Apparatus and method for use during surgery

• US 5,514,143 A
• Filed: 11/27/1991
• Issued: 05/07/1996
• Est. Priority Date: 11/27/1991
• Status: Expired due to Term

• Current Assignee: Bonutti Skeletal Innovations LLC (Acacia Research Corporation)
• Original Assignee: Apogee Medical Products, Inc.
• Inventors: Bonutti, Peter M., Zitzmann, Gary E.
• Primary Examiner(s): Brown, Michael A.
• Application Number:
  US07/799,560
• Time in Patent Office: 1,623 Days
• Field of Search: 66/86, 66/87, 66/88, 66/79, 66/82, 623/18, 623/39, 128/882
• US Class Current: 606/86.00R
• CPC Class Codes: A61B 17/154 for preparing bone for knee prosthesis
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia

Abstract

An improved apparatus provided to position the femur and tibia of a leg relative to each other during surgery includes a femoral section which is fixedly mounted on the femur and a tibial section which is fixedly mounted on the tibia. The femoral and tibial sections are movable relative to each other during bending of the leg. An index assembly is provided to interconnect the femoral and tibial sections when the femur and tibia are in any one of a plurality of predetermined orientations relative to each other. A pair of cams and cam followers are provided on opposite sides of the leg to support and guide movement of the femur and tibia relative to each other during bending of the leg. The cams have surfaces with configurations which are a function of the relative movement between the femur and tibia during bending of the leg. The cams and cam followers can be used to effect distraction of the knee joint and to maintain the extent of distraction of the knee joint constant during bending of the leg. The medial and lateral portions of the knee joint may have different extents of distraction.

Claims

1. Apparatus for use in surgery on a leg having a femur and a tibia and a knee joint with a knee axis of rotation, said apparatus comprising:

a femoral portion and means for securing said femoral portion to the femur, said femoral portion being secured to the femur at a first location spaced from the knee axis of rotation;

a tibial portion and means for securing said tibial portion to the tibia;

connection means on said tibial portion and said femoral portion for electively connecting said tibial portion to said femoral portion for relative movement about an apparatus axis of rotation, said connection means being movable between (a) a locking condition fixing said tibial portion and said femoral portion in a selected one of a plurality of predetermined rotational positions within the range of motion of the knee joint and thus blocking movement of the knee joint and (b) a release condition allowing relative movement of said tibial and femoral portions and thus allowing movement of the knee joint through its range of motion, said connection means comprises means for fixing the distance between said first location and the knee axis of rotation at different values when corresponding to different ones of said plurality of predetermined rotational positions;

said means for securing said femoral portion to the femur comprising means for securing said femoral portion to the femur comprising means for securing said femoral portion to the femur at a location spaced from the apparatus axis of rotation; and

a cam having a cam surface with a varying-radius profile on one of said femoral and tibial portions and a cam follower on the other one of said femoral and tibia portions, said cam follower being engageable with said cam surface during movement of the knee joint through its range of motion.

2. An apparatus as set forth in claim 1 further including a cam surface connected with one of said first and second sections and a follower connected with another of said first and second sections and engageable with said cam surface during flexion or extension of the leg, said cam surface having a configuration which is a function of the relative movement between the femur and tibia during flexion or extension of the leg.

3. An apparatus as set forth in claim 1 wherein said means for mounting said second section on the tibia includes means for fixedly securing the second section to the tibia at a mounting location, said second section and mounting location being movable relative to said first section along a longitudinal axis of the tibia during flexion or extension of the leg.

4. An apparatus as set forth in claim 1 wherein said index means includes adjustable means connected with one of said first and second sections for defining a plurality of index locations, said apparatus further including means for use in positioning said adjustable means relative to said one of said first and second sections to locate said plurality of index locations relative to said one of said first and second sections.

5. An apparatus as set forth in claim 4 wherein said means for positioning said adjustable means relative to said one of said first and second sections includes retainer means operable between a retaining condition holding said adjustable means against movement relative to said one of said first and second sections and a release condition enabling said adjustable means to move relative to said one of said first and second sections with at least two degrees of freedom of movement.

6. An apparatus as set forth in claim 4 wherein said adjustable means includes a cam surface and a follower, at least one of said cam surface and follower being adjustable relative to said one of said first and second sections.

7. An apparatus as set forth in claim 1 wherein said means for mounting said first section on the femur includes means for engaging a first side of the femur at a plurality of locations spaced apart in an axial direction along the first side of the femur and means for engaging a second side of the femur at a plurality of locations spaced apart in an axial direction along the second side of the femur, said means for mounting said second section on the tibia includes means for engaging a first side of the tibia at a plurality of locations spaced apart in an axial direction along a first side of the tibia and means for engaging a second side of the tibia at a plurality of locations spaced apart in an axial direction along the second side of the tibia.

8. An apparatus as set forth in claim 1 wherein said index means includes a plurality of index locations connected with one of said first and second sections and disposed in a noncircular arcuate array and means connected with the other of said first and second sections for engaging each of the index locations in turn.

9. An apparatus as set forth in claim 1 wherein said index means includes a first plurality of index locations disposed adjacent to a first side of the leg, each index location of said first plurality of index locations corresponding to a different orientation of the femur and tibia relative to each other, a second plurality of index locations disposed adjacent to a second side of the leg opposite from the first side of the leg, each index location of said second plurality of index locations corresponding to an orientation of the femur and tibia which is the same as an index location of the first plurality of index locations, first retainer means for engaging each of the index locations in the first plurality of index locations in turn, and second retainer means for engaging an index location in the second plurality of index locations which corresponds to an orientation of the femur and tibia which is the same as an index location engaged by said first retainer means.

10. An apparatus as set forth in claim 1 wherein said index means includes a plurality of spaced apart openings connected with one of said first and second sections and means for engaging each of said openings in turn connected with another of said first and second sections.

11. An apparatus as set forth in claim 1 further including means for effecting distraction of a knee joint interconnecting the femur and tibia, said means for effecting distraction including means for separating end portions of the femur and tibia and for maintaining the extent of separation of the end portions of the femur and tibia constant during flexion or extension of the leg.

12. An apparatus as set forth in claim 1 further including a first cam surface disposed adjacent to a first side of the leg, said first cam surface having a configuration which is a function of the configuration of at least a portion of an end portion of one of the femur and tibia, a second cam surface disposed adjacent to a second side of the leg opposite from the first side of the leg, said second cam surface having a configuration which is a function of the configuration of at least a portion of an end portion of one of the femur and tibia, a first cam follower disposed adjacent to the first side of the leg and engageable with the first cam surface during flexion or extension of the leg, and a second cam follower disposed adjacent to the second side of the leg and engageable with the second cam surface during flexion or extension of the leg.

13. An apparatus as set forth in claim 12 wherein said index means includes a first plurality of index locations connected with said first cam surface, each index location of said first plurality of index locations corresponding to a different orientation of the femur and tibia relative to each other, a second plurality of index locations connected with said second cam surface, each index location of said second plurality of index locations corresponding to an orientation of the femur and tibia which is the same as an index location of the first plurality of index locations, first retainer means for engaging each of the index locations in said first plurality of index locations to retain said first cam surface and said first cam follower against relative movement, and second retainer means for engaging an index location in said second plurality of index locations which corresponds to an index location engaged by said second retainer means to retain said second cam surface and second cam follower against relative movement.

14. An apparatus as set forth in claim 12 further including means for adjusting the position of said first and second cam surfaces relative to each other to effect distraction of one portion of a knee joint interconnecting the femur and tibia to a greater extent than another portion of the knee joint.

15. An apparatus as set forth in claim 12 further including means for adjusting the position of said first and second cam followers relative to each other to effect distraction of one portion of a knee joint interconnecting the femur and tibia to a greater extent than another portion of the knee joint.

86. Apparatus as defined in claim 1 wherein said means for securing said tibial portion to the tibia comprises means for securing said tibial portion to the tibia at a location spaced from the apparatus axis of rotation.

16. An apparatus for use in positioning the femur and tibia of a leg relative to each other during surgery, said apparatus comprising a first section, means for connecting said first section with the femur, a second section, means for connecting said second section with the tibia, a first cam surface connected with a first one of said first and second sections and disposed adjacent to a first side of the leg, a second cam surface connected with the first one of said first and second sections and disposed adjacent to a second side of the leg, said first and second cam surfaces having configurations which are a function of the relative movement between the femur and tibia during flexion or extension of the leg, a first follower connected with a second one of said first and second sections, and a second follower connected with said second one of said first and second sections, said first follower being disposed in engagement with said first cam surface during flexion or extension of the leg and said second follower being disposed in engagement with said second cam surface during flexion or extension of the leg, said first follower and said first cam surface being movable relative to each other during flexion or extension of the leg, said second follower and said second cam surface being movable relative to each other during flexion or extension of the leg.

17. An apparatus as set forth in claim 16 further including first means for adjusting the position of at least one of said first cam surface and said first follower relative to said first and second sections and second means for adjusting the position of at least one of said second cam surface and said second follower relative to said first and second sections.

18. An apparatus as set forth in claim 16 further including first surface means connected with said first cam surface for defining a first plurality of openings, first retainer means connected with said first follower for engaging each of the openings in said first plurality of openings in turn, second surface means connected with said second cam surface for defining a second plurality of openings, and second retainer means connected with said second follower for engaging each of the openings in said second plurality of openings in turn.

19. An apparatus as set forth in claim 16 wherein said first one of said first and second sections includes a base, said apparatus further including means for enabling said first cam surface to move relative to said base along a first axis and along a second axis which extends perpendicular to said first axis, and means for enabling said second cam surface to move relative to said base along a third axis which extends parallel to the first axis and along a fourth axis which extends parallel to the second axis.

20. An apparatus as set forth in claim 19 wherein said second one of said first and second sections includes second base, said apparatus further including means for enabling said first follower to move relative to said second base along a fifth axis and along a sixth axis which extends perpendicular to the fifth axis, and means for enabling said second follower to move relative to said second base along a seventh axis which extends parallel to the fifth axis and along an eighth axis which extends parallel to the sixth axis.

21. An apparatus as set forth in claim 16 wherein said means for connecting said second section with the tibia includes a locating member having a generally V-shaped cross sectional configuration, said locating member cooperating with the tibia to center the locating member relative to the tibia.

22. An apparatus as set forth in claim 16 wherein said means for connecting said first section with the tibia includes a first connector member which engages the tibia, said means for connecting said second section with the femur including a second connector member which engages the femur, said first and second connector members being spaced apart by a first distance as measured along longitudinal axes of the femur and tibia when the leg is extended, said first and second connector members being spaced apart by a second distance which is greater than the first distance, as measured along the longitudinal axes of the femur and tibia when the leg is flexed at an angle of 90°

.

23. An apparatus as set forth in claim 16 further including means for effecting distraction of a knee joint interconnecting the femur and tibia, said means for effecting distraction including means for changing the positions of said first and second followers relative to said second one of said first and second sections.

24. An apparatus as set forth in claim 16 wherein said means for connecting said first section with the femur includes means for mounting said first section on the femur, said means for connecting said second section with the tibia includes means for mounting said second section on the tibia.

25. An apparatus as set forth in claim 16 further including index means for retaining said first and second sections in any one of a plurality of predetermined orientations relative to each other to retain the femur and tibia in any one of a plurality of orientations relative to each other during surgery.

26. An apparatus for use in positioning the femur and tibia of a leg relative to each other during surgery, said apparatus comprising a first section, means for connecting said first section with the femur, a second section, means for connecting said second section with the tibia, first means for defining a first plurality of index locations disposed in a first noncircular arcuate array having a configuration which is a function of the relative movement between the femur and tibia during bending of the leg, said first means being disposed adjacent to a first side of the leg and being connected with a first one of said first and second sections, each index location of said first plurality of index locations corresponding to a different one of a plurality of predetermined orientations of the femur and tibia relative to each other, second means for defining a second plurality of index locations disposed in a second noncircular arcuate array having a configuration which is a function of the relative movement between the femur and tibia during bending of the leg, said second means being disposed adjacent to a second side of the leg and being connected with the first one of said first and second sections, each index location of said second plurality of index locations corresponding to a different one of the plurality of predetermined orientations of the femur and tibia relative to each other, first retainer means disposed adjacent to the first side of the leg for engaging each of the index locations in said first plurality of index locations in turn, said first retainer means being connected with a second one of said first and second sections, and second retainer means disposed adjacent to the second side of the leg for engaging an index location in said second plurality of index locations which corresponds to the same orientation of the femur and tibia as an index location engaged by said first retainer means, said first and second means and said first and second retainer means cooperating with said first and second sections to retain the femur and tibia in each of the predetermined orientations in turn.

27. An apparatus as set forth in claim 26 wherein said means for connecting said first section with the femur includes a plurality of members which engage the femur at a plurality of locations space apart along a longitudinal axis of the femur, said means for connecting said second section with the tibia including a plurality of members which engage the tibia at a plurality of locations spaced apart along a longitudinal axis of the tibia.

28. An apparatus as set forth in claim 27 wherein said first and second sections are movable relative to each other in such a manner as to vary a distance measured along the longitudinal axes of the femur and tibia and extending between said members which engage the femur and said members which engage the tibia during flexion or extension of the leg.

29. An apparatus as set forth in claim 26 wherein a distance between a transverse axis of a knee joint interconnecting femur and tibia and each index location of said first plurality of index locations is the same when each index location is engaged by said first retainer means and a distance between the transverse axis of the knee joint and each index location of said second plurality of index locations is the same when each index location is engaged by said second retainer means.

30. An apparatus as set forth in claim 26 further including means for adjusting the location of said first plurality of index locations relative to the first one of said first and second sections along a first axis and along a second axis which extends perpendicular to the first axis and means for adjusting the location of said second plurality of index locations relative to the first one of said first and second sections along a third axis and along a fourth axis which extends perpendicular to the third axis.

31. An apparatus as set forth in claim 26 wherein said means for connecting said first section with the femur includes means for mounting said first section on the femur for movement therewith, said means for connecting said second section with the tibia including means for mounting said second section on the tibia for movement therewith.

32. An apparatus as set forth in claim 26 wherein said first means for defining a first plurality of index locations includes means for defining a plurality of index locations which are spaced unequal distances apart in the first noncircular arcuate array, said second means for defining a second plurality of index locations includes means for defining a plurality of index locations which are spaced unequal distances apart in the second noncircular arcuate array.

33. An apparatus as set forth in claim 26 further including means for effecting distraction of a knee joint interconnecting the femur and tibia, said means for effecting distraction of the knee joint including means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation between end portions of the femur and tibia constant during flexion or extension of the leg.

34. An apparatus as set forth in claim 26 further including means for adjusting the positions of said first and second pluralities of index locations relative to each other to enable one portion of a knee joint interconnecting the femur and tibia to be distracted a greater extent than another portion of the knee joint.

35. An apparatus as set forth in claim 26 further including a first cam surface connected with the first one of said first and second sections in a fixed spatial relationship with said first plurality of index locations, a second cam surface connected with the first one of said first and second sections in a fixed spatial relationship with said second plurality of index locations, a first follower connected with the second one of said first and second sections, and a second follower connected with the second one of said first and second sections, said first follower being disposed in engagement with said first cam surface during flexion or extension of the leg and said second follower being disposed in engagement with said second cam surface during flexion or extension of the leg.

36. An apparatus as set forth in claim 35 wherein said first plurality of index locations, said first cam surface, said second plurality of index locations, and said second cam surface are all connected with said first section.

37. An apparatus for use in positioning the femur and tibia of a leg in a plurality of orientations relative to each other during surgery, said apparatus comprising a first section, means for connecting said first section with the femur, a second section, means for connecting said second section with the tibia, said first and second sections being movable relative to each other during flexion or extension of the leg to change the orientation of the femur and tibia relative to each other during surgery, and means for effecting distraction of a knee joint interconnecting the femur and tibia, said means for effecting distraction including means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation of end portions of the femur and tibia constant during flexion or extension of the leg to change the orientation of the femur and tibia relative to each other during surgery.

38. An apparatus as set forth in claim 37 wherein said means for moving end portions of the femur and tibia away from each other and maintaining the extent of separation of the end portions of the femur and tibia constant during flexion or extension of the leg includes means for moving medial and lateral portions of the end portions of the femur and tibia through different distances and for maintaining the extent of separation of the medial and lateral portions of the end portions of the femur and tibia constant during flexion or extension of the leg.

39. An apparatus as set forth in claim 37 wherein said means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation of the end portions of the femur and tibia constant during flexion or extension of the leg includes a first cam surface connected with a first one of the femur and tibia adjacent to a medial side of the knee joint, a second cam surface connected with said first one of the femur and tibia adjacent to a lateral side of the knee joint, a first cam follower connected with a second one of the femur and tibia adjacent to the medial side of the knee joint, and a second cam follower connected with said second one of the femur and tibia adjacent to the lateral side of the knee joint, said first cam surface and said first cam follower being disposed in engagement with each other throughout flexion or extension of the leg through at least a portion of its range of movement and said second cam surface and said second cam follower being disposed in engagement with each other throughout flexion or extension of the leg through at least a portion of its range of movement.

40. An apparatus as set forth in claim 39 wherein said first and second cam surfaces are adjustable relative to said first one of the femur and tibia and said first and second cam followers are adjustable relative to said second one of the femur and tibia to enable the medial and lateral portions of the femur and tibia to be moved away from each other through different distances.

41. An apparatus as set forth in claim 37 further including index means for retaining said first and second sections in any one of a plurality of predetermined orientations relative to each other to retain the femur and tibia in any one of a plurality of orientations relative to each other during surgery.

42. An apparatus as set forth in claim 37 wherein said means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation of the end portions of the femur and tibia constant during flexion or extension of the leg includes a cam surface connected with one of said first and second sections and a follower connected with the another of said first and second sections, said cam surface having a configuration which is a function of the relative movement between the femur and tibia during flexion or extension of the leg.

43. An apparatus as set forth in claim 37 wherein said means for connecting said first section with the femur includes means for connecting said first section with the femur at a plurality of locations which are spaced apart along a longitudinal axis of the femur, said means for connecting said second section with the tibia includes means for connecting said second section with the tibia at a plurality of locations which are spaced apart along a longitudinal axis of the femur, said means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation of the end portions of the femur and tibia constant during flexion or extension of the leg including means for enabling said second section to move relative to said first section along a longitudinal axis of the tibia during flexion or extension of the leg.

44. An apparatus as set forth in claim 37 further including a plurality of index locations connected with a first one of said first and second sections and disposed in a noncircular array and means connected with a second one of said first and second sections for engaging each of said index locations in turn to locate the femur and tibia relative to each other.

45. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of aligning a cam with a first one of the femur and tibia, fixedly connecting the cam with the first one of the femur and tibia, aligning a follower with a second one of the femur and tibia, fixedly connecting the follower with the second one of the femur and tibia, thereafter, bending the leg to change the position of the femur and tibia relative to each other, and maintaining the cam and follower in engagement during said step of bending the leg.

46. A method as set forth in claim 45 further including the step of maintaining the femur and tibia in a first position relative to each other by retaining the cam and follower against movement relative to each other prior to performance of said step of bending the leg, after performance of said step of maintaining the femur and tibia in the first position relative to each other, performing said step of bending the leg, thereafter, maintaining the femur and tibia in a second position relative to each other by retaining the cam and follower against movement relative to each other.

47. A method as set forth in claim 45 further including the step of distracting a knee interconnecting the femur and tibia prior to performance of said step of bending the leg, and maintaining the extent of distraction of the knee constant during said step of bending the leg.

48. A method as set forth in claim 47 wherein said step of distracting the knee includes separating medial and lateral portions of end portions of the femur and tibia to different extents, said step of maintaining the extent of distraction of the knee constant during said step of bending the leg includes maintaining the different extents of separation of the medial and lateral portions of the end portions of femur and tibia constant at the different extents of distraction.

49. A method as set forth in claim 45 further including the step of fixedly connecting a first mounting section with the first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, said step of aligning a cam with the first one of the femur and tibia includes the step of fixedly securing the cam with the first mounting section after fixedly connecting the first mounting section with the first one of the femur and tibia, said method further including the step of fixedly connecting a second mounting section with the second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia,said step of aligning a follower with the second one of the femur and tibia includes the step of fixedly securing the follower with the second mounting section after fixedly connecting the second mounting section with the second one of the femur and tibia.

50. A method as set forth in claim 45 wherein said step of aligning a follower with a second one of the femur and tibia is performed prior to performance of said step of aligning a cam with a first one of the femur and tibia.

51. A method as set forth in claim 45 wherein said steps of aligning a cam with a first one of the femur and tibia and aligning a follower with a second one of the femur and tibia include locating a transverse axis of a knee interconnecting the femur and tibia, positioning the cam relative to the transverse axis of the knee, and positioning the follower relative to the transverse axis of the knee.

52. A method as set forth in claim 51 wherein said step of positioning the cam relative to the transverse axis of the knee includes moving the cam in a plane which extends generally perpendicular to the transverse axis of the knee, said step of positioning the follower relative to the transverse axis of the knee includes moving the follower in a plane which extends generally perpendicular to the transverse axis of the knee.

53. A method as set forth in claim 45 wherein said step of aligning the cam with a first one of the femur and tibia includes moving the leg and moving the cam relative to the first one of the femur and tibia during performance of said step of bending the leg.

54. A method as set forth in claim 45 further including the step of connecting a first mounting section with the first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, and connecting a second mounting section with the second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, said step of connecting a first mounting section with a first one of the femur and tibia being performed with the first mounting section spaced apart from the second mounting section and with the cam and follower spaced apart from each other.

55. A method as set forth in claim 54 wherein said steps of aligning the cam with the first one of the femur and tibia and aligning the follower with the second one of the femur and tibia includes moving the cam and follower into abutting engagement.

56. A method as set forth in claim 54 wherein said step of connecting the second mounting section with the second one of the femur and tibia includes engaging the tibial portion of the leg with a positioning member having a generally V-shaped cross sectional configuration to locate the second mounting section relative to the tibia.

57. A method as set forth in claim 54 wherein said step of connecting a first mounting section with the first one of the femur and tibia is performed with the cam disposed on the first mounting section, said steps of connecting a second mounting section with a second one of the femur and tibia is performed with the follower disposed on the second mounting section, said method further including the step of moving the cam and follower relative to the first and second mounting sections after performing said steps of connecting the first mounting section with the first one of the femur and tibia and connecting the second mounting section with the second one of the femur and tibia.

58. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of connecting a first mounting section with a first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, connecting a second mounting section with a second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, thereafter, bending the leg to a first predetermined position, said step of bending the leg to a first predetermined position including effecting relative movement between the first and second mounting sections, interconnecting the first and second sections to retain the leg in the first predetermined position, making a first cut on the femur while first and second mounting sections are interconnected with the leg in the first predetermined position, disconnecting the first and second mounting sections to release the leg for movement from the first predetermined position, thereafter bending the leg from the first predetermined position to a second predetermined position, said step of bending the leg to a second predetermined position including effecting relative movement between the first and second mounting sections, interconnecting the first and second mounting sections to retain the leg in the second predetermined position, and making a second cut on the femur while the first and second mounting sections are interconnected with the leg in the second predetermined position.

59. A method as set forth in claim 58 wherein said step of bending the leg from the first predetermined position to the second predetermined position includes bending the leg through a first angle, said step of making a first cut on the femur includes making the first cut with at least a portion of the first cut disposed in a first plane, said step of making a second cut including making the second cut with at least a portion of the second cut in a second plane which extends at the first angle relative to the first plane.

60. A method as set forth in claim 58 wherein said step of bending the leg from the first predetermined position to the second predetermined position includes varying a distance measured along the longitudinal axes of the femur and tibia and extending between the first and second sections.

61. A method as set forth in claim 58 further including the steps of distracting a knee joint interconnecting the femur and tibia and maintaining the extent of distraction of the knee joint constant during performance of said step of bending the leg from the first predetermined position to the second predetermined position.

62. A method as set forth in claim 58 further including the step of maintaining a cam connected with the first mounting section in engagement with a follower connected with the second mounting section during performance of said step of bending the leg from the first predetermined position to the second predetermined position.

63. A method as set forth in claim 58 wherein said step of connecting a first mounting section with a first one of the femur and tibia is performed with the second mounting section disconnected from the first mounting section.

64. A method of positioning a femur and tibia of a leg in a plurality of positions relative to each other during surgery, said method comprising the steps of distracting a knee joint interconnecting the femur and tibia, thereafter, bending the leg at the knee joint from a first position to a second position by causing flexion or extension of the leg about the knee joint, and maintaining the extent of distraction of the knee joint constant during bending of the leg at the knee joint with flexion or extension of the leg about the knee joint.

65. A method as set forth in claim 64 wherein said step of distracting the knee joint includes separating end portions of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint including maintaining the separation of the end portions of the femur and tibia constant during bending of the leg.

66. A method as set forth in claim 64 wherein said step of distracting a knee joint includes separating the femur and tibia by a first distance at a first portion of the knee joint and separating the femur and tibia by a second distance at a second portion of the knee joint, said first distance being greater than said second distance, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint includes maintaining the first and second distances constant during bending of the knee joint.

67. A method as set forth in claim 64 wherein said step of distracting a knee joint includes moving one of a cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

68. A method as set forth in claim 64 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a follower with a second one of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint including transmitting force between a cam and cam follower during bending of the knee joint.

69. A method as set forth in claim 68 further including the step of maintaining the cam and cam follower in engagement during said step of bending the leg.

70. A method as set forth in claim 64 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a cam follower with a second one of the femur and tibia, said steps of aligning a cam with a first one of the femur and tibia and aligning a cam follower with a second one of the femur and tibia including moving one of the cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

71. A method as set forth in claim 64 further including the steps of positioning first and second cams adjacent to opposite sides of the knee, said step of positioning first and second cams adjacent to opposite sides of the knee including connecting a first mounting section with a first one of the femur and tibia, positioning first and second cam followers adjacent to opposite sides of the knee, said step of positioning first and second cam followers adjacent to opposite sides of the knee including connecting a second mounting section with a second one of the femur and tibia, said step of distracting the knee including transmitting force from the first and second cams to the first one of the femur and tibia through the first mounting section and transmitting force from the first and second cam followers to the second one of the femur and tibia through the second mounting section.

72. A method as set forth in claim 71 further including the step of maintaining the first cam and first cam follower in engagement during performance of said step of bending of the leg from the first position to the second position, and maintaining the second cam and second cam follower in engagement during bending of the leg from the first position to the second position.

73. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of aligning a cam with a first one of the femur and tibia, aligning a follower with a second one of the femur and tibia, thereafter, bending the leg to change the position of the femur and tibia relative to each other, maintaining the cam and follower in engagement during said step of bending the leg, fixedly connecting a first mounting section with the first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, said step of aligning a cam with the first one of the femur and tibia includes the step of fixedly securing the cam with the first mounting section after fixedly connecting the first mounting section with the first one of the femur and tibia, said method further including the step of fixedly connecting a second mounting section with the second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, said step of aligning a follower with the second one of the femur and tibia includes the step of fixedly securing the follower with the second mounting section after fixedly connecting the second mounting section with the second one of the femur and tibia, said step of bending the leg includes moving the first and second mounting sections relative to each other.

74. A method as set forth in claim 73 further including the step of maintaining the femur and tibia in a first position relative to each other by retaining the cam and follower against movement relative to each other prior to performance of said step of bending the leg, after performance of said step of maintaining the femur and tibia in the first position relative to each other, performing said step of bending the leg, thereafter, maintaining the femur and tibia in a second position relative to each other by retaining the cam and follower against movement relative to each other.

75. A method as set forth in claim 73 further including the step of distracting a knee interconnecting the femur and tibia prior to performance of said step of bending the leg, and maintaining the extent of distraction of the knee constant during said step of bending the leg.

76. A method as set forth in claim 75 wherein said step of distracting the knee includes separating medial and lateral portions of end portions of the femur and tibia to different extents, said step of maintaining the extent of distraction of the knee constant during said step of bending the leg includes maintaining the different extents of separation of the medial and lateral portions of the end portions of femur and tibia constant at the different extents of distraction.

77. A method as set forth in claim 73 wherein said step of aligning a follower with a second one of the femur and tibia is performed prior to performance of said step of aligning a cam with a first one of the femur and tibia.

78. A method as set forth in claim 73 wherein said steps of aligning a cam with a first one of the femur and tibia and aligning a follower with a second one of the femur and tibia include locating a transverse axis of a knee interconnecting the femur and tibia, positioning the cam relative to the transverse axis of the knee, and positioning the follower relative to the transverse axis of the knee.

79. A method as set forth in claim 78 wherein said step of positioning the cam relative to the transverse axis of the knee includes moving the cam in a plane which extends generally perpendicular to the transverse axis of the knee, said step of positioning the follower relative to the transverse axis of the knee includes moving the follower in a plane which extends generally perpendicular to the transverse axis of the knee.

80. A method as set forth in claim 73 wherein said step of aligning the cam with a first one of the femur and tibia includes moving the leg and moving the cam relative to the first one of the femur and tibia during performance of said step of bending the leg.

81. A method as set forth in claim 73 wherein said step of connecting a first mounting section with a first one of the femur and tibia being performed with the first mounting section spaced apart from the second mounting section and with the cam and follower spaced apart from each other.

82. A method as set forth in claim 81 wherein said steps of aligning the cam with the first one of the femur and tibia and aligning the follower with the second one of the femur and tibia includes moving the cam and follower into abutting engagement.

83. A method as set forth in claim 81 wherein said step of connecting the second mounting section with the second one of the femur and tibia includes engaging the tibial portion of the leg with a positioning member having a generally V-shaped cross sectional configuration to locate the second mounting section relative to the tibia.

84. A method as set forth in claim 73 wherein said step of connecting a first mounting section with the first one of the femur and tibia is performed with the cam disposed on the first mounting section, said step of connecting a second mounting section with a second one of the femur and tibia is performed with the follower disposed on the second mounting section, said method further including the step of moving the cam and follower relative to the first and second mounting sections after performing said steps of connecting the first mounting section with the first one of the femur and tibia and connecting the second mounting section with the second one of the femur and tibia.

85. A method as set forth in claim 73 further including the steps of positioning the femur and tibia in a first orientation relative to each other, making a first cut on the femur with at least a portion of the first cut in a first plane, bending the leg through a first angle to change the angular orientation of the femur and tibia and to position the femur and tibia in a second orientation relative to each other, thereafter, making a second cut on the femur with at least a portion of the second cut in a second plane which extends at the first angle relative to the first plane, bending the leg through a second angle to change the angular orientation of the femur and tibia and to position the femur and tibia in a third orientation relative to each other, and, thereafter, making a third cut on the femur with at least a portion of the third cut in a third plane which extends at the second angle relative to the second plane.

87. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of aligning a cam with a first one of the femur and tibia, aligning a follower with a second one of the femur and tibia, thereafter, positioning the femur and tibia in a first orientation relative to each other, making a first cut on the femur with at least a portion of the first cut in a first plane, bending the leg through a first angle to change the angular orientation of the femur and tibia and to position the femur and tibia in a second orientation relative to each other, thereafter, making a second cut on the femur with at least a portion of the second cut in a second plane which extends at the first angle relative to the first plane, bending the leg through a second angle to change the angular orientation of the femur and tibia and to position the femur and tibia in a third orientation relative to each other, thereafter, making a third cut on the femur with at least a portion of the third cut in a third plane which extends at the second angle relative to the second plane, and maintaining the cam and follower in engagement during said steps of bending the leg.

88. A method as set forth in claim 87 further including the step of sequentially maintaining the femur and tibia in each of the first, second and third orientations relative to each other by retaining the cam and follower against movement relative to each other.

89. A method as set forth in claim 87 further including the step of distracting a knee interconnecting the femur and tibia prior to performance of said steps of making first, second and third cuts on the femur and maintaining the extent of distraction of the knee constant during said steps of bending the leg.

90. A method as set forth in claim 89 wherein said step of distracting the knee includes separating medial and lateral portions of end portions of the femur and tibia to different extents, said step of maintaining the extent of distraction of the knee constant during said steps of bending the leg includes maintaining the different extents of separation of the medial and lateral portions of the end portions of femur and tibia constant at the different extents of distraction.

91. A method as set forth in claim 87 further including the step of fixedly connecting a first mounting section with the first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, said step of aligning a cam with the first one of the femur and tibia includes the step of fixedly securing the cam with the first mounting section after fixedly connecting the first mounting section with the first one of the femur and tibia, said method further including the step of fixedly connecting a second mounting section with the second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, said step of aligning a follower with the second one of the femur and tibia includes the step of fixedly securing the follower with the second mounting section after fixedly connecting the second mounting section with the second one of the femur and tibia.

92. A method as set forth in claim 87 wherein said step of aligning a follower with a second one of the femur and tibia is performed prior to performance of said step of aligning a cam with a first one of the femur and tibia.

93. A method as set forth in claim 87 wherein said steps of aligning a cam with a first one of the femur and tibia and aligning a follower with a second one of the femur and tibia include locating a transverse axis of a knee interconnecting the femur and tibia, positioning the cam relative to the transverse axis of the knee, and positioning the follower relative to the transverse axis of the knee.

94. A method as set forth in claim 93 wherein said step of positioning the cam relative to the transverse axis of the knee includes moving the cam in a plane which extends generally perpendicular to the transverse axis of the knee, said step of positioning the follower relative to the transverse axis of the knee includes moving the follower in a plane which extends generally perpendicular to the transverse axis of the knee.

95. A method as set forth in claim 87 wherein said step of aligning the cam with a first one of the femur and tibia includes moving the leg and moving the cam relative to the first one of the femur and tibia.

96. A method as set forth in claim 87 further including the step of connecting a first mounting section with the first one of the femur and tibia, and connecting a second mounting section with the second one of the femur and tibia.

97. A method as set forth in claim 96 wherein said steps of aligning the cam with the first one of the femur and tibia and aligning the follower with the second one of the femur and tibia includes moving the cam and follower into abutting engagement after performing said step of connecting a first mounting section with the first one of the femur and tibia and after performing said step of connecting a second mounting section with the second one of the femur and tibia.

98. A method as set forth in claim 96 wherein said step of connecting the second mounting section with the second one of the femur and tibia includes engaging the tibial portion of the leg with a positioning member having a generally V-shaped cross sectional configuration to locate the second mounting section relative to the tibia.

99. A method as set forth in claim 96 wherein said step of connecting a first mounting section with the first one of the femur and tibia is performed with the cam disposed on the first mounting section, said step of connecting a second mounting section with a second one of the femur and tibia is performed with the follower disposed on the second mounting section, said method further including the step of moving the cam and follower relative to the first and second mounting sections after performing said steps of connecting the first mounting section with the first one of the femur and tibia and connecting the second mounting section with the second one of the femur and tibia.

100. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of distracting a knee joint interconnecting the femur and tibia, thereafter, positioning the leg in the first position with the femur and tibia in a first orientation relative to each other, making a first cut on the femur with at least a portion of the first cut in a first plane while the leg is in the first position, bending the leg from a first position to a second position, maintaining the extent of distraction of the knee joint constant during bending of the leg from the first position to the second position, said step of bending the leg from a first position to a second position including changing the angular orientation of the femur and tibia through a first angle and to position the femur and tibia in a second orientation relative to each other, thereafter, making a second cut on the femur with at least a portion of the second cut in a second plane which extends at the first angle relative to the first plane, bending the leg from the second position to a third position to change the angular orientation of the femur and tibia through a second angle and to position the femur and tibia in a third orientation relative to each other, maintaining the extent of distraction of the knee joint constant during bending of the leg from the second position to the third position, and, thereafter, making a third cut on the femur with at least a portion of the third cut in a third plane which extends at the second angle relative to the second plane.

101. A method as set forth in claim 100 wherein said step of distracting the knee joint includes separating end portions of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint including maintaining the separation of the end portions of the femur and tibia constant during bending of the leg.

102. A method as set forth in claim 100 wherein said step of distracting a knee joint includes separating the femur and tibia by a first distance at a first portion of the knee joint and separating the femur and tibia by a second distance at a second portion of the knee joint, said first distance being greater than said second distance, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint includes maintaining the first and second distances constant during bending of the knee joint.

103. A method as set forth in claim 100 wherein said step of distracting a knee joint includes moving one of a cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

104. A method as set forth in claim 100 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a follower with a second one of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the knee joint including transmitting force between the cam and the cam follower during bending of the knee joint.

105. A method as set forth in claim 104 further including the step of maintaining the cam and cam follower in engagement during said step of bending the leg.

106. A method as set forth in claim 100 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a cam follower with a second one of the femur and tibia, said steps of aligning a cam with a first one of the femur and tibia and aligning a cam follower with a second one of the femur and tibia including moving one of the cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

107. A method as set forth in claim 100 further including the steps of positioning first and second cams adjacent to opposite sides of the knee, said step of positioning first and second cams adjacent to opposite sides of the knee including connecting a first mounting section with a first one of the femur and tibia, positioning first and second cam followers adjacent to opposite sides of the knee, said step of positioning first and second cam followers adjacent to opposite sides of the knee including connecting a second mounting section with a second one of the femur and tibia, said step of distracting the knee including transmitting force between the first and second cams and the first and second cam followers.

108. A method as set forth in claim 107 further including the step of maintaining the first cam and first cam follower in engagement during performance of said step of bending of the leg from the first position to the second position, and maintaining the second cam and second cam follower in engagement during bending of the leg from the first position to the second position.

109. A method as set forth in claim 100 further including the steps of connecting a first mounting section with a first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, connecting a second mounting section with a second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, thereafter, interconnecting the first and second mounting sections to retain the leg in the first position, disconnecting the first and second mounting sections to release the leg for movement from the first position after making the first cut, said step of bending the leg to a second position including effecting relative movement between the first and second mounting sections, and interconnecting the first and second mounting sections to retain the leg in the second position.

110. A method as set forth in claim 109 wherein said step of connecting a first mounting section with a first one of the femur and tibia is performed with the second mounting section disconnected from the first mounting section.

111. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of connecting a first mounting section with a first one of the femur and tibia at a plurality of locations along a longitudinal axis of the first one of the femur and tibia, connecting a second mounting section with a second one of the femur and tibia at a plurality of locations along a longitudinal axis of the second one of the femur and tibia, distracting a knee joint interconnecting the femur and tibia, thereafter, positioning the leg in a first position, said step of positioning the leg in a first position including effecting relative movement between the first and second mounting sections, interconnecting the first and second mounting sections to retain the leg in the first position, making a first cut on the femur while first and second mounting sections are interconnected with the leg in the first position, disconnecting the first and second mounting sections to release the leg for movement from the first position, thereafter, bending the leg from a first position to a second position, said step of bending the leg to a second position including effecting relative movement between the first and second mounting sections, interconnecting the first and second mounting sections to retain the leg in the second position, and making a second cut on the femur while the first and second mounting sections are interconnected with the leg in the second predetermined position, and maintaining the extent of distraction of the knee joint constant during bending of the leg.

112. A method as set forth in claim 111 wherein said step of connecting a first mounting section with a first one of the femur and tibia is performed with the second mounting section disconnected from the first mounting section.

113. A method as set forth in claim 111 wherein said step of distracting the knee joint includes separating end portions of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the leg including maintaining the separation of the end portions of the femur and tibia constant during bending of the leg.

114. A method as set forth in claim 111 wherein said step of distracting a knee joint includes separating the femur and tibia by a first distance at a first portion of the knee joint and separating the femur and tibia by a second distance at a second portion of the knee joint, said first distance being greater than said second distance, said step of maintaining the extent of distraction of the knee joint constant during bending of the leg includes maintaining the first and second distances constant during bending of the leg.

115. A method as set forth in claim 111 wherein said step of distracting a knee joint includes moving one of a cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

116. A method as set forth in claim 111 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a follower with a second one of the femur and tibia, said step of maintaining the extent of distraction of the knee joint constant during bending of the leg including transmitting force between the cam and the cam follower during bending of the leg.

117. A method as set forth in claim 116 further including the step of maintaining the cam and cam follower in engagement during said step of bending the leg.

118. A method as set forth in claim 111 further including the steps of aligning a cam with a first one of the femur and tibia, and aligning a cam follower with a second one of the femur and tibia, said steps of aligning a cam with a first one of the femur and tibia and aligning a cam follower with a second one of the femur and tibia including moving one of the cam and cam follower relative to one of the femur and tibia while maintaining the position of another one of the cam and cam follower constant relative to another one of the femur and tibia.

119. A method as set forth in claim 111 further including the steps of positioning first and second cams adjacent to opposite sides of the knee, positioning first and second cam followers adjacent to opposite sides of the knee, said step of distracting the knee including transmitting force from the first and second cams to the first one of the femur and tibia through the first mounting section and transmitting force from the first and second cam followers to the second one of the femur and tibia through the second mounting section.

120. A method as set forth in claim 119 further including the step of maintaining the first cam and first cam follower in engagement during performance of said step of bending of the leg from the first position to the second position, and maintaining the second cam and second cam follower in engagement during bending of the leg from the first position to the second position.

121. An apparatus for use in positioning the femur and tibia of a leg relative to each other during surgery, said apparatus comprising a first section, means for connecting said first section with the femur, a second section, means for connecting said second section with the tibia, first means for defining a first plurality of index locations disposed in a first array, said first means being disposed adjacent to a side of the leg and being connected with a first one of said first and second sections, each index location of said first plurality of index locations corresponding to a different one of a plurality of predetermined orientations of the femur and tibia relative to each other, means for adjusting the location of said first plurality of index locations relative to the first one of said first and second sections along a first axis and along a second axis which extends perpendicular to the first axis, and first retainer means disposed adjacent to the side of the leg for engaging each of the index locations in said first plurality of index locations in turn, said first retainer means being connected with a second one of said first and second sections.

122. An apparatus as set forth in claim 121 wherein said means for connecting said first section with the femur includes a plurality of members which engage the femur at a plurality of locations spaced apart along a longitudinal axis of the femur, said means for connecting said second section with the tibia including a plurality of members which engage the tibia at a plurality of locations spaced apart along a longitudinal axis of the tibia.

123. An apparatus as set forth in claim 121 wherein said first and second sections are movable relative to each other during flexion or extension of the leg to vary a distance measured along the longitudinal axes of the femur and tibia and extending between said means for connecting said first section with the femur and said means for connecting said second section with the tibia.

124. An apparatus as set forth in claim 121 wherein said first means for defining a first plurality of index locations includes means for defining a plurality of index locations which are spaced unequal distances apart in a noncircular arcuate array having a configuration which is a function of the relative movement between the femur and tibia during bending of the leg.

125. An apparatus as set forth in claim 121 further including means for effecting distraction of a knee joint interconnecting the femur and tibia, said means for effecting distraction of the knee joint including means for moving end portions of the femur and tibia away from each other and for maintaining the extent of separation between end portions of the femur and tibia constant during flexion or extension of the leg.

126. An apparatus as set forth in claim 121 further including means connected with said first and second sections for maintaining a distance separating end portions of the femur and tibia constant during flexion or extension of the leg during surgery.

127. An apparatus as set forth in claim 126 wherein said means for maintaining a distance separating end portions of the femur and tibia constant during flexion or extension of the leg includes means for effecting distraction of a knee joint interconnecting the femur and tibia.

128. A method of positioning a femur and tibia of a leg relative to each other during surgery, said method comprising the steps of connecting a first mounting section with a first one of the femur and tibia, connecting a second mounting section with a second one of the femur and tibia, moving a first cam connected with the first mounting section and a first follower connected with the second mounting section into engagement, said step of moving a first cam and first follower into engagement being performed with the first cam and first follower disposed adjacent to a first side of the leg, moving a second cam connected with the first mounting section and a second follower connected with the second mounting section into engagement, said step of moving a second cam and a second follower into engagement being performed with the second cam and second follower adjacent to a second side of the leg, thereafter, bending the leg, moving the first cam and first follower relative to each other while maintaining the first cam and first follower in engagement with each other during performance of said step of bending the leg, and moving the second cam and second follower relative to each other while maintaining the second cam and second follower in engagement with each other during performance of said step of bending the leg.

129. A method as set forth in claim 128 further including the steps of distracting a knee joint interconnecting the femur and tibia, thereafter, performing said step of bending the leg, and maintaining the extent of distraction of the knee joint constant during performance of said step of bending the leg.

130. A method as set forth in claim 129 wherein said step of maintaining the extent of distraction of the knee joint constant during bending the leg includes transmitting force between the first cam and first cam follower and transmitting force between the second cam and second cam follower during performance of said step of bending the leg.

131. An apparatus for use in positioning the femur and tibia of a leg relative to each other during surgery, said apparatus comprising a first section, means for connecting said first section with the femur, a second section, means for connecting said second section with the tibia, first cam means having a configuration which is a function of the configuration of at least a portion of an end portion of one of the femur and tibia, said first cam means being disposed adjacent to a first side of the leg and being connected with a first one of said first and second sections, first follower means for engaging said first cam means during bending of the leg, said first follower means being disposed adjacent to the first side of the leg and being connected with a second one of said first and second sections, second cam means having a configuration which is a function of the configuration of at least a portion of an end portion of one of the femur and tibia, said second cam means being disposed adjacent to a second side of the leg and being connected with the first one of said first and second sections, and second follower means for engaging said second cam means during bending of the leg, said second follower means being disposed adjacent to the second side of the leg and being connected with the second one of said first and second sections.

132. An apparatus as set forth in claim 131 wherein said means for connecting said first section with the femur includes a plurality of members which engage the femur at a plurality of locations spaced apart along a longitudinal axis of the femur, said means for connecting said second section with the tibia including a plurality of members which engage the tibia at a plurality of locations spaced apart along a longitudinal axis of the tibia.

133. An apparatus as set forth in claim 132 wherein said first and second sections are movable relative to each other in such a manner as to vary a distance measured along the longitudinal axes of the femur and tibia and extending between said members which engage the femur and said members which engage the tibia during flexion or extension of the leg.

134. An apparatus as set forth in claim 131 further including means for adjusting the location of said first cam means relative to the first one of said first and second sections along a first axis and along a second axis which extends perpendicular to the first axis and means for adjusting the location of said second cam means reactive to the first one of said first and second sections along a third axis and along a fourth axis which extends perpendicular to the third axis.

135. An apparatus as set forth in claim 131 wherein said means for connecting said first section with the femur includes means for mounting said first section on the femur for movement therewith, said means for connecting said second section with the tibia including means for mounting said second section on the tibia for movement therewith.

136. An apparatus as set forth in claim 131 wherein at least one of said first cam means and said first follower means and wherein at least one of said second cam means and said second follower means are adjustable to move portions of the femur and tibia away from each other.

137. An apparatus as set forth in claim 131 wherein at least one of said first cam means and first follower means is adjustable to move medial portions of the femur and tibia away from each other through a first distance and at least one of said second cam means and second follower means is adjustable to move lateral portions of the femur and tibia away from each other through a second distance which is different than the first distance.