Patent Publication Number: US-2007118139-A1

Title: System and method for bone resection

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      Not applicable  
     REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not applicable  
     SEQUENTIAL LISTING  
      Not applicable  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a method and system for performing bone resections in orthopedic surgeries, such as a total knee arthroplasty, using a surgical navigation system. More particularly, this invention relates to a less invasive technique for attaching tracking devices to boney structure.  
      2. Description of the Background of the Invention  
      Many orthopedic surgeries involve making bone cuts or osteotomy. These bone cuts must be made with precision because the implants that are placed over these bone cuts must function in a manner as close to healthy natural anatomy as possible. One current technique for precisely locating the osteotomy utilizes a surgical navigation system that enables the surgeon to guide the surgeon&#39;s instruments and tools to the precise location necessary to make the appropriate cuts. Orthopedic surgeons also utilize guides and jigs, either alone or with surgical navigation, to prepare boney structures with the precision necessary to receive an implant that will provide suitable mobility and quality of life to the patient.  
      One common type of orthopedic surgery is a total knee arthroplasty (TKA). This surgery involves the replacement of the entire knee joint with implants that replicate a healthy knee joint. The preparation of the femur and the tibia for the TKA procedure typically involves multiple bone cuts, each of which should be at an optimum angle for an optimum result. An alternative knee procedure is known as an unicompartmental knee arthroplasty (UKA). This procedure is used where only a portion of either the femur or the tibia is diseased. Only that portion or compartment is removed and a partial implant is inserted to replace the portion removed. One advantage is that the portion of the knee that is not diseased and is still functional will be used along with the implant to provide a more stable knee with potentially less complications. UKA procedures still require careful balancing of the restored portion of the knee so that the restored portion matches the natural portion closely to provide full functionality and mobility.  
      Surgical navigation systems have been used for surgeries that involve the precise location of instruments relative to a patient&#39;s anatomy. These systems were first used in brain operations that require the surgeon accurately place an instrument, probe or similar device in a precise predetermined location in a patient&#39;s brain. For orthopedic surgeries, the use of surgical navigation systems has not been as widespread. One reason is that surgical navigation systems require that tracking devices be affixed to the patient in a manner such that the tracking device is unlikely to move relative to the patient during the surgery. In orthopedic surgery, the surgeon will often manipulate the anatomy that is the subject of the surgery to determine range of motion both before and after the procedure. There also are other reasons that the patient and the subject anatomy cannot be fully immobilized during the procedure. This means that the tracking device necessary for surgical navigation must be firmly attached to the patient in a manner so that the tracking device will remain in a fixed relation to the patient&#39;s anatomy. The typical method of attachment is to affix these devices directly to a bone that is directly related to the particular surgery. For knee surgery, the location of the femur and the tibia at a minimum need to be tracked. The attachment method is typically a pin or rod type device with a point that is affixed in some fashion directly to the bone. While the risk to the patient is small, any time that the cortex of the bone is disturbed, there is an opportunity for infection or other complication. Also, depending on the size of the pin used, the insertion of these pins can add to patient discomfort and resistance. For some surgeons, these disadvantages outweigh the advantages of precisely locating the boney landmarks to prepare the joint, such as the knee joint, to receive the implants.  
     SUMMARY OF THE INVENTION  
      One aspect of the present invention relates to a method of performing an osteotomy of a bone using a surgical navigation system without attaching a bone tracking device directly to any portion of the bone that will remain after the osteotomy. This method comprises the steps of affixing a tracking device to a portion of the bone that will be removed during the osteotomy, the bone tracking device having a bone reference frame; determining an anatomical profile of the bone; and performing cuts using positional guidance from the surgical navigation system.  
      A further aspect of the present invention is directed to a method of balancing soft tissue of a joint during a joint arthroplasty using a surgical navigation system after the joint has been prepared to receive implants. This method comprises the steps of first mounting a first trial implant to the prepared joint and a second trial implant to the prepared joint; the first trial implant having a first tracking device attached to the first trial implant, and the second trial implant having a second tracking device attached to the second trial implant. The method also includes displaying joint alignment parameters based on a determined anatomical profile of the joint, and the position of the first tracking device and the second tracking device; and adjusting the soft tissue to balance the joint alignment parameters.  
      A still further aspect of the present invention relates to system to assist in the performance an osteotomy of a bone for a joint arthroplasty. The system comprises a surgical navigation system having a display; a fixation plate that can be attached to the bone at a location that will be removed during the osteotomy, and the fixation plate having an connection device. The system also includes a bone tracking device directly attached to the fixation plate, the bone tracking device having a bone reference frame, a cutting jig for the bone attached to the fixation plate by the connection device, the cutting jig having a jig tracking device directly attached to the cutting jig, the jig tracking device having a jig reference frame; and a fixation device to fix the cutting jig in place, wherein the cutting jig can be adjusted into position using the display and a previously determined anatomical profile of the bone.  
      A yet another aspect of the present invention is a method of balancing soft tissue of a knee during a knee arthroplasty using a surgical navigation system after a femur and a tibia have been prepared to receive implants. This method comprises the steps of mounting a trial femoral implant to the prepared femur and a trial tibial implant to the prepared tibia; the trial femoral implant having a femoral tracking device attached to the trial femoral implant, and the trial tibial implant having a tibial tracking device attached to the trial tibial implant; displaying leg alignment parameters based on a previously determined femoral anatomical profile and a previously determined tibial anatomical profile, and the position of the femoral tracking device and the tibial tracking device; and adjusting the soft tissue to balance the leg alignment parameters.  
      Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1 a  schematic depiction of a prior art TKA surgery using a surgical navigation system;  
       FIG. 2  is a side view of one embodiment of a fixation plate and tracking device attached to the distal femur;  
       FIG. 3  is a top isometric view of the fixation plate of  FIG. 2 ;  
       FIG. 4  is a side view similar to  FIG. 2  showing the use of a pointing device;  
       FIG. 5  is a side view of one embodiment of a fixation plate and tracking device attached to the proximal tibia;  
       FIG. 6  is a side view similar to  FIG. 2  showing the attachment of one embodiment of a cutting jig to the fixation plate;  
       FIG. 7  is a side view similar to  FIG. 2  showing the attachment of one embodiment of a tracking device to the cutting jig;  
       FIG. 8  is a screen shot from one embodiment of the surgical navigation system showing the positioning of the cutting jig;  
       FIG. 9  is a side view similar to  FIG. 2  showing one embodiment of affixing the cutting jig in place on the femur;  
       FIG. 10  is a view similar to  FIG. 7  schematically showing transferring the plate reference frame to the jig reference frame;  
       FIG. 11  is a view similar to  FIG. 2  showing the cutting jig attached to a femur that has been partly prepared to receive the implant;  
       FIG. 12  is a view similar to  FIG. 11  showing an optional step of verifying the bone cut;  
       FIG. 13  is a screen shot showing the location of the bone cut relative to the femur;  
       FIG. 14  is an isometric view of a further embodiment of a fixation plate;  
       FIG. 15  is a side view of the device of  FIG. 14  in place on a femur;  
       FIG. 16  is a view similar to  FIG. 15  showing the use of a pointer;  
       FIG. 17  is a view similar to  FIG. 15  showing the insertion of a guide pin;  
       FIG. 18  is a view similar to  FIG. 17  with the plate removed;  
       FIG. 19  is a view similar to  FIG. 18  showing the insertion of a screw;  
       FIG. 20  is a schematic view of a further embodiment of the present invention; and  
       FIG. 21  is a view similar to  FIG. 2  showing a still further embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 1  schematically shows a prior art method of preparing for TKA surgery using a surgical navigation computer  100  that includes a display  102  and a camera  104 . The camera  104  is capable of detecting the location and position of tracking devices  106 . One tracking device  106  is attached to femur  108  of a patient&#39;s leg  110  and the other tracking device  106  is attached to tibia  112  prior to performing TKA surgery on knee  114 . As noted above, each tracking device  106  is attached directly to the respective bone, femur  108  or tibia  112 , prior to surgery in a location remote from the surgical site for the TKA surgery. The tracking devices  106 , or at least the pin necessary to locate the tracking device  106 , will remain in place during the surgery and will be removed after the TKA surgery is completed.  
      The method and system of the present invention will be described in the context of a TKA procedure. However, the method and system of the present invention can also be used to perform any other surgical procedure where sections of the bones of a limb are removed as, e.g., wedge osteotomies in upper and lower extremities, UKA, hip replacement, and other similar procedures.  
      As shown in  FIGS. 2 and 3 , one embodiment of a fixation plate  130  is attached to a distal portion  132  of the femur  108 . The fixation plate  130  is held in place by a plurality of pins  134  that are inserted into the distal portion  132 . The fixation plate  130  has a base  136  with a proximal surface  138  and a distal surface  140 . Typically, the fixation plate  130  is pinned by pins  134  to medial condoyle  142  and lateral condoyle  144 . The pins  134  each pass through one of a series of holes  145  in the base  136 . The various holes  145  in the fixation plate  130  to facilitate the correct placement and attachment of the fixation plate  130  to the distal portion  132  of the femur  108 . It is not necessary that the fixation plate  130  be positioned in any particular location relative to the subject anatomy, in this case the distal portion  132  of the femur  108 . However, it is desirable for certain embodiments of the present invention to locate the fixation plate  130  either on or normal to a particular plane or axis of the subject anatomy. For instance, for the femur  108  the location of the fixation plate  130  parallel to the anterior-posterior axis of the femur will simplify the calculations necessary to properly place a cutting jig or other guide in position relative to the knee  114 .  
      A plate tracking device  146  is removably attached to the base  136  by an arm  148  and a docking device  150 . The docking device  150  allows the plate tracking device  146  to be removed when it is no longer needed and also holds the plate tracking device  146  in a fixed position relative to the fixation plate  130 . The plate tracking device  146  has a series of LEDs  152  that can be detected by the camera  104  of the surgical navigation computer  100  and has a three dimensional Cartesian reference frame  154 . The fixation plate  130  also has an attachment device  156  to enable the fixation plate  130  to be attached to other tools and devices, as will be discussed hereinafter.  
      In  FIG. 4 , a tracked pointer  160  is used to perform a portion of the anatomical survey of the femur  108 . The pointer  160  includes a tracking device (not shown) similar to plate tracking device  146 . The pointer tracking device can be either integral with the pointer  160  or attached using a similar attachment mechanism as shown in  FIG. 2 . The pointer  160  also has a pointer tip  162  and a pointer axis  164 . Both the location of the pointer tip  162  and the orientation of the pointer axis  164  have been previously calibrated to the pointer tracking device using known technology. The pointer tip  162  is used to trace the surface of the distal portion  132  of the femur  108  and record the shape of the distal portion  132  in memory of the surgical navigation computer  100 . Some anatomical structures of interest include the shape of the medial condoyle  142 , the shape of the lateral condoyle  144 , the anterior-posterior axis of the knee, also known as the Whitesides line, and possibly other features. In addition, by manipulating the femur  108 , the location of the plate tracking device  146  can be used by the surgical navigation computer  100  to determine the location of the center of the hip. This is done by taking a large number of readings of the location of the plate tracking device  146  as the femur  108  is manipulated and by calculating the most probable location of the hip center from this cloud of points. Also, the pointer  160  can determine the mechanical axis of the femur  108  using the pointer axis  164 . This is accomplished by the surgical navigation system  100  instructing the surgeon first, to locate the femoral center point, this is an anatomical landmark well known to surgeons, with the pointer tip  162 , second, to manipulate the pointer  160  so that the pointer axis  164  also points to the hip center, and third, to send a signal to the surgical navigation system  100 . At this point, the pointer axis  164  will then be located on the mechanical axis of the femur. In the past, a tracking device that was pinned directly to the femur  108  would have been used to provide the data to determine the location of the center of the hip and the mechanical axis. The structure of the femur  108  to which the fixation plate  130  has been pinned will be removed in preparation for the femoral implant insertion as will be seen later. Using the plate tracking device  146  to perform the anatomical survey will minimize additional intrusions into the femur  108  and will save operating room time because the need for placing extra anchoring devices is eliminated. At this point in the procedure, the surgeon has sufficient information from the anatomical survey done using the pointer  160  and the plate tracking device  146  and from pre-operative scans to determine the location of the modifications that need to be made to the femur  108 .  
      After the femur  108  has been surveyed, the tibia  112  is surveyed. As shown in  FIG. 5 , a tibial fixation plate  170  is attached to the tibia  112  using pins  172  that are inserted into a portion of the tibia  112  that will be removed in preparation of inserting the tibial implant. In a manner similar to the anatomical survey of the femur  108 , an anatomical survey of the tibia  112  is conducted. The locations of the tibia center, the tibial anterior-posterior axis, and both malleoli are determined by manipulating the tibia  112  and/or using the pointer  160 .  
      As shown in  FIG. 6 , a cutting jig  174  is attached to the attachment device  156  of the fixation plate  130  using a connector  176 . The connector  176  is capable of adjusting the relative position of the cutting jig  174  to the fixation plate  130 . The cutting jig  174  has a body  178 , a distal surface  180  and a series of pin apertures  182 . A plurality of fixation pins  184  are inserted into some of the pin apertures  182 , but the fixation pins  184  are not affixed to the femur  108  at this time.  
      The connector  176  includes a length adjustment screw  186  to modify the distance between the fixation plate  130  and the cutting jig  174  and an angle adjustment screw  188  to adjust the angle of the distal surface  180  relative to the fixation plate  130 . It is also possible to adjust the angle of the distal surface  180  relative to the frontal plane and the sagittal plane of the knee. The cutting jig  174  also has a guide slot  190  that can be used by the surgeon to guide the cuts to be made to the femur  108 . For the preparation of the tibia  112 , a similar device appropriate for the tibia  112  is attached to the tibial fixation plate  170 . The following steps described relative to the femur  108  are also applicable to the tibia  112 .  
      As shown in  FIG. 7 , a jig tracking device  192  similar to the plate tracking device  146  is attached to the distal surface  180  using an attachment coupling  194 . The jig tracking device  192  has a jig reference frame  196 . The jig reference frame  196  may be either the same as or different from the plate reference frame  154 . At this point, the cutting jig  174  has not been directly affixed to the femur  108  and can be moved to accurately position the cutting jig  174  to the precise location desired by the surgeon.  
       FIG. 8  is a screen shot  200  from the display  102  showing two windows, a first window  202  displaying a digitized frontal view  204  of the femur  108  and a second window  206  displaying a digitized lateral view  208  of the femur  108 . Overlaid on the view  204  is a goal axis and plane  210  and a current position of the cutting jig axis and plane  212  based on the location of the jig tracking device  192 . In a similar fashion, the second window  206  shows the lateral view of the same goal axis and plane  210  relative to the current position of the cutting jig axis and plane  212 , also based on the location of the jig tracking device  192 . As shown in the first window  202 , the current position of the cutting jig  174  will result in a varus alignment of 2.0°. The second window  206  shows a hyperextension of the knee of 16.0°. By manipulating the adjustment screws  186  and  188  and viewing the display  102 , the surgeon can position the cutting jig  174  in the proper position to achieve the desired surgical outcome. There will be similar screens for the tibia  112 .  
      As shown in  FIG. 9 , when the cutting jig  174  is located in the proper position relative to the femur  108 , the fixation pins  184  are then driven into the femur  108  using a tool  220 . At this point the cutting jig  174  is then held firmly in position by the fixation pins  184 . With the cutting jig  174  now firmly affixed to the femur  108 , if the plate reference frame  154  is different from the jig reference frame  196 , the surgical navigation computer  100  can replace the jig reference frame  196  with the plate reference frame  154 . This is schematically shown in  FIG. 10  by arrow  230 . After the transfer, the jig reference frame  196  is now a jig reference frame prime  196 ′. At this point, both the plate reference frame  154  and the jig reference frame prime  196 ′ are identical and the jig reference frame prime  196 ′ will provide the same positional data to the surgical navigation computer  100  as the plate reference frame  154  did previously. Also, the surgical navigation computer  100  will adjust all internal references to the jig reference frame  196  to the jig reference frame prime  196 ′. In this instance, the tracking device  192  is directly attached to the femur  108 , but it is attached to the cutting jig  174  without necessitating more invasion to the femur  108  than necessary to firmly affix the cutting jig  174  in position.  
      In  FIG. 11 , the fixation plate  130 , the connector  176  and both tracking devices  146  and  192  have been removed leaving only the cutting jig  174  attached to the femur. The view in  FIG. 11  is after the modifications have been made to the distal portion  132  of the femur  108  leaving a plateau  240  that is in line with either the guide slot  190  or the distal surface  180  of the cutting jig  174 . The bone modifications have been made in a conventional fashion using well known orthopedic tools and procedures  
      As shown in  FIG. 12 , the jig tracking device  192  has been reattached to the distal surface  180  of the cutting jig  174 . The coupling  194  used to re-attach the jig tracking device  192  ensures that the jig tracking device  192  is reattached in exactly the same position and orientation relative to the cutting jig  174 . This re-establishes the jig reference frame prime  196 ′ for the surgical navigation computer  100 . A plane tracking device  250  with a plane probe  252  attached is used to verify the accuracy of the bone modifications made. The plane probe  252  and the plane tracking device  250  have been calibrated so that the surgical navigation computer  100  knows the position and orientation of a plane surface  254  of the plane probe  252  relative to the position and orientation of the plane tracking device  250 .  
       FIG. 13  is a screen shot  260  similar to screen shot  200 . The left window  202  shows the relative position of the goal axis and plane  210  and the current axis and plane  208  based on data from the plane probe  252 . As shown, the current position as verified by the plane probe  252  will result in a varus alignment of 0.5° and a hyperextension of 4.0°. If this was the surgical goal, then the procedure can proceed to installing the implants in a conventional fashion. If further modifications are needed, they can be made at this point.  
       FIGS. 14 and 15  show a further embodiment of a fixation plate  300 . The fixation plate  300  has a body  302  with a distal surface  304  and a proximal surface  306 . There are a series of apertures  308  (not all are shown) through the body  302  to enable the use of pins  134  to attach the fixation plate  300  to the distal portion  132  of the femur  108  or to the proximal portion of the tibia  112 . A slot  310  is in the center of the body  302 . The slot  310  has a slide  312  movably mounted therein. With the normal positioning of the fixation plate  300  on the distal portion  132  of the femur  108 , the slot  310  will allow the slide  312  to move in the lateral medial direction. The slide  312  also has a slot  314  that is perpendicular to the axis of the slot  310  to move in the anterior-posterior direction. Mounted in the slot  314  is a universal joint  316  that has a cannula  318  passing through the universal joint  316  such that a probe can be inserted into the cannula  318  and pass through the cannula  318  and the slots  310  and  314 . The universal joint  316  also is capable of being fixed in position within the slot  314  in order to fix the angle of the cannula  318  relative to the fixation plate  300 . In a similar manner, the slide  312  has set screws  320  to fix the location of the slide  312  within the slot  310 . In addition, there is an arm  322  with a docking connector pin  324  affixed to the body  302  for mounting of the plate tracking device  146 .  
      The fixation plate  300  will be discussed relative to the use of the fixation plate  300  with the femur  108 . The fixation plate  300  can also be used with the tibia  112  in a similar manner. The fixation plate  300  is affixed to the distal portion  132  of the femur  108  using pins  134  affixed through apertures  308 . The proximal surface  306  will typically rest on the medial condoyle  142  and the lateral condoyle  144 . The precise location and orientation of the fixation plate  300  is not important. However, as discussed above, it may simplify positioning of other equipment relative to the fixation plate  300  to place the fixation plate  300  on a chosen anatomical reference plane or axis such as the anterior-posterior axis. The femur  108  is then surveyed, in part by manipulating the femur  108  so that the center of the hip joint can be located and the mechanical axis of the femur  108  can be determined. This is done in the same manner as described above and in accord with well known principles of anatomy. As described below, an intramedullary screw can be inserted later.  
      A pointing device  340  is then inserted through the cannula  318  and manipulated so that a pointer tip  342  points to a femoral center point  344 . Once the pointer tip  342  is located on the femoral center point  344 , the pointing device is manipulated and the slots  310  and  314  and the universal joint  316  allow a pointer axis  346  to move to point to the hip center. When the pointer axis  346  is pointing to the hip center and the pointer tip  342  is at the femoral center point  344  as shown in  FIG. 16 , the pointer axis  346  is aligned with a mechanical axis  348  of the femur  108 . At this point, the set screws  320  and the universal joint  316  are tightened to fix the cannula  318  such that the axis of the cannula  318  is aligned with the mechanical axis of the femur  108 .  
      Referring to FIGS.  17  to  19 , a guide pin  350  is inserted through the cannula  318  that has been fixed in place and aligned with the mechanical axis  348  of the femur  108  and the guide pin  350  is firmly attached to the femur  108 . A hollow self tapping screw  352  is placed over the guide pin  350  and also screwed firmly into position. The guide pin  350  is affixed to a part of the distal portion  132  that will be removed in preparation for the implant. The screw  352  has an exterior surface  354  that is the same diameter as a standard intramedullary rod. At this point, the surgical procedure can proceed by placing the cutting jig  170  over the screw  352  and performing procedures to align the cutting jig  170  without requiring the intrusion into the bone that normally accompanies the insertion of an intramedullary rod.  
      Because the hollow self tapping screw  352  was set along the mechanical axis of the femur  108  an adjustment of varus/valgus or flexion is not necessary if the cuts are to be made perpendicular to the mechanical axis. In this case, a much simpler jig can be used that only requires the adjustment of the jig&#39;s internal/external rotation to properly position the jig.  
      With reference to  FIG. 20 , after the femur  108  and/or the tibia  112  have been prepared to receive implants, a trial femoral implant  360  is placed onto the prepared femur  108 . The trial femoral implant  360  matches the shape and functionality of a final femoral implant that has been chosen based on the preparation of the femur  108  and the sizing requirement of the knee  114 . In addition, a trial tibial implant  362  that also replicates the final tibia implant is placed onto the prepared tibia  112 . The trial femoral implant  360  has a femoral trial tracking device  364  attached to the trial femoral implant  360  so that the trial femoral tracking device  364  does not interfere with the functionality and flexibility of the knee  114 . In a similar manner, a trial tibial tracking device  366  is attached to the trial tibial implant  362 . The display  104  will show a screen that includes the anatomical parameters that have been determined for the femur  108  and the tibia  112 . The trial femoral tracking device  364  and the trial tibial tracking device  366  will be recognized by the surgical navigation computer  100  and the reference frames for these two tracking devices will be matched to the prior femoral reference plane prime  196 ′ and the similarly determined tibial reference frame. The knee  114  will be manipulated to test the functionality and stability of the proposed implants using well known techniques. Based on the results of the manipulation, adjustments can be made, if needed, in an appropriate fashion to the soft tissue envelope of the knee  114 . Once the functionality of the restored knee  114  has been optimized, the trial femoral implant  360  and the trial tibial implant  362  will be replaced by the final implants that will be affixed to the femur and the tibia using conventional methods.  
      There is also an alternative method to use the trial femoral implant  360  and the trial tibial implant  362  in a knee  114  that has been prepared without the use of the surgical navigation system  100 . In this case, the trial femoral implant  360  and the trial tibial implant  362  are placed in a knee  114  that has been prepared in a conventional fashion. The trial femoral tracking device  364  is attached to the trial femoral implant  360 , and the trial tibial tracking device  366  is attached to the trial tibial implant  362 . The knee  114  and the femur  108  and the tibia  112  are manipulated to determine the necessary anatomical landmarks and to assist the surgeon in determining if any adjustments are necessary to the soft tissue envelope of the knee  114 . Even though the resections made to the femur  108  and the tibia  112  have been made without the assistance of the surgical navigation system  100 , the surgical navigation system  110  can assist the surgeon to properly balance the knee  114  using the chosen implants by assisting in making the appropriate releases to the soft tissue envelope surrounding the knee  114 .  
       FIG. 21  shows a further embodiment of the present invention. In this embodiment, a pin  370  has a proximal end (not shown) that includes a barb or other conventional connection device to affix the pin  370  to the distal portion  132  of the femur  108 . The pin  370  also has a distal end  372 . A docking device  374  is affixed to the distal end  372 . The docking device  374  is similar to the docking device  150 . A tracking device  376  similar to the tracking device  146  can be inserted into the docking device  374 . Once the pin  370  with the attached tracking device  376  is affixed to the femur  108 , the anatomical profile of the femur can be determined in a manner similar to that described above. The pin  370  is inserted into the femur  108  such that when cuts are made to the femur  108  during a later surgical procedure, the part of the distal portion  132  to which the pin  370  has been attached will have been removed.  
     INDUSTRIAL APPLICABILITY  
      The method and system will assist in the performance of orthopedic surgeries, such as TKA surgery and UKA surgery, with a minimal number of added invasions to the bone.  
      Numerous modifications to the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention and to teach the best mode of carrying out same. The exclusive rights to all modifications which come within the scope of the appended claims are reserved. I/We claim: