0045]      FIG. 22  is a cross-sectional view of a portion of another cannulated acetabular impactor according to an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    As mentioned above, the methods and systems of the present invention are based at least in part on pre-operating (pre-operative) imaging and at least in part on orthopedic surgical procedures based upon the pre-operative methods and systems. As is understood in the art, pre-operative imaging has a number of different purposes and generally is performed in order to subsequently guide the surgeon during the surgical procedure, allow for patient-specific tools and/or implants to be formed, etc. The present disclosure is part of a system for designing and constructing one or more patient-specific jigs for use in an orthopedic surgical procedure in which an acetabular component is prepared, orientated and implanted. The referenced systems and methods are now described more fully with reference to the accompanying drawings, in which one or more illustrated embodiments and/or arrangements of the systems and methods are shown. Aspects of the present systems and methods can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.), or an embodiment combining software and hardware. One of skill in the art can appreciate that a software process can be transformed into an equivalent hardware structure, and a hardware structure can itself be transformed into an equivalent software process. Thus, the selection of a hardware implementation versus a software implementation is one of design choice and left to the implementer. Throughout this disclosure, the term “prosthetic implant” and “acetabular component” refer to cup-shaped implants that are installed into patients during hip replacement surgery. 
         [0047]      FIGS. 1-4  are flow diagrams illustrating methods pertaining to pre-operative imaging and planning according to aspects of the present invention.  FIG. 4A  shows a system for carrying out the methods of the present disclosure, such as those described with reference to  FIGS. 1-4 . As a preliminary matter,  FIG. 4A  is a simplified system  410  of devices that may be used to carry out the methods of the present disclosure. The system  410  comprises a computing system  412  coupled to an imaging system  414  that captures and transmits patient image data to the computing system  412 . The computing system  412  processes such data and transmits the data to the display device  416  for display of images and other data. An input device  418  receives input from a computer or an operator (such as a surgeon) and transmits inputted information to the computing system  412  for processing. Such systems are well known in the art and will not be described in greater detail. The imaging system  412  may include a bone imaging machine for forming three dimensional image data from bone structure of a patient. The computing system  412  may include a patient-specific device generator for processing and generating images, and a patient-specific device converter for generating design control data. A manufacturing machine  420  receives the control data from the computing system  412  for making patient-specific various jigs. 
         [0048]    In  FIG. 1 , a method  100  according to an embodiment starts at  101 . At  102 , a bone imaging machine generates a bone surface image from three dimensional image data from bone structure of a patient. At  104 , a patient-specific device generator generates a prosthesis implant image superimposed in an acetabulum of the bone surface image. The implant in the image is positioned in its final, implanted position and orientation, regardless of the state of the patient&#39;s bone. The jigs created from the present invention will be designed to modify the bone such that the implant will be properly positioned at the end of the procedure. 
         [0049]    At  106 , the patient-specific device generator generates a first-patient specific jig image superimposed proximate the acetabulum of the bone surface image according to the installation position. At  108 , a patient-specific device converter generates control data from the first patient-specific jig image and ends or moves to  110 . At  110 , the patient-specific device generator generates a second patient-specific jig image superimposed in the acetabulum of the bone surface image and ends or moves to  112 . At step  112 , the patient-specific device generator generates a third patient-specific jig image superimposed in the acetabulum of the bone surface image and ends. 
         [0050]      FIG. 2  shows a method  200  according to an aspect of the present disclosure. At  202 , a patient-specific device generator generates a guide post image at least partially positioned through an acetabulum of the bone surface image. At  204 , the patient-specific device generator generates a first patient-specific jig image superimposed in the acetabulum of the bone surface image according to the installation position. At  206 , the patient-specific device generator generates an aperture image through the body image of the second patient-specific jig image and ends. 
         [0051]      FIG. 3  shows a method  300  according to an aspect of the present disclosure. At  302 , a patient-specific device generator generates a guide post image at least partially positioned through an acetabulum of the bone surface image. At  304 , the patient-specific device generator generates a second patient-specific jig image superimposed in the acetabulum of the bone surface image according to the installation position. At  306 , the patient-specific device generator generates an aperture image through the body image of the first patient-specific jig image and ends. 
         [0052]      FIG. 4  shows a method  400  according to an aspect of the present disclosure. At  402 , a patient-specific device generator generates a guide post image at least partially positioned through an acetabulum of the bone surface image. At  404 , the patient-specific device generator generates a third patient-specific jig image superimposed in the acetabulum of the bone surface image according to the installation position. At  306 , the patient-specific device generator generates an aperture image through the body image of the third patient-specific jig image and ends. 
         [0053]    As discussed above,  FIG. 4A  shows a system  410  for carrying out the methods of  FIGS. 1-4  according to some aspects of the present disclosure. The computing system  412  may include instructions in the form of computer software for automatically generating images of prosthesis implants in final installation positions on the bone structure images and for automatically generating various guide post images and jig images designed for use during surgery on the particular patient. In some aspects, it may be necessary for the surgeon during preoperative planning to input information into the input device  418  for creating or altering guide post and jig images for a particular patient based on the surgeon&#39;s understanding of the particular bone structure of the patient as displayed on the display device  416 . 
         [0054]      FIGS. 5 and 6  are flow diagrams of methods pertaining to operative surgery according to aspects of the present disclosure. The methods of  FIGS. 5 and 6  may be carried out by a surgeon or by a machine, or by both. Moreover, the surgeon may utilize some or all of the devices discussed with reference to  FIGS. 1-4A  during surgery, such as viewing the preoperative images displayed on the display device while operating on a patient. 
         [0055]    In  FIG. 5 , a method  500  according to an aspect starts at  501 . At  502 , a first patient-specific jig is positioned in an acetabulum of a patient. The first patient-specific jig is formed according to a predetermined installation position of a prosthesis implant to be secured to the patient. At  504 , each of three alignment members is engaged with a corresponding pre-selected area on a coxal bone and adjacent the acetabulum of the patient. At  506 , a guide post is positioned through the aperture of the first patient-specific jig and is secured into the coxal bone of the patient. At  508 , the first patient-specific jig is removed from the guide post. At  510 , bone material from the acetabulum is reamed with aid of a reaming machine. At  512 , it is determined whether the reaming machine has reached an installation reference point of the installation position; this may be determined by the surgeon or by a measuring device or other device to determine the depth of bone that was reamed. If the reaming machine has reached an installation reference point, at  514  the guide post is removed and the prosthesis implant is installed in the patient, then ends. If the reaming machine has not reached an installation reference point, at  516  the guide post is removed and a second patient-specific jig is positioned in the reamed acetabulum of the patient, then to step  602  in  FIG. 6 . As further discussed below, in some aspects the guide post is not removed and remains secured to the patient until the prosthesis implant is installed. 
         [0056]    At step  602 , three alignment members of the second patient-specific jig are respectively engaged with predefined selected areas proximate the acetabulum of the patient. At  604 , a supplemental guide post is positioned through the aperture of the second patient-specific jig and is secured into the coxal bone of the patient. At  606 , the second patient-specific jig is removed from the supplemental guide post and the acetabulum. At  608 , the acetabulum is reamed with aid of a reaming machine. In some instances the guide post can be removed prior to reaming and the sinus tract in the bone from the guide post is used as a visual guide to ream at a desired orientation and to a desired depth. At  610 , a third patient-specific jig is positioned in the reamed acetabulum of the patient. At  612 , it is determined whether all three alignment members of the third patient-specific jig are engaged to respective selected areas proximate the acetabulum of the patient. If yes, at  616  the supplemental guide post may or may not be removed and the prosthesis implant is secured to the reamed acetabulum and then ends. If no, the method returns to  608  and the operations are repeated until it is determined that all three alignment members of the third patient-specific jig are engaged to respective selected areas proximate the acetabulum of the patient so that the prosthesis implant may be installed in the patient. 
         [0057]      FIGS. 7 and 8  show an acetabular component  700  oriented an in an acetabulum  702  of a coxal bone  704  of a pelvic bone  706 . The acetabular component  700  is positioned according to an installation position  708 , which is in part determined by a prescribed anteversion angle and a prescribed inclination angle of the acetabular component  700 .  FIG. 7  shows a front view of the pelvic bone  706  and the acetabular component  700  positioned in the acetabulum  702  of the patient&#39;s right coxal bone  704 , and  FIG. 8  shows a lateral view of the right coxal bone  704  with the acetabular component  700  positioned in the acetabulum  702 . These figures illustrate the incorporation of steps discussed with reference to  FIGS. 1-4A  where the acetabular component  700  is a generated image that is superimposed over a generated image of bone structure (e.g., the coxal bone  704 ) of a patient to determine an installation position  708  of the acetabular component  700 . Determining the prescribed anteversion angle and the prescribed inclination angle for a particular patient involves techniques and calculations that are known in the art, and thus, will not be described in detail. Although not necessarily part of the preoperative planning, for purposes of illustration an installation axis P is shown on  FIG. 7   
         [0058]    Once the installation position  708  is determined, a reference point  710  is established that represents a particular point in the coxal bone  704  of the patient for purposes of determining the depth to which a reaming machine will ream bone material, which will be further discussed below. The reference point  710  may be considered a point on the tangential plane of a hemispherical shaped surface, such as the outer surface shape of the acetabular component  700 . 
         [0059]    With continued reference to  FIG. 8 , the coxal bone  704  includes (among many others) a medial rim  712 , a sciatic notch  714 , and an obturator foramen  716 , which all have various shapes and surfaces that are specific to each patient. 
         [0060]      FIGS. 9A and 9B  show a patient-specific jig  720  oriented in the acetabulum  702  of the coxal bone  704  according to the installation position  708  of the acetabular component  702 . These figures show a technique that incorporates steps of  FIGS. 1-4A  in that the patient-specific jig  720  is a generated image that is superimposed over the generated image of the bone structure of a patient. As a preliminary matter, the patient-specific jig  720  may be any one of the first, second, and third patient-specific jigs discussed with reference to  FIGS. 10A-15B  and elsewhere in this disclosure.  FIGS. 9A and 9B  are mere illustrations of one possible patient-specific jig  720 . 
         [0061]    The patient-specific jig  720  includes an aperture  722  and three alignment members  724   a ,  724   b ,  724   c . The aperture  722  is formed through the patient-specific jig  720  at an angle that corresponds to the installation position  708  of the acetabular component  700 . Depending upon the particular patient-specific jig  720  (i.e., the first, second, or third), the relative orientation of the aperture  722  may vary depending upon the required amount of bone to be removed and the particular required angle of a reaming head during operation, which is ultimately determined by the installation position  708  of the acetabular component  700 . The angles of the various apertures for the various jigs are discussed further below. 
         [0062]    The three alignment members  724   a ,  724   b ,  724   c  are attached to the patient-specific jig  720  at positions around a circumference end  726  (or distal end) of the patient-specific jig  720  depending upon the particular bone structure of the particular patient. The three alignment members  724   a ,  724   b ,  724   c  may be formed integral with the jig or may be attached to the jig with any suitable attachment means. The purpose of the three alignment members  724   a ,  724   b ,  724   c  help the surgeon: 1) determine the proper orientation of a guide post to be installed in the patient ( FIGS. 13A and 15A ), and/or 2) determine whether additional reaming of bone is necessary before utilizing another jig or before final installation of an acetabular component. In any event, depending on whether all of the three alignment members  724   a ,  724   b ,  724   c  of a particular patient-specific jig  720  are in contact with respective selected areas of the patient&#39;s bone during surgery when the particular jig is placed in the acetabulum  702 , corresponding information is conveyed to the surgeon. The surgeon will be able to determine the next appropriate steps during surgery, as further described below. 
         [0063]    The positions of the three alignment members  724   a ,  724   b ,  724   c  will depend on which particular jig (i.e., first, second, or third jigs) the three alignment members are attached to. However, the positions the three alignment members  724   a ,  724   b ,  724   c  may be the same on each jig depending on the preoperative requirements determined by the surgeon and the computing systems. In one example and as shown on  FIG. 9B , the first alignment member  724   a  is attached to the patient-specific jig  720  at an attachment portion  726   a , and the second alignment member  724   b  is attached to the patient-specific jig  720  at an attachment portion  726   b , and the third alignment member  724   c  is attached to the patient-specific jig  720  at an attachment portion  726   c . The position of the respective attachment portions  726   a ,  726   b ,  726   c  are determined during pre-operative imaging and planning steps. Accordingly, the three alignment members  724   a ,  724   b ,  724   c  extend from the circumference end  726  of the patient-specific jig  720  and are designed to contact certain selected areas of the coxal bone  704  depending on the bone structure of the patient. The first alignment member  724   a  contacts a selected area  728   a  of the medial rim  712 . The second alignment member  724   b  contacts a selected area  728   b  of the sciatic notch  714 . Finally, the third alignment member  724   c  contacts a selected area  728   c  inferiorally below the transverse acetabular ligament at the superior portion of the obturator foramen  716 . In some instances, such as when using the second and third jigs, the contact between the alignment members and the respective selected areas is dependent upon whether the surgeon has reamed enough bone. If not, at least one of the alignment members will not be in contact with the respective selected area, indicating that more bone needs to be removed, as further discussed below. 
         [0064]      FIGS. 10A and 10B  show a first patient-specific jig  730 .  FIGS. 11A and 11B  show a second patient-specific jig  744 .  FIGS. 12A and 12B  show a third patient-specific jig  754 . These figures represent that the patient-specific jigs are generated images based on the installation position of the acetabulum component and based on the bone structure of the patient. Some or all of the patient-specific jigs are formed by a machine based on the generated images, as further discussed elsewhere in this disclosure. In some cases, only a first patient-specific is generated and created in instances where very little bone reaming is required, for example. 
         [0065]      FIG. 10A  shows an isometric view of a first patient-specific jig  730  and  FIG. 10B  shows a side elevational view of  FIG. 10A . The first patient-specific jig  730  includes three alignment members  732   a ,  732   b ,  732   c  that extend from a circumference end  734  of the first patient-specific jig  730  at positions to contact certain selected areas of the coxal bone (see  FIG. 9A  (generically) and  FIG. 13B  (specifically)). The first alignment member  732   a  is attached to the patient-specific jig  730  at an attachment portion  736   a , and the second alignment member  732   b  is attached to the first patient-specific jig  730  at an attachment portion  736   b , and the third alignment member  732   c  is attached to the patient-specific jig  730  at an attachment portion  736   c . The angle and position of each alignment member  732   a ,  732   b ,  732   c  relative to the circumference end  734  is determined according to the particular position and surface of the selected areas of the coxal bone of the patient that the alignment members  732   a ,  732   b ,  732   c  are designed to contact during use of the first patient-specific jig  730  during operation. Each alignment member  732   a ,  732   b ,  732   c  includes an engagement portion  738   a ,  738   b ,  738   c , respectively, which is the portion of the alignment member that contacts respective selected areas of the coxal bone  704 . See  FIGS. 13A  and  13 B for illustrations of the position of each alignment members  732   a ,  732   b ,  732   c  relative to the first patient-specific jig  730  and the selected areas of the patient&#39;s coxal bone  704 . 
         [0066]    The first patient-specific jig  730  includes an aperture  740  that extends from a reference end  742  to the circumference end  734  of the first patient-specific jig  730 . The aperture  740  is sized and configured to receive a guide post positioned in a patient ( FIG. 13A ). As further described below, the guide post is positioned according to the installation position  708  of the acetabular component  700  ( FIGS. 7 and 8 ). The first patient-specific jig  730  includes a height H1, which is selected so that the reference end  742  does not contact an unreamed acetabulum at the beginning stages of surgery. This is discussed further below. 
         [0067]      FIG. 11A  shows an isometric view of a second patient-specific jig  744  and  FIG. 11B  shows a side elevational view of  FIG. 11A . The second patient-specific jig  744  includes three alignment members  746   a ,  746   b ,  746   c  that extend from a circumference end  748  of the second patient-specific jig  744  at positions to contact certain selected areas of the coxal bone (see  FIG. 9A  (generically) and  FIG. 15B  (specifically)). The alignment members  746   a ,  746   b ,  746   c  are attached to the second patient-specific jig  744  at respective attachment portions  750   a ,  750   b ,  750   c , similar to the first patient-specific jig  730 . The angle and position of each alignment member  746   a ,  746   b ,  746   c  relative to the circumference end  748  is determined according to the particular position and surface of the selected areas of the coxal bone of the patient that the alignment members  746   a ,  746   b ,  746   c  are designed to contact during use of the second patient-specific jig  744  during operation. Such angle and position of each alignment member  746   a ,  746   b ,  746   c  may be the same as or different than that of the alignment members of the first patient-specific jig  730  of  FIG. 10A . Each alignment member  746   a ,  746   b ,  746   c  includes an engagement portion  748   a ,  748   b ,  748   c , respectively, which is the portion of the alignment member that contacts respective selected areas of the coxal bone  704 . See  FIGS. 15A and 15B  for illustrations of the position of each alignment member  746   a ,  746   b ,  746   c  relative to the second patient-specific jig  744  and the selected areas of the patient&#39;s coxal bone  704 . 
         [0068]    The second patient-specific jig  744  includes an aperture  750  that extends from a reference end  752  to the circumference end  748  of the second patient-specific jig  744 . The aperture  750  is sized and configured to receive a supplemental guide post positioned in a patient ( FIG. 15A ). As further described below, the supplemental guide post is positioned according to the installation position  708  of the acetabular component  700  ( FIGS. 7 and 8 ). The second patient-specific jig  744  includes a height H2, which is selected so that, if the reference end  752  contacts a reamed acebaulum, and if at least one of the alignment members  746   a ,  746   b ,  746   c  is not in contact with a respective selected area of the coxal bone, the surgeon will know that additional reaming is necessary before installing the supplemental guide post and placing the final acetabular prosthesis. This is discussed further below. Understandably, height H2 can be greater than height H1, in part because bone is reamed between usage of the first and second jigs. 
         [0069]      FIG. 12A  shows an isometric view of a third patient-specific jig  754  and  FIG. 12B  shows a side elevational view of  FIG. 12A . The third patient-specific jig  754  includes three alignment members  756   a ,  756   b ,  756   c  that extend from a circumference end  758  of the third patient-specific jig  754  at positions to contact certain selected areas of the coxal bone (see  FIG. 9A  (generically) and  FIG. 17B  (specifically)). The alignment members  756   a ,  756   b ,  756   c  are attached to the third patient-specific jig  754  at respective attachment portions  760   a ,  760   b ,  760   c , similar to the first patient-specific jig  730 . The angle and position of each alignment member  756   a ,  756   b ,  756   c  relative to the circumference end  758  is determined according to the particular position and surface of the selected areas of the coxal bone of the patient that the alignment members  756   a ,  756   b ,  756   c  are designed contact during use of the third patient-specific jig  754  during operation. Such angle and position of each alignment member  756   a ,  756   b ,  756   c  may be the same or different to that of the alignment members of the first and second patient-specific jigs of  FIGS. 10A and 11A . Each alignment member  756   a ,  756   b ,  756   c  includes an engagement portion  762   a ,  762   b ,  762   c , respectively, which is the portion of the alignment member that contacts respective selected areas of the coxal bone  704 . See  FIGS. 17A and 17B  for illustrations of the position of each alignment members  756   a ,  756   b ,  756   c  relative to the third patient-specific jig  754  and the selected areas of the patient&#39;s coxal bone  704 . 
         [0070]    The third patient-specific jig  754  includes an aperture  764  that extends from a reference end  766  to the circumference end  758  of the third patient-specific jig  754 . The aperture  764  is sized and configured to receive the supplemental guide post positioned in a patient ( FIG. 17A ). As further described below, the supplemental guide post is positioned according to the installation position  708  of the acetabular component  700  ( FIGS. 7 and 8 ). The third patient-specific jig  754  includes a height H3, which is selected so that, if the reference end  766  contacts a reamed acetabulum, thereby causing at least one of the alignment members  756   a ,  756   b ,  756   c  to not be in contact with a respective selected area of the coxal bone, the surgeon will know that additional reaming is necessary before installing the acetabular component  700  in the patient. This is discussed further below. Understandably, height H3 can be greater than height H2 because bone is reamed between usage of the second and third jigs, and because the second patient-specific jig is used for purposes of positioning the supplemental guide post while the third patient-specific jig is used for purposes of determining whether additional reaming is necessary before installing the acetabular component  700  in the patient. 
         [0071]    It will be appreciated that each or all of the alignment members of any one of the patient-specific jigs may be formed in various configuration and shapes. For example, an alignment member may be an arc shaped or other non-linear shaped member, or it may have two or more angles surfaces. The exact shape, position, and alignment of each alignment member is determined by the surgeon and the computing system during preoperative planning depending upon the specific bone structure of the patient and the installation position of the acetabulum component. 
         [0072]      FIGS. 13A and 13B  show the first patient-specific jig  730  positioned in an un-reamed acetabulum  703  of the patient, and  FIG. 14  shows a reaming tool  768  positioned in the acetabulum  703  and ready to ream bone material. These figures show a technique that incorporates the preoperative steps of  FIGS. 1-4A  in that the first patient-specific jig  730  and a guide post  770  are generated images that are superimposed over the generated image of the bone structure of a patient. These figures also show a technique that incorporates the operative steps practiced by a surgeon on a patient, such as described with reference to  FIGS. 5 and 6 . 
         [0073]    During preoperative planning and with reference to  FIGS. 9A and 9B , a generated image of an acetabular component  700  is imposed over the bone structure image, which ultimately shows the installation position  708  of the acetabular component  700 . Based on such installation position  708 , the computer system determines, with input from the surgeon, the exact position of the guide post  770  to be installed in the patient during early stages of operation. The guide post  770  will be the guide for the position of the first patient-specific jig  730  and the reaming machine  768 . Preferably, the guide post  770  is positioned substantially perpendicular to a central axis of the acetabular component  700  to be later installed in the patient; however, the angle of the guide post  770  relative to the acetabular component  700  may vary depending upon the preoperative surgery analysis by the computer system and the surgeon based on patient requirements. Once the orientation of the guide post  770  is established and displayed as a generated image, an image is generated of the first patient-specific jig  730 . As noted above, the purpose of the first patient-specific jig  730  is to establish the exact position of the guide post  770  to be installed in the patient during surgery. Accordingly, the reference end  742  of the first patient-specific jig  730  is designed to make contact with the un-reamed acetabulum  703 . The three alignment members  732   a ,  732   b ,  732   c  are designed to contact respective selected areas of the coxal bone  704  adjacent the acetabulum  703 . 
         [0074]    With particular reference to  FIG. 13B , during surgery the surgeon inserts the first patient-specific jig  730  into the acetabulum  703  and rotates or otherwise orients the first patient-specific jig  730  in the patient until all three alignment members  732   a ,  732   b ,  732   c  are in contact with respective selected areas  772   a ,  772   b ,  772   c  of the coxal bone  704 . Once the first patient-specific jig  730  is properly oriented, the surgeon inserts the guide post  770  through the aperture  740  and screws the guide post  770  into the bone (typically 2 mm to 20 mm deep). Thus, the guide post  770  will be installed at the exact position determined during preoperative planning and according to the installation position of the acetabular component  700 . The first patient-specific jig  730  may then be removed and a reaming machine  768  may be used to remove bone material from the patient, either over the guide post or without it in place. 
         [0075]      FIG. 14  illustrates the reaming machine  768  used for such purpose. The reaming machine  768  includes a reaming head  774 , which may be a detachable head of a selected size corresponding to the size of the acetabular component  700  to be installed. The reaming head  774  includes a guide aperture  776  that slidably receives the guide post  770 . The reaming head  774  reams bone with a consistent axial motion in a direction depicted by Arrow A because the guide aperture  776  includes a central axis coextensive with a central axis of the guide post  770  and because the guide aperture  776  closely receives the guide post  770 . Such reaming heads with a guide aperture and methods of using such reaming heads with a guide post in a patient are well known in the art and will not be described in greater detail. 
         [0076]      FIGS. 15A and 15B  show the second patient-specific jig  744  positioned in a reamed acetabulum  705  of the patient, and  FIG. 16  shows a reaming tool  768  ready to ream additional bone material. These figures show a technique that incorporates the preoperative steps in that the second patient-specific jig  744  is a generated image that is superimposed over the generated image of the bone structure of a patient. These figures also show a technique that incorporates the operative steps practiced by a surgeon on a patient. 
         [0077]      FIG. 15A  shows the reamed acetabulum  705  as the result of the surgeon reaming a portion of the acetabulum  703  to a desired depth. In some instances, the surgeon will ream a couple millimeters of bone and will have reached the reference point  710  ( FIG. 7 ) such that bone reaming is completed and the acetabular component  700  can be installed in the patient. In other instances, additional bone reaming is necessary to a depth depending upon the installation position  708  for a particular patient as determined during preoperative planning. When it is determined that additional bone reaming is necessary, in some instances the guide post  770  of  FIG. 13A  remains installed in the patient and the second patient-specific jig  744  is utilized to determine if additional bone reaming is necessary; this is accomplished by inserting the second patient-specific jig  744  into the reamed acetabulum  705  over the guide post  770  and determining whether the three alignment member  746   a ,  746   b ,  746   c  are all in contact with selected areas  772   a ,  772   b ,  772   c  of the coxal bone  704 . If not, the surgeon may utilize the reaming machine  768  of  FIG. 14  and ream additional bone material. The surgeon may continue to check the depth of the reamed acetabulum  705  by utilizing the second patient-specific jig  744  as noted above until all three alignment members  746   a ,  746   b ,  746   c  are in contact with the selected areas  772   a ,  772   b ,  772   c  of the coxal bone  704 . Once this is achieved, the surgeon will know with accurate precision that the reference point  710  has been reached and at the desired angle for accurate installation of the acetabular component  700  in the patient. The surgeon may then install the acetabular component  700  in the patient utilizing known techniques in the art. In the current method, a guide post may be utilized over which the acetabular component  700  may be more accurately placed than with standard techniques. 
         [0078]    In other instances and where additional bone reaming is necessary but at a different angle than with respect to  FIG. 14  according to preoperative planning, the guide post  770  is removed from the patient and a supplemental guide post  778  is installed in the patient to guide the reaming machine  768  at a different angle than the original guide post  770 . In some instances the supplemental guide pst  778  may be removed prior to reaming and the sinus tract in bone may guide the surgeon to ream at an appropriate angle and to an appropriate depth. Such operative steps are determined by the surgeon, with the use of the computing system, during preoperative planning. For purposes of illustration and as one example,  FIGS. 15A and 15B  show the supplemental guide post  778  installed in the patient at a different angle than the guide post  770  of  FIGS. 13A and 14 . Accordingly, once the bone is reamed as described with reference to  FIG. 14 , the guide post  770  is removed and the second patient-specific jig  744  is placed into the reamed acetabulum  705 . Similar to the first patient-specific jig  730 , the second patient-specific jig  744  is utilized to determine the orientation of the supplemental guide post  778  to be installed in the patient. Thus, the surgeon inserts the second patient-specific jig  744  into the reamed acetabulum  705  and rotates or otherwise orients the second patient-specific jig  744  in the patient until all three alignment members  746   a ,  746   b ,  746   c  are in contact with respective selected areas  772   a ,  772   b ,  772   c  of the coxal bone  704 , as depicted on  FIGS. 15A and 15B . Once the second patient-specific jig  744  is properly oriented, the surgeon inserts the supplemental guide post  778  through the aperture  750  and the threads of the supplemental guide post  778  engage the bone. Thus, the supplemental guide post  778  will be installed at the exact position determined during preoperative planning and according to the installation position of the acetabular component  700 . The second patient-specific jig  778  may then be removed and a reaming machine  768  may be used to remove additional bone material from the patient, with or without the guide post in place. 
         [0079]      FIG. 16  illustrates the reaming machine  768  used for such purpose. The reaming machine  768  includes a supplemental reaming head  780 , which may be a detachable head of a selected size corresponding to the size of the acetabular component  700  to be installed. The supplemental reaming head  780  may be smaller in size than the reaming head  774  of  FIG. 14 , or it may be the same size. The supplemental reaming head  780  may include a guide aperture  782  that slidably receives the supplemental guide post  778 . The supplemental reaming head  780  reams bone with a consistent axial motion in a direction depicted by Arrow B because the guide aperture  782  includes a central axis coextensive with a central axis of the supplemental guide post  778  and because the guide aperture  782  closely receives the supplemental guide post  778 . Such reaming heads having a guide aperture are well known in the art and will not be described in greater detail. 
         [0080]      FIGS. 17A and 17B  show the third patient-specific jig  754  positioned in a reamed acetabulum  707  of the patient. These figures show a technique that incorporates the preoperative steps of  FIGS. 1-4A  in that the third patient-specific jig  754  is a generated image that is superimposed over the generated image of the bone structure of a patient. These figures also show a technique that incorporates the operative steps practiced by a surgeon on a patient disclosed herein. 
         [0081]      FIG. 17A  shows a reamed acetabulum  707  as the result of the surgeon reaming a portion of the acetabulum  705  to a desired depth, as discussed with reference to  FIG. 16 . In some instances, the surgeon will ream one or two millimeters of bone and utilize the third patient-specific jig  754  to determine whether additional bone reaming is necessary before final installation of the acetabular component in the patient, as determined during preoperative planning. Thus, the surgeon inserts the third patient-specific jig  754  into the reamed acetabulum  707 . If all three alignment members  756   a ,  756   b ,  756   c  are in contact with respective selected areas  784   a ,  784   b ,  784   c  of the coxal bone  704 , then the third patient-specific jig  754  has indicated that the reference point  710  of the installation position  708  has been reached, and therefore, bone reaming is completed. 
         [0082]    The surgeon will then install the acetabular component  700  according to known techniques or over a supplemental guide post using a cannulated acetabular impactor and mallet device as described herein. For purposes of discussion,  FIG. 17A  shows that alignment member  756   b  is not in contact with the selected area  784   b  adjacent to the native acetabulum. As such, the illustrated third patient-specific jig  754  indicates that the reference point  710  has not been reached, and, therefore, additional bone reaming is necessary. Accordingly, the surgeon reams bone with the reaming head  780 , utilizing the supplemental guide post  778  pilot hole or sinus tract from the removed guide post as a guide member, and then inserts the third patient-specific jig  754  to determine whether all three alignment members  756   a ,  756   b ,  756   c  are in contact with the coxal bone  704  and the reference point  710  ( FIG. 7 ) has been reached by the supplemental reaming head  780 . These processes continue until the acetabulum is reamed to the desired depth of the reference point, at which point the surgeon installs the acetabular component  700  in the patient, as shown on  FIG. 8 . 
         [0083]      FIGS. 18-22  show aspects of the present disclosure in which an impactor tool  800  is used to assist with installation of an acetabular component  700  in a reamed acetabulum  705  or  707 . Typically, a reamed acetabulum is reamed to have a radius slightly smaller than the radius of the acetabular component for a tight fit configuration. As such, the surgeon typically utilizes a mallet or other tool to impact the acetabular component into its final position. 
         [0084]    The impactor tool  800  includes a head  802  and a handle  804 . The head  802  includes a guide aperture  806  having a central axis X. During surgery and once the acetabulum is reamed to a desired depth, the acetabular component  700  is partially inserted into the reamed acetabulum. An elongated guide post  808  is installed in the coxal bone  704  and extends through a hole in the acetabular component  700 , as known in the art. A cannulated acetabular impactor device  810  includes a cannulated channel  812  that receives the elongated guide post  808 ; the cannulated acetabular impactor device  810  may be threaded or slidably received over the elongated guide post  808 . The cannulated acetabular impactor device  810  includes a distal end  814  biased against the cup portion of the acetabular component  700 , and a proximal end  816  with a surface  818  to be impacted by the impactor tool  800 . The guide aperture  806  of the impactor tool  800  slidably receives a portion of the guide post  808 . 
         [0085]    During installation of the actabular component  700 , the surgeon holds the handle  804  and slidably engages the guide aperture  806  of the impactor tool  800  with the guide post  808 . The surgeon then repeatedly impacts the surface  818  of the proximal end  816  of the cannulated acetabular impactor device  810  with the impactor tool  800 , causing an impacting force against the acetabular component  700 , until the acetabular component  700  is in its final position. Typically several impacts with the impactor tool  800  will suffice, and typically the surgeon can hear when the acetabular component  700  is seated flush against the acetabulum in its final position. One advantage of the impactor tool  800  is that impact against the elongated member  810  (and ultimately the acetabular component  700 ) occurs at approximately the same impact location upon each repeated impact with the tool  800 . Typically, the surgeon uses a mallet or hammer without the assistance of any guidance, which can result in improper installation of the acetabular component  700 . The guide aperture  806  of the impactor tool  800  ensures repeatable impact location and position of the impactor tool  800 , which reduces or eliminates the possibility for human error during repeated impacts with a mallet or hammer. 
         [0086]    The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments. 
         [0087]    These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.