Method of performing surgery

• US 20020029045A1
• Filed: 08/28/2001
• Published: 03/07/2002
• Est. Priority Date: 01/14/2000
• Status: Active Grant

• Current Assignee: Bonutti Skeletal Innovations LLC (Acacia Research Corporation)
• Original Assignee: The Bonutti 2003 Trust A
• Inventors: Bonutti, Peter M.
• Granted Patent: US 6,702,821 B2
• Time in Patent Office: Days
• US Class Current: 606/86
• CPC Class Codes: A61B 17/0401 Suture anchors, buttons or pledgets, i.e. means for attaching sutures to bone, cartilage or soft tissue; Instruments for applying or removing suture anchors A61B17/0642 takes precedence; fixation devices for tendons or ligaments A61F2/0811
• CPC Class Codes: A61B 17/0487 Suture clamps, clips or locks, e.g. for replacing suture knots; Instruments for applying or removing suture clamps, clips or locks suture anchors A61B17/0401; wound clamps or clips A61B17/08; ligaturing clamps or clips A61B17/122
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/80 Cortical plates , i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61B 2017/00004 (bio)absorbable, (bio)resorbable or resorptive
• CPC Class Codes: A61B 2017/0408 Rivets
• CPC Class Codes: A61B 2017/0409 Instruments for applying suture anchors
• CPC Class Codes: A61B 2017/0414 having a suture-receiving opening, e.g. lateral opening
• CPC Class Codes: A61B 2017/0496 for tensioning sutures
• CPC Class Codes: A61B 2017/0619 thermoplastic, e.g. for bonding, welding, fusing or cutting the suture by melting it
• CPC Class Codes: A61B 2017/867 with integral locking or clamping means
• CPC Class Codes: A61F 2/30734 Modular inserts, sleeves or augments, e.g. placed on proximal part of stem for fixation purposes or wedges for bridging a bone defect
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30736 Augments or augmentation pieces, e.g. wedges or blocks for bridging a bone defect
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0071 thermoplastic

Abstract

An improved method of performing surgery on a joint in a patient'"'"'s body, such as a knee, includes making an incision in a knee portion of one leg while a lower portion of the one leg is extending downward from an upper portion of the one leg and while a foot connected with the lower portion of the one leg is below a support surface on which the patient is disposed. The incision is relatively short, for example, between seven and thirteen centimeters. A patella may be offset from its normal position with an inner side of the patella facing inward during cutting of a bone with a cutting tool. During cutting of the bone, one or more guide members having opposite ends which are spaced apart by a distance less than the width of an implant may be utilized to guide movement of a cutting tool.

Claims

1. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the lower portion of the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and moving an implant into engagement with the one bone in the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

2. A method as set forth in claim 1 wherein said steps of making an incision in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

3. A method as set forth in claim 1 wherein said steps of making an incision in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with a hip connected with the one leg of the patient hyperflexed.

4. A method as set forth in claim 1 further including the steps of providing a guide member having opposite ends which are spaced apart by a distance which is less than a distance between lateral and medial epicondyles on a femur in the upper portion of the one leg of the patient, and positioning the guide member on the femur in the one leg of the patient with the opposite ends of the guide member substantially aligned with an axis through the lateral and medial epicondyles on the femur in the one leg of the patient, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool along a guide surface on the guide member and cutting bone on the lateral and medial condyles on the femur in the one leg of the patient.

5. A method as set forth in claim 1 wherein said step of making an incision in the knee portion of the one leg of the patient includes making an incision which has a length of between about seven and about thirteen centimeters when the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and the foot connected with the lower portion of the one leg of the patient is below the support surface.

6. A method as set forth in claim 1 including the steps of inserting at least one retractor into the incision in the knee portion of the one leg of the patient and holding back a margin of the incision with the retractor to increase exposure of the bone in the one leg of the patient through the incision while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and the foot connected with the lower portion of the one leg of the patient is below the support surface.

7. A method as set forth in claim 1 further including the steps of inserting a first retractor into the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, inserting a second retractor into the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and expanding an opening formed by the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface by separating opposite margins of the incision under the influence of force applied to opposite margins of the incision by the first and second retractors.

8. A method as set forth in claim 7 wherein said step of cutting the one bone in the one leg of the patient is at least partially performed while the opening formed by an incision in the knee portion of the one leg of the patient is expanded by the first and second retractors.

9. A method as set forth in claim 1 including the step of moving the lower portion of the one leg of the patient relative to the upper portion of the one leg along a path extending through lateral and medial surfaces of the lower portion of the one leg while the lower portion of the one leg is extending downward from the upper portion of the one leg and while the foot is below the support surface after having performed said step of cutting the one bone in the one leg of the patient.

10. A method as set forth in claim 9 wherein said step of moving the lower portion of the one leg relative to the upper portion of the one leg is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

11. A method as set forth in claim 1 further including the step of rotating the lower portion of the one leg of the patient about an axis extending along the lower portion of the one leg while the lower portion of the one leg is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface after having performed said step of cutting the one bone in the one leg of the patient.

12. A method as set forth in claim 11 wherein said step of rotating the lower portion of the one leg of the patient about an axis extending along the lower portion of the one leg is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

13. A method as set forth in claim 1 further including the step of transmitting force between an upper portion of a leg of a surgeon and the foot connected with the lower portion of the one leg of the patient to at least partially support the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

14. A method as set forth in claim 1 further including the step of maintaining a sterile field in a space between a surgeon and the patient by providing a drape system which extends between the surgeon and the patient with a portion of the drape system disposed beneath the foot connected with the one leg of the patient.

15. A method as set forth in claim 1 wherein said step of cutting the one bone in the one leg of the patient with the cutting tool includes cutting a distal end portion of a femur in the upper portion of the patient'"'"'s one leg to form a cut surface which extends at least part way across the distal end portion of the femur, cutting a proximal end portion of a tibia in the lower portion of the patient'"'"'s one leg to form a cut surface which extends at least part way across the proximal end portion of the tibia, and, thereafter, varying a space between the cut surface on the distal end portion of the femur and the cut surface on the proximal end portion of the tibia by moving the lower portion of the patient'"'"'s one leg relative to the upper portion of the patient'"'"'s one leg while the lower portion of the patient'"'"'s one leg is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

16. A method as set forth in claim 15 wherein said steps of cutting a distal end portion of the femur in the patient'"'"'s one leg and cutting a proximal end portion of the tibia in the patient'"'"'s one leg are performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

17. A method as set forth in claim 1 further including the step of distracting a joint in the knee portion of the one leg of the patient under the influence of force resulting from the weight of the lower portion of the one leg of the patient while the lower portion of the one leg is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

18. A method as set forth in claim 1 further including the step of hyperflexing the knee portion of the one leg of the patient while the lower portion of the one leg is extending downward from the upper portion of the leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface after having performed said step of cutting the one bone in the one leg of the patient.

19. A method as set forth in claim 1 further including the step of displacing a patella in the knee portion of the one leg from an initial position to an offset position in which the patella is offset from the initial position and in which the patella has an inner side which faces inward toward bones in the one leg, said step of cutting the one bone in the one leg of the patient being performed with the patella in the offset position and with an inner side of the patella facing toward a bone in the one leg.

20. A method as set forth in claim 19 wherein said step of cutting the one bone in the one leg of the patient with the cutting tool includes cutting across medial and lateral condyles of a femur in the one leg of the patient with the patella in the knee portion of the one leg in the offset position and with an inner side of the patella facing toward a bone in the one leg.

21. A method as set forth in claim 20 further including the step of everting the patella in the knee portion of the one leg of the patient to an orientation in which the inner side surface of the patella faces outward away from bones in the one leg.

22. A method as set forth in claim 1 further including the step of closing the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

23. A method as set forth in claim 1 further including the steps of positioning a guide member relative to the one bone in the one leg of the patient with a portion of the guide member overlying a portion of skin which encloses the one bone in the leg of the patient, and connecting the guide member with the one bone in the leg of the patient by moving a member through the skin which underlies the guide member into the one bone in the leg of the patient, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool along a guide surface on the guide member.

24. A method as set forth in claim 1 further including the step of moving at least a portion of a guide member through the incision, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool along a guide surface having a first length and forming a cut surface which is disposed on the one bone and which has a length measured parallel to a longitudinal axis of the guide surface which is greater than the first length.

25. A method as set forth in claim 1 further including spanning less than a distance between opposite sides of an end portion of the one bone in the one leg of the patient with a guide member, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool along a guide surface on the guide member and forming a cut surface having an extent in a direction parallel to a longitudinal axis of the guide surface which is greater than the extent of the guide member in a direction parallel to the longitudinal axis of the guide surface.

26. A method as set forth in claim 25 wherein said step of moving the cutting tool along the guide surface includes moving a central axis of the cutting tool between a first orientation relative to the longitudinal axis of the guide surface to a second orientation relative to the longitudinal axis of the guide surface.

27. A method as set forth in claim 25 wherein said step of moving the cutting tool along the guide surface includes cutting a portion of the one bone at a location which is offset past an end of the guide surface.

28. A method as set forth in claim 1 further including the step of moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second position which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg, said step of moving an ankle portion of the one leg between the first and second positions is performed while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the one leg of the patient is below the support surface.

29. A method as set forth in claim 1 further including the step of moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second position in which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane, the reference plane is a vertical plane containing a longitudinal central axis of the upper portion of the patient'"'"'s one leg, said step of moving the lower portion of the one leg between the first and second positions is performed while the lower portion of the one leg of the patient extends downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg is below the support surface.

30. A method as set forth in claim 1 wherein said step of supporting the patient on a support surface includes supporting a trunk portion of the patient on a main support surface with the upper portion of the patient'"'"'s one leg on a leg support surface which is disposed above the main support surface.

31. A method as set forth in claim 1 further including the step of moving a leading end of an endoscope through the incision in the one leg of the patient to a location in the knee portion of the one leg of the patient spaced from the incision while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and inspecting the location in the knee portion of the one leg of the patient spaced from the incision while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, said step of inspecting the location in the knee portion of the one leg of the patient includes viewing the location in the knee portion of the one leg of the patient through the endoscope.

32. A method as set forth in claim 31 wherein said step of viewing the location in the knee portion of the one leg of the patient through the endoscope includes viewing the implant through the endoscope.

33. A method as set forth in claim 31 wherein said step of inspecting the location in the knee portion of the one leg of the patient is at least partially performed prior to performance of said step of moving an implant in engagement with the one bone in the one leg of the patient.

34. A method as set forth in claim 31 further including the step of moving the one leg of the patient between flexed and extended conditions, said step of inspecting the location in the knee portion of the one leg of the patient is at least partially performed during movement of the one leg of the patient between the flexed and extended conditions.

35. A method as set forth in claim 1 further including the steps of generating images of the one bone in the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

36. A method as set forth in claim 1 further including the step of connecting the cutting tool with a robot, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool relative to the one bone under the influence of force transmitted to the cutting tool from the robot.

37. A method as set forth in claim 1 further including the step of cutting a patella in the knee portion of the one leg of the patient while the patella is disposed in a normal position relative to the knee portion of the one leg.

38. A method as set forth in claim 37 wherein said step of cutting the patella is performed with an inner side of the patella facing toward a posterior portion of the knee portion of the one leg and includes removing at least a portion of the inner side of the patella.

39. A method as set forth in claim 38 wherein said step of cutting the patella is at least partially performed with the lower portion of the one leg of the patient extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

40. A method as set forth in claim 1 further including the steps of positioning a guide member relative to the one bone in the one leg of the patient, said step of cutting the one bone in the one leg of the patient includes utilizing a guide surface on the guide member to position the cutting tool relative to the one bone during making of an initial portion of a cut in the one bone, and completing the cut in the one bone while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the one bone.

41. A method as set forth in claim 1 wherein said step of moving a cutting tool into engagement with at least one bone in the one leg of the patient includes moving a first cutting tool into engagement with the one bone, said step of cutting the one bone in the one leg of the patient includes making an initial portion of a cut in the one bone with the first cutting tool, said method further includes moving a second cutting tool into engagement with the one bone, and completing the cut in the one bone while guiding the second cutting tool with a surface formed by the first cutting tool during making of the initial portion of the cut in the one bone.

42. A method as set forth in claim 1 further including the steps of exposing a first portion of the one bone through the incision and effecting relative movement between the upper and lower portions of the patient'"'"'s one leg to expose a second portion of the one bone through the incision.

43. A method as set forth in claim 1 further including the step of providing an output signal which is a function of tension in a ligament extending between bones in the one leg of the patient.

44. A method as set forth in claim 43 wherein said step of providing an output signal which is a function of tension in a ligament includes positioning a transducer in the knee portion of the one leg of the patient and providing a transducer output signal which varies as a function of variations in tension in the ligament during relative movement between the upper and lower portions of the one leg of the patient.

45. A method as set forth in claim 1 wherein said step of positioning an implant in engagement with the one bone in the one leg of the patient includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant into engagement with the one bone in the one leg of the patient, moving the second portion of the implant into engagement with the one bone in the one leg of the patient, and interconnecting the first and second portions of the implant while they are disposed in the one leg of the patient.

46. A method as set forth in claim 45 wherein said step of interconnecting the first and second portions of the implant while they are disposed in the one leg of the patient includes bonding of material of the first portion of the implant to material of the second portion of the implant.

47. A method as set forth in claim 45 wherein said step of interconnecting the first and second portions of the implant while they are disposed in the one leg of the patient includes mechanically interconnecting the first and second portions of the implant while they are disposed in the one leg of the patient.

48. A method as set forth in claim 45 wherein said step of interconnecting the first and second portions of the implant while they are disposed in the one leg of the patient includes interconnecting the first and second portions of the implant with a member which extends between the first and second portions of the implant while they are disposed in the one leg of the patient.

49. A method as set forth in claim 1 further including the step of moving the lower portion of the one leg of the patient to effect relative movement between the incision and the one bone in the one leg of the patient.

50. A method as set forth in claim 49 wherein said step of moving the lower portion of the one leg of the patient includes applying force to the foot connected with the lower portion of the one leg of the patient.

51. A method as set forth in claim 1 including the steps of inserting an expandable device into the knee portion of the one leg of the patient and expanding the expandable device under the influence of fluid pressure to apply force against body tissue in the knee portion of the one leg.

52. A method as set forth in claim 51 wherein the expandable device is formed of a biodegradable material, said method further includes the step of closing the incision in the knee portion of the one leg of the patient while the expandable device is in the knee portion of the one leg of the patient.

53. A method as set forth in claim 51 further including the step of closing the incision in the knee portion of the one leg of the patient while the expandable device is in the knee portion of the one leg of the patient, and varying fluid pressure in the expandable device after performing said step of closing the incision.

54. A method as set forth in claim 51 further including the step of closing the incision in the knee portion of the one leg of the patient, said step of expanding the expandable device is performed prior to performance of said step of closing the incision.

55. A method as set forth in claim 1 wherein said step of cutting a bone in the one leg of the patient includes cutting only one condyle on a distal end portion of a femur in the upper portion of the one leg of the patient.

56. A method as set forth in claim 1 wherein said step of positioning an implant into engagement with the bone in the one leg of the patient includes moving a projection on the implant into the bone through an end surface on the bone and moving a portion of the implant into engagement with a side surface on the bone, and connecting the implant with the bone in the one leg of the patient with a fastener which extends through the portion of the implant which engages the side surface on the bone.

57. A method as set forth in claim 1 further including the step of moving an expandable device through the incision in the knee portion of the one leg of the patient along a path which extends between an end portion of the bone in the one leg of the patient and an end portion of a second bone in the knee portion of the one leg of the patient while lower portion of the one leg of the patient is suspended from the upper position of the one leg of the patient, and thereafter, expanding the expandable device under the influence of fluid pressure.

58. A method as set forth in claim 1 further including the step of moving an expandable device into the knee portion of he one leg of the patient prior to performance of said step of making an incision in the knee portion of the one leg of the patient, stretching body tissue in the knee portion of the one leg of the patient by expanding the expandable device under the influence of fluid pressure, and thereafter, performing said step of making an incision in the knee portion of the one leg of the patient, said step of making an incision in the knee portion of the one leg of the patient includes making at least a portion of the incision in body tissue stretched by expanding the expandable device.

59. A method as set forth in claim 1 further including the step of mounting a guide member on a surface of a femur in the upper portion of the one leg of the patient, said step of mounting a guide member on a surface of a femur includes mounting the guide member on a surface which is disposed on a distal end portion of the femur and which extends along a longitudinal central axis of the femur and extends through an axis which extends through first and second condyles on the distal end portion of the femur, said step of cutting the bone in the one leg of the patient includes moving leg of the patient includes moving a tool along a path which extends along guide surfaces on the guide member and cutting the distal end portion of the femur to form a cut surface which extends along the axis which extends through the first and second condyles.

60. A method as set forth in claim 1 wherein said step of moving an implant into engagement with the bone in the one leg of the patient includes moving a implant containing bone growth promoting materials into engagement with the bone, and growing new bone from the bone into the implant.

61. A method as set forth in claim 1 wherein said step of cutting the bone in the one leg of the patient includes forming a recess in an articular surface on the bone, said step of positioning an implant includes positioning the implant in the recess in the bone.

62. A method as set forth in claim 61 further including the step of growing new bone from the bone into the recess.

63. A method as set forth in claim 1 wherein said step of positioning an implant includes moving an implant which is at least partially formed by a layer containing bone particles and a layer containing cartilage into engagement with the bone.

64. A method as set forth in claim 1 further including the steps of cutting a patella in the knee portion of the one leg of the patient, and cutting proximal end portion of a tibia in the one leg of the patient after cutting the patella in the one leg of the patient, said step of cutting the bone in the one leg of the patient includes cutting a distal end portion of a femur in the one leg of the patient after cutting the proximal end portion of the tibia in the one leg of the patient.

65. A method as set forth in claim 64 wherein said step of cutting the patella in the knee portion of the one leg of the patient is performed with an inner side of the patella facing toward the distal end portion of the femur.

66. A method as set forth in claim 64 wherein said step of cutting the patella in the knee portion of the one leg of the patient is performed with the lower portion of the one leg of the patient extending downward from the upper portion of the one leg of the patient and with a foot connected with the lower portion of the one leg of the patient below the support surface.

67. A method as set forth in claim 64 wherein said step of cutting the proximal end portion of the tibia in the one leg of the patient is performed with the lower portion of the one leg of the patient extending downward from the upper portion of the one leg of the patient and with a foot connected with the lower portion of the one leg of the patient below the support surface.

68. A method as set forth in claim 1 wherein said step of cutting the bone in the one leg of the patient includes cutting a distal end portion of a femur in the one leg of the patient to form a cut surface which extends only part way across the distal end portion of the femur, said step of positioning an implant in the one leg of the patient includes positioning an implant which extends only part way across the distal end portion of the femur adjacent to the cut surface which extends only part way across the distal end portion of the femur.

69. A method as set forth in claim 1 further including the step of positioning an expandable device in a posterior portion of the knee portion of the one leg of the patient, expanding the expandable device under the influence of fluid pressure, and moving body tissue in a direction away from an anterior portion of the one leg of the patient under the influence of force applied against the body tissue by the expandable device during expansion of the expandable device.

70. A method as set forth in claim 1 wherein said step of positioning an implant in the one leg of the patient includes positioning a first implant in engagement a distal end portion of a femur in the upper portion of the one leg of the patient, said method further includes the steps of positioning a second implant in engagement with a proximal end portion of a tibia in the lower portion of the one leg of the patient, positioning an expandable device between the first and second implants, and applying force against the first and second implants by expanding the expandable device under the influence of fluid pressure.

71. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient with a lower portion of one leg of the patient suspended from an upper portion of the one leg, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg is suspended from the upper portion of the one leg, cutting a bone in the one leg of the patient while the lower portion of the one leg is suspended from the upper portion of the one leg, and positioning an implant in the knee portion of the one leg of the patient while the lower portion of the one leg is suspended from the upper portion of the one leg.

72. A method as set forth in claim 71 further including the step of closing the incision in the knee portion of the one leg of the patient while the lower portion of the one leg is suspended from the upper portion of the one leg.

73. A method as set forth in claim 71 further including the step of hyperflexing a joint in the knee portion of the one leg of the patient after making the incision in the knee portion of the one leg and while the lower portion of the one leg is suspended from the upper portion of the one leg.

74. A method as set forth in claim 71 further including the step of distracting a joint in the knee portion of the one leg of the patient after making the incision in the knee portion of the one leg and while the lower portion of the one leg is suspended from the upper portion of the one leg.

75. A method as set forth in claim 71 further including the step of hyperflexing a hip at a proximal end portion of the one leg of the patient during performance of said steps of making an incision and cutting a bone.

76. A method as set forth in claim 71 wherein said step of making an incision includes making an incision having a length between seven and thirteen centimeters.

77. A method as set forth in claim 71 further including the step of supporting the upper portion of the one leg of the patient with a leg holder during performance of said steps of making an incision and cutting bone.

78. A method as set forth in claim 71 wherein said step of making an incision includes making an incision at a location adjacent to a medial edge portion of a patella in the knee portion of the one leg of the patient.

79. A method as set forth in claim 78 wherein said step of cutting a bone is performed with the patella offset laterally of a location where the bone is cut and with an inner side of the patella facing toward bones in the knee portion of the one leg of the patient.

80. A method as set forth in claim 71 further including the step of positioning a guide member adjacent to a distal end of a femur in the upper portion of the leg of the patient with the guide member extending across less than two thirds (⅔

) of a distance between opposite sides of the distal end of the femur, said step of cutting the bone includes moving a cutting tool along a surface on the guide member.

81. A method as set forth in claim 71 further including the step of balancing ligaments connected with bones in the one leg of the patient while the lower portion of the one leg of the patient is suspended from the upper portion of the one leg of the patient.

82. A method as set forth in claim 71 further including the step of cutting a patella in the knee portion of the one leg of the patient to remove an inner surface of the patella with the one leg of the patient extended.

83. A method as set forth in claim 71 wherein said step of cutting the bone in the one leg of the patient includes pivoting a cutting tool to move an end portion of the cutting tool along an arcuate path relative to the bone in the one leg of the patient.

84. A method as set forth in claim 71 further including the step of positioning a guide surface relative to the bone in the one leg of the patient, said step of cutting the bone includes moving a cutting tool along the guide surface between opposite end portions of the guide surface and pivoting the cutting tool to move an end portion of the cutting tool along an arcuate path.

85. A method as set forth in claim 71 further including the step of providing a drape system which overlies the patient, extends beneath the one leg of the patient, and is connected with a surgeon who is to perform said step of cutting the bone.

86. A method as set forth in claim 71 further including the step of expanding the incision by applying force against opposite sides of the incision during performance of said step of cutting the bone.

87. A method as set forth in claim 71 further including the steps of moving a guide member having opposite ends which are spaced apart by a distance which is less than a distance between lateral and medial epicondyles an a femur in the upper portion of the one leg of the patient into the incision, positioning the guide member adjacent to lateral and medial condyles on the femur in the one leg of the patient with opposite ends of the guide member substantially aligned with an axis through the lateral and medial epicondyles on the femur in the one leg of the patient, said step of cutting bone in the one leg of the patient includes cutting bone on the lateral and medial condyles on the femur in the one leg of the patient with the cutting tool and moving the cutting tool along a guide surface on the guide member.

88. A method as set forth in claim 71 wherein said step of supporting the patient with the lower portion of one leg of the patient suspended from an upper portion of the one leg includes supporting the patient in a supine position on a support surface with the upper portion of the one leg of the patient disposed above and spaced from the support surface.

89. A method as set forth in claim 71 further including the steps of expanding the incision by applying force against opposite edge portions of the incision and offsetting a patella in the knee portion of the one leg of the patient from its normal position to an offset position, said step of cutting bone in the one leg of the patient is performed with the patella offset from its normal position and with an inner side of the patella facing inward.

90. A method as set forth in claim 89 further including the steps of moving a guide member through the incision into engagement with an end portion of a femur in the upper portion of the one leg of the patient, connecting the guide member with the end portion of the femur with one end of the guide member offset laterally from a medial edge portion of a medial condyle on the end portion of the femur and with an end of the guide member opposite from the one end of the guide member offset medially from a lateral edge portion of a lateral condyle on the end portion of the femur.

91. A method as set forth in claim 71 further including the step of moving a leading end of an endoscope through the incision in the one leg of the patient to a location remote from the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is suspended from the upper portion of the one leg, and inspecting the location remote from the incision in the knee portion of the one leg, said step of inspecting the location remote from the incision in the knee portion of the one leg includes viewing tissue in the knee portion of the one leg of the patient through the endoscope while the lower portion of the one leg is suspended from the upper portion of the one leg.

92. A method as set forth in claim 91 wherein said step of viewing tissue in the knee portion of the one leg of the patient through the endoscope includes viewing the implant through the endoscope.

93. A method as set forth in claim 91 wherein said step of inspecting the location remote from the incision in the knee portion of the one leg of the patient is at least partially performed prior to performance of said step of positioning an implant in the knee portion of the one leg.

94. A method as set forth in claim 91 further including the step of moving the one leg of the patient between flexed and extended conditions, said step of inspecting the location remote from the incision in the knee portion of the one leg of the patient is at least partially performed during movement of the one leg of the patient between flexed and extended conditions.

95. A method as set forth in claim 71 further including the steps of generating images of a bone in the one leg of the patient while the lower portion of the one leg of the patient is suspended from the upper portion of the one leg.

96. A method as set forth in claim 71 further including the step of connecting a cutting tool with a robot, said step of cutting the bone in the one leg of the patient includes moving the cutting tool relative to the one bone under the influence of force transmitted to the cutting tool from the robot.

97. A method as set forth in claim 71 further including the step of cutting a patella in the knee portion of the one leg of the patient while the patella is disposed in situ.

98. A method as set forth in claim 97 wherein said step of cutting the patella is performed with an inner side of the patella facing toward a posterior portion of the knee portion of the one leg and includes removing at least a portion of the inner side of the patella.

99. A method as set forth in claim 98 wherein said step of cutting the patella is at least partially performed with the lower portion of the one leg of the patient is suspended from the upper portion of the one leg of the patient.

100. A method as set forth in claim 71 further including the steps of positioning a guide member relative to the one bone in the one leg of the patient, said step of cutting the one bone in the one leg of the patient includes utilizing a guide surface on the guide member to position the cutting tool relative to the one bone during making of an initial portion of a cut in the one bone, and completing the cut in the one bone while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the one bone.

101. A method as set forth in claim 71 wherein said step of cutting the one bone in the one leg of the patient includes making an initial portion of a cut in the one bone with a first cutting tool, and completing the cut in the one bone while guiding a second cutting tool with a surface formed by the first cutting tool during making of the initial portion of the cut in the one bone.

102. A method as set forth in claim 71 further including the steps of exposing a first portion of the one bone through the incision and effecting relative movement between the upper and lower portions of the patient'"'"'s one leg to expose a second portion of the one bone through the incision.

103. A method as set forth in claim 71 further including the step of providing an output signal which is a function of tension in a ligament extending between bones in the one leg of the patient.

104. A method as set forth in claim 103 wherein said step of providing an output signal which is a function of tension in a ligament includes positioning a container holding fluid in the knee portion of the one leg of the patient and providing an output signal which varies as a function of variations in fluid pressure in the container during relative movement between the upper and lower portion of the one leg of the patient.

105. A method as set forth in claim 71 wherein said step of positioning an implant in engagement with the one bone in the one leg of the patient includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone in the one leg of the patient, moving the second portion of the implant through the incision into engagement with the one bone in the one leg of the patient, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

106. A method as set forth in claim 105 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes bonding of material of the first portion of the implant to material of the second portion of the implant.

107. A method as set forth in claim 105 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes mechanically interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

108. A method as set forth in claim 105 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes interconnecting the first and second portions of the implant with a member which extends between the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

109. A method as set forth in claim 71 further including the step of moving the lower portion of the one leg of the patient to effect relative movement between the incision and the one bone in the one leg of the patient.

110. A method as set forth in claim 109 wherein said step of moving the lower portion of the one leg of the patient includes applying force to a foot connected with the lower portion of the one leg of the patient.

111. A method as set forth in claim 71 further including the steps of inserting an expandable device into the knee portion of the one leg of the patient and expanding the expandable device under the influence of fluid pressure to apply force against body tissue in the knee portion of the one leg.

112. A method as set forth in claim 111 wherein the expandable device is formed of a biodegradable material, said method further includes the step of closing the incision in the knee portion of the one leg of the patient while the expandable device is in the knee portion of the one leg of the patient.

113. A method as set forth in claim 111 further including the step of closing the incision in the knee portion of the one leg of the patient while the expandable device is in the knee portion of the one leg of the patient, and varying fluid pressure in the expandable device after performing said step of closing the incision.

114. A method as set forth in claim 111 further including the step of closing the incision in the knee portion of the one leg of the patient, said step of expanding the expandable device is performed prior to performance of said step of closing the incision.

115. A method as set forth in claim 71 wherein said step of cutting a bone in the one leg of the patient includes cutting only one condyle on a distal end portion of a femur in the upper portion of the one leg of the patient.

116. A method as set forth in claim 71 wherein said step of positioning an implant into engagement with the bone in the one leg of the patient includes moving a projection on the implant into the bone through an end surface on the bone and moving a portion of the implant into engagement with a side surface on the bone, and connecting the implant with the bone in the one leg of the patient with a fastener which extends through the portion of the implant which engages the side surface on the bone.

117. A method as set forth in claim 71 further including the step of moving an expandable device through the incision in the knee portion of the one leg of the patient along a path which extends between an end portion of the bone in the one leg of the patient and an end portion of a second bone in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is suspended from the upper position of the one leg of the patient, and thereafter, expanding the expandable device under the influence of fluid pressure.

118. A method as set forth in claim 71 further including the step of moving an expandable device into the knee portion of the one leg of the patient prior to performance of said step of making an incision in the knee portion of the one leg of the patient, stretching body tissue in the knee portion of the one leg of the patient by expanding the expandable device, and thereafter, performing said step of making an incision in the knee portion of the one leg of the patient, said step of making an incision in the knee portion of the one leg of the patient includes making at least a portion of the incision in body tissue stretched by expanding the expandable device.

119. A method as set forth in claim 71 further including the step of mounting a guide member on a surface of a femur in the upper portion of the one leg of the patient, said step of mounting a guide member on a surface of a femur includes mounting the guide member on a surface which is disposed on a distal end portion of the femur and which extends along a longitudinal central axis of the femur and extends through an axis which extends through first and second condyles on the distal end portion of the femur, said step of cutting the bone in the one leg of the patient includes moving a tool along a path which extends along guide surfaces on the guide member and cutting the distal end portion of the femur to form a cut surface which extends along the axis which extends through the first and second condyles.

120. A method as set forth in claim 71 wherein said step of moving an implant into engagement with the bone in the one leg of the patient includes moving a implant containing bone growth promoting materials into engagement with the bone, and growing new bone from the bone into the implant.

121. A method as set forth in claim 71 wherein said step of cutting the bone in the one leg of the patient includes forming a recess in an articular surface on the bone, said step of positioning an implant includes positioning the implant in the recess in the bone.

122. A method as set forth in claim 71 further including the step of growing new bone from the bone into the recess.

123. A method as set forth in claim 71 wherein said step of positioning an implant includes moving an implant which is at least partially formed by a layer containing bone particles and a layer containing cartilage into engagement with the bone.

124. A method as set forth in claim 71 further including the steps of cutting a patella in the knee portion of the one leg of the patient, and cutting a proximal end portion of a tibia in the one leg of the patient after cutting the patella in the one leg of the patient, said step of cutting the bone in the one leg of the patient includes cutting a distal end portion of a femur in the one leg of the patient after cutting the proximal end portion of the tibia in the one leg of the patient.

125. A method as set forth in claim 124 wherein said step of cutting the patella in the knee portion of the one leg of the patient is performed with an inner side of the patella facing toward the distal end portion of the femur.

126. A method as set forth in claim 124 wherein said step of cutting the patella in the knee portion of the one leg of the patient is performed with the lower portion of the one leg of the patient extending downward from the upper portion of the one leg of the patient and with a foot connected with the lower portion of the one leg of the patient below the support surface.

127. A method as set forth in claim 124 wherein said step of cutting the proximal end portion of the tibia in the one leg of the patient is performed with the lower portion of the one leg of the patient extending downward from the upper portion of the one leg of the patient and with a foot connected with the lower portion of the one leg of the patient below the support surface.

128. A method as set forth in claim 71 wherein said step of cutting the bone in the one leg of the patient includes cutting a distal end portion of a femur in the one leg of the patient to form a cut surface which extends only part way across the distal end portion of the femur, said step of positioning an implant in the one leg of the patient includes positioning an implant which extends only part way across the distal end portion of the femur adjacent to the cut surface which extends only part way across the distal end portion of the femur.

129. A method as set forth in claim 71 further including the step of positioning an expandable device in a posterior portion of the knee portion of the one leg of the patient, expanding the expandable device, and moving body tissue in a direction away from an anterior portion of the one leg of the patient under the influence of force applied against the body tissue by the expansible device during expansion of the expandable device.

130. A method as set forth in claim 71 wherein said step of positioning an implant in the one leg of the patient includes positioning a first implant in engagement a distal end portion of a femur in the upper portion of the one leg of the patient, said method further includes the steps of positioning a second implant in engagement with a proximal end portion of a tibia in the lower portion of the one leg of the patient, positioning an expandable device between the first and second implants, and applying force against the first and second implants by expanding the expandable device.

132. A method as set forth in claim 131 wherein said step of making an incision in a knee portion of one leg of the patient includes making the incision adjacent to a medial edge portion of the patella, said step of moving the patella from its normal position to an offset position includes moving the patella laterally relative to the knee portion of the one leg of the patient.

133. A method as set forth in claim 131 wherein said step of making an incision in the knee portion of one leg of the patient includes making an incision having a length between seven and thirteen centimeters.

134. A method as set forth in claim 131 further including the step of expanding the incision by applying force against opposite edge portion of the incision, said step of moving the patella from its normal position to an offset position is performed contemporaneously with performance of said step of expanding the incision.

135. A method as set forth in claim 131 wherein said step of moving a cutting tool to cut bone on the end portion of the femur includes cutting bone on at least one of lateral and medial condyles disposed at the end portion of the femur.

136. A method as set forth in claim 131 further including the step of connecting a guide member with a femur in the one leg of the patient with a first end portion of the guide member in engagement with a lateral condyle of the femur and offset medially from a lateral edge portion of the lateral condyle and with a second end portion of the guide member in engagement with a medial condyle of the femur and offset laterally from a medial edge portion of the medial condyle.

137. A method as set forth in claim 131 including the steps of applying force against a first edge portion of the incision with a first retractor and applying force against a second edge portion of the incision with a second retractor, said step of moving the patella to an offset position includes moving the patella under the influence of force transmitted from the second retractor to the patella.

138. A method as set forth in claim 131 further including the steps of moving a guide member having opposite ends which are spaced apart by a distance which is less than a distance between lateral and medial epicondyles on a femur in the upper portion of the one leg of the patient into the incision, positioning the guide member on the femur in the one leg of the patient with opposite ends of the guide member aligned with an axis through lateral and medial epicondyles on the femur in the one leg of the patient, said step of moving a cutting tool to cut the one bone in the one leg of the patient includes cutting bone on the lateral and medial condyles on the femur in the one leg of the patient and moving the cutting tool along a guide surface on the guide member.

139. A method as set forth in claim 131 further including the steps of moving an implant through the incision while the patella is offset from its normal position with an inner side of the patella facing inward, and connecting the implant with an end portion of the femur in the upper portion of the leg of the patient while the patella is offset from its normal position with an inner side of the patella facing inward.

140. A method as set forth in claim 131 further including the steps of supporting the patient with a lower portion of the one leg suspended from an upper portion of the one leg during performance of said steps of making the incision in the knee portion of the one leg and moving the patella to an offset position with an inner side of the patella facing inward.

141. A method as set forth in claim 131 further including the step of moving a leading end of an endoscope through the incision in the one leg of the patient to a posterior portion of the knee portion of the one leg of the patient, and inspecting the posterior portion of the knee portion of the one leg of the patient, said step of inspecting the posterior portion of the knee portion of the one leg of the patient includes viewing the posterior portion of the knee portion of the one leg of the patient through the endoscope.

142. A method as set forth in claim 141 further including the step of moving the one leg of the patient between flexed and extended conditions, said step of inspecting the posterior portion of the knee portion of the one leg of the patient is at least partially performed during movement of the one leg of the patient between the flexed and extended conditions.

143. A method as set forth in claim 131 further including the step of cutting the patella in the knee portion of the one leg of the patient while the patella is disposed in a normal position relative to the knee portion of the one leg.

144. A method as set forth in claim 143 wherein said step of cutting the patella is performed with the inner side of the patella facing toward the posterior portion of the knee portion of the one leg and includes removing at least a portion of the inner side of the patella.

145. A method as set forth in claim 144 wherein said step of cutting the patella is at least partially performed with a lower portion of the one leg of the patient suspended from an upper portion of the one leg of the patient.

146. A method as set forth in claim 131 wherein said step of moving a cutting tool to cut bone on an end portion of the femur includes making of an initial portion of a cut in the femur, and completing the cut in the femur while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the femur.

147. A method as set forth in claim 131 further including the steps of exposing a first portion of the femur through the incision and effecting relative movement between upper and lower portions of the patient'"'"'s one leg to expose a second portion of the femur through the incision.

148. A method as set forth in claim 131 further including the step of providing an output signal which is a function of tension in a ligament extending between bones in the one leg of the patient.

149. A method as set forth in claim 138 wherein said step of providing an output signal which is a function of tension in a ligament includes positioning a transducer between the ligament and a bone in the knee portion of the one leg of the patient and providing an output signal which varies as a function of variations in force applied against the transducer during relative movement between upper and lower portions of the one leg of the patient.

151. A method as set forth in claim 150 further including the step of supporting the patient with a lower portion of the one leg suspended from an upper portion of the one leg, the upper portion of the one leg of the patient being connected with the first portion of the sterile drape system with a distal portion of the upper portion of the one leg of the patient extending away from a side of the first portion of the sterile drape system which faces away from the patient.

152. A method as set forth in claim 151 further including the step of making an incision in the knee portion of the one leg while the lower portion of the one leg is suspended from the upper portion of the one leg and a foot connected with the lower portion of the one leg is disposed adjacent to a side of the second portion of the sterile drape system.

153. A method as set forth in claim 152 further including the step of cutting a bone exposed through the incision while the lower portion of the one leg is suspended from the upper portion of the one leg and the foot connected with the lower portion of the one leg is disposed adjacent to the side of the second portion of the sterile drape system.

154. A method as set forth in claim 153 further including the step of positioning an implant in the knee portion of the one leg of the patient while the lower portion of the one leg is suspended from the upper portion of the one leg and the foot connected with the lower portion of the one leg is disposed adjacent to the side of the second portion of the sterile drape system.

155. A method as set forth in claim 154 further including the step of moving the second portion of the sterile drape system relative to the first portion of the sterile drape system during movement of the surgeon relative to the patient during performance of one or more of said steps of making an incision in the knee portion of the one leg, cutting a bone exposed through the incision, and positioning an implant in the knee portion of the one leg.

156. A method as set forth in claim 150 further including the step of connecting the second portion of the sterile drape system with the first portion of the sterile drape system with a plurality of fasteners.

157. A method as set forth in claim 150 wherein said step of connecting a second portion of the sterile drape system with the body of the surgeon includes securing the second portion of the sterile drape system around a waist portion of the surgeon.

158. A method as set forth in claim 150 wherein said step of connecting a second portion of the sterile drape system with the body of the surgeon includes putting on of a sterile surgical gown by the surgeon with the second portion of the sterile drape system connected with the surgical gown.

159. A method as set forth in claim 150 wherein said step of maintaining a sterile field between the surgeon and the patient with the second portion of the sterile drape system during movement of the surgeon'"'"'s body relative to the patient includes moving an end portion of the second portion of the sterile drape system connected with the surgeon'"'"'s body toward and away from the patient, lowering an intermediate portion of the second portion of the sterile drape system as the surgeon'"'"'s body moves toward the patient, and raising the intermediate portion of the second portion of the sterile drape system as the surgeon'"'"'s body moves away from the patient.

161. A method as set forth in claim 160 further including the step of connecting a cutting tool with a robot, said step of cutting a bone includes moving the cutting tool relative to the bone under the influence of force transmitted to the cutting tool from the robot.

162. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg includes generating fluoroscopic images of the knee portion of the one leg.

163. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg is at least partially performed after performing said step of cutting a bone and prior to performing said step of connecting the implant with the bone.

164. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg is at least partially performed after performance of said step of connecting the implant with the bone.

165. A method as set forth in claim 160 wherein said step of cutting a bone includes cutting a first bone in the one leg of the patient, said method further includes cutting a second bone in the one leg of the patient, said step of generating images of the knee portion of the one leg is at least partially performed after cutting the first bone in the one leg of the patient and prior to cutting of the second bone in the one leg of the patient.

166. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg of the patient is at least partially performed during performance of said step of cutting a bone.

167. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg of the patient is at least partially performed during performance of said step of connecting the implant with the bone in the one leg of the patient.

168. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg of the patient is at least partially performed during performance of said step of bending the knee portion of the one leg of the patient.

169. A method as set forth in claim 168 wherein said step of bending the knee portion of the one leg of the patient is at least partially performed after performance of said step of cutting a bone and prior to performance of said step of connecting the implant with the bone.

170. A method as set forth in claim 168 wherein said step of bending the knee portion of the one leg of the patient is at least partially performed after performance of said step of connecting the implant with the bone.

171. A method as set forth in claim 160 wherein said step of cutting a bone includes cutting a first bone in the one leg of the patient, said method further includes cutting a second bone in the one leg of the patient, said step of connecting the implant with the bone includes connecting a first implant with the first bone, said method further includes moving a second implant into the incision, and connecting the second implant with the second bone, said step of bending the knee portion of the one leg of the patient includes providing relative movement between the first and second implants, said step of generating images of the knee portion of the one leg of the patient includes generating images of the first and second implants with the first and second implants in a plurality of different positions relative to each other.

172. A method as set forth in claim 171 wherein said step of generating images of the first and second implants is at least partially performed during performance of said step of bending the knee portion of the one leg of the patient.

173. A method as set forth in claim 171 wherein said step of generating images includes generating an image of at least a portion of the first bone after performing said step of cutting the first bone and prior to performance of said step of connecting the first implant with the first bone and generating an image of at least a portion of the second bone after performing said step of cutting the second bone and prior to performance of said step of connecting the second implant with the second bone.

174. A method as set forth in claim 160 wherein said step of bending the knee portion of the one leg of the patient includes moving the one leg of the patient between a flexed condition and an extended condition, said step of generating images of the knee portion of the one leg of the patient includes generating a first image of the knee portion of the one leg of the patient when the one leg of the patient is in the flexed condition and generating a second image of the knee portion of the one leg of the patient when the one leg of the patient is in the extended condition.

175. A method as set forth in claim 160 wherein said step of bending the knee portion of the one leg of the patient includes moving the one leg of the patient between a flexed condition and an extended condition, said step of generating images of the knee portion of the one leg of the patient includes generating images of the knee portion during movement of the one leg of the patient between the flexed condition and the extended condition.

176. A method as set forth in claim 160 wherein said step of making an incision in a knee portion of the one leg of the patient is performed with a lower portion of the one leg suspended from an upper portion of the one leg.

177. A method as set forth in claim 176 wherein said step of closing the incision is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg.

178. A method as set forth in claim 160 wherein said step of cutting a bone is performed with a lower portion of the one leg of the patient suspended from an upper portion of the one leg.

179. A method as set forth in claim 160 wherein said step of generating images of the knee portion of the one leg of the patient is at least partially performed with a lower portion of the one leg of the patient suspended from an upper portion of the one leg.

180. A method as set forth in claim 160 wherein said step of bending the knee portion of the one leg of the patient is at least partially performed with a lower portion of the one leg of the patient suspended from an upper portion of the one leg.

181. A method as set forth in claim 160 wherein said step of making an incision in a knee portion of the one leg of the patient includes making the incision at a location adjacent to an edge portion of a patella in the one leg of the patient.

182. A method as set forth in claim 181 further including the steps of expanding the incision by applying force against opposite edge portions of the incision, and moving the patella from its normal position to an offset position with an inner side of the patella facing inward, said step of generating images of the knee portion of the one leg of the patient is at least partially performed with the patella in the offset position.

183. A method as set forth in claim 160 further including the steps of moving a guide member through the incision into engagement with an end portion of a femur in the one leg of the patient, said step of cutting a bone exposed through the incision includes moving a cutting tool along a guide surface on the guide member, said step of generating images of the knee portion of the one leg of the patient is at least partially performed with the guide member in engagement with the end portion of the femur.

184. A method as set forth in claim 160 wherein said step of making an incision in the knee portion of the one leg of the patient includes making the incision adjacent to an edge portion of a patella in the knee portion of the one leg of the patient, said method further includes moving the patella from its normal position relative to the knee portion of the one leg of the patient with an inner side of the patella facing toward a posterior portion of the knee portion, said step of generating images of the knee portion of the one leg of the patient is at least partially performed after moving the patella offset from its normal position.

186. A method as set forth in claim 185 wherein said step of moving a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed prior to performance of said step of positioning an implant in engagement with the one bone in the one leg of the patient.

187. A method as set forth in claim 185 wherein said step of moving the lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed after performance of said step of positioning an implant in engagement with the one bone in the one leg of the patient.

188. A method as set forth in claim 185 wherein said step of moving a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

189. A method as set forth in claim 185 wherein the patient is disposed in a supine orientation on the support surface during performance of said step of moving a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient, said method further includes the step of supporting the upper portion of the one leg of the patient at a level disposed above the support surface with a leg support having a surface which engages a posterior surface area on an outside of the upper portion of the one leg during performance of said step of moving the lower portion of the one leg of the patient relative to an upper portion of the one leg.

190. A method as set forth in claim 185 further including the step of rotating the lower portion of the one leg of the patient about an axis extending along the lower portion of the one leg of the patient while the lower portion of the one leg is extending downward from the upper portion and the foot connected with the lower portion of the one leg is below the support surface.

191. A method as set forth in claim 185 further including the step of distracting a joint in the knee portion of the one leg of the patient under the influence of force resulting from the weight of the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

193. A method as set forth in claim 192 wherein said step of rotating a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed prior to performance of said step of positioning an implant in engagement with the one bone in the one leg of the patient.

194. A method as set forth in claim 192 wherein said step of rotating the lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed after performance of said step of positioning an implant in engagement with the one bone in the one leg of the patient.

195. A method as set forth in claim 192 wherein said step of rotating a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

196. A method as set forth in claim 192 wherein the patient is disposed in a supine orientation on the support surface during performance of said step of rotating a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient, said method further includes the step of supporting the upper portion of the one leg of the patient at a level disposed above the support surface with a leg support having a surface which engages a posterior surface area on an outside of the upper portion of the one leg.

197. A method as set forth in claim 192 further including the step of distracting a joint in the knee portion of the one leg of the patient under the influence of force resulting from the weight of the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

199. A method as set forth in claim 198 wherein said steps of making an incision in a knee portion of the one leg, cutting the one bone, and positioning an implant in engagement with the one bone are at least partially performed with the lower portion of the one leg suspended from the upper portion of the one leg of the patient.

200. A method as set forth in claim 198 further including the step of distracting a joint in the knee portion of the one leg of the patient under the influence of force resulting from the weight of the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

201. A method as set forth in claim 198 further including the step of moving a patella in the knee portion of the one leg of the patient from a normal position of the patella to an offset position with an inner side of the patella facing inward, said step of cutting the one bone in the one leg of the patient being at least partially performed while the patella is in the offset position with the inner side of the patella facing inward.

202. A method as set forth in claim 198 further including the step of cutting the patella in the knee portion of the one leg of the patient when the patella is in the normal position with the inner side of the patella facing inward while the upper portion of the one leg is supported above the support surface by the leg support.

203. A method as set forth in claim 202 wherein said step of cutting the patella includes removing at least a portion of the inner side of the patella while the patella is in its normal position with the inner side facing inward.

204. A method as set forth in claim 198 further including the step of positioning a guide member relative to the one bone in the one leg of the patient, said step of cutting the one bone includes utilizing a guide surface on the guide member to position the cutting tool relative to the one bone during making of an initial portion of a cut in the one bone, and completing the cut in the one bone while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the one bone.

205. A method as set forth in claim 198 further including the steps of exposing a first portion of the one bone through the incision and effecting relative movement between the upper and lower portions of the patient'"'"'s one leg to expose a second portion of the one bone through the incision.

206. A method as set forth in claim 198 further including the steps of moving a guide member having opposite ends which are spaced apart by a distance which is less than two thirds (⅔

) of a distance between tips on lateral and medial epicondyles on a femur in an upper portion of the one leg of the patient into the incision, positioning the guide member on the femur in the one leg of the patient with opposite ends of the guide member substantially aligned with an axis through the lateral and medial epicondyles on the femur in the one leg of the patient, said step of cutting the one bone includes moving the cutting tool along the guide surface on the guide member and cutting the femur in the one leg with the cutting tool.

207. A method as set forth in claim 198 wherein said step of making an incision in the knee portion of the one leg of the patient includes making an incision which has a length of between about seven centimeters and about thirteen centimeters when the lower portion of the one leg extends downward from the upper portion of the one leg.

208. A method as set forth in claim 198 further including the step of pivoting the lower portion of the one leg of the patient sideways relative to the upper portion of the one leg of the patient while the lower portion of the one leg is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg is below the support surface, said step of pivoting the lower portion of the one leg of the patient sideways relative to the upper portion of the one leg is performed while the upper portion of the one leg is supported above the support surface by the leg support.

209. A method as set forth in claim 198 further including the step of rotating the lower portion of the one leg of the patient about an axis extending along the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg is below the support surface, said step of rotating the lower portion of the one leg is performed while the upper portion of the one leg is supported above the support surface by the leg support.

210. A method as set forth in claim 198 further including the step of closing the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, said step of closing the incision being performed while the upper portion of the one leg is supported above the support surface by the leg support.

211. A method as set forth in claim 198 further including the step of positioning a guide member relative to the one bone with a portion of the guide member overlying a portion of skin which encloses the one bone, and connecting the guide member with the one bone by moving a member through the skin which underlies the guide member into the one bone, said step of cutting the one bone includes moving the cutting tool along a guide surface on the guide member.

212. A method as set forth in claim 198 further including the step of moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second position in which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while the upper portion of the one leg is supported above the support surface by the leg support, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

213. A method as set forth in claim 198 further including the step of moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second position in which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while the upper portion of the one leg is supported above the support surface by the leg support, the reference plane is a vertical plane containing a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

131. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of making an incision in a knee portion of one leg of the patient, moving a patella in the knee portion of the one leg from its normal position to an offset position with an inner side of the patella facing inward, and moving a cutting tool to cut bone on an end portion of a femur in the one leg of the patient while the patella is offset from its normal position with an inner side of the patella facing inward.

150. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of positioning a first portion of a sterile drape system over the patient with at least a knee portion of one leg of the patient exposed, connecting a second portion of the sterile drape system with a body of a surgeon who is to perform surgery on the knee portion of the one leg of the patient with the second portion of the sterile drape system extending beneath the one leg of the patient and with the second portion of the sterile drape system connected with the first portion of the sterile drape system, and maintaining a sterile field between the surgeon and the patient with the second portion of the sterile drape system during movement of the surgeon'"'"'s body relative to the patient.

160. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of making an incision in a knee portion of one leg of the patient, cutting a bone in the one leg of the patient, moving an implant into the incision, connecting the implant with the bone, bending the knee portion of the one leg of the patient, generating images of the knee portion of the one leg of the patient with a lower portion of the one leg in a plurality of different positions relative to an upper portion of the one leg after performing said step of making an incision in the knee portion of the one leg, and, thereafter, closing the incision.

185. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, positioning an implant in engagement with the one bone in the one leg of the patient, moving a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient along a path extending through lateral and medial surfaces of a foot connected with a lower portion of the one leg, said step of moving a lower portion of the one leg is performed while the lower portion of the one leg extends downward from the upper portion of the one leg and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and, thereafter, closing the incision, said step of moving the lower portion of the one leg of the patient is at least partially performed after performing said step of cutting the one bone and prior to performance of said step if closing the incision.

192. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, positioning an implant in engagement with the one bone in the one leg of the patient, rotating a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient about an axis extending along the lower portion of the one leg while the lower portion of the one leg extends downward from the upper portion of the one leg and a foot connected with the lower portion of the one leg of the patient is below the support surface, and, thereafter, closing the incision, said step of rotating a lower portion of the one leg is at least partially performed after performing said step of cutting the one bone and prior to performance of said step of closing the incision.

198. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of one leg of the patient, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, positioning an implant in engagement with the one bone in the one leg of the patient, and supporting an upper portion of the one leg of the patient above the support surface with a leg support having a surface which is disposed beneath a posterior surface area on the upper portion of the one leg, said steps of making an incision in a knee portion of the one leg, cutting the one bone, and positioning an implant in engagement with the one bone being performed with a lower portion of the one leg extending downward from an upper portion of the one leg and a foot connected with the lower portion of the one leg below the support surface while the upper portion of the one leg is supported above the support surface by the leg support.

214. A method of performing surgery on a patient'"'"'s knee, said method comprises the steps of making an incision in a knee portion of one leg of a patient, cutting a bone in the one leg of the patient, said step of cutting a bone includes moving a cutting tool into engagement with the bone, moving a leading end portion of an endoscope through the incision to a position spaced from the incision, visually inspecting a portion of the knee portion of the one leg of the patient by viewing the portion of the knee portion of the one leg through the endoscope, moving an implant into the knee portion of the one leg of the patient, and connecting the implant with the bone after having performed said step of moving the implant into the knee portion of the one leg of the patient.

215. A method as set forth in claim 214 wherein said step of inspecting a portion of the knee portion of the one leg of the patient includes viewing the implant through the endoscope.

216. A method as set forth in claim 214 wherein said step of inspecting a portion of the one leg of the patient is at least partially performed prior to performance of said step of connecting the implant with the bone.

217. A method as set forth in claim 214 further including the step of moving a lower portion of the one leg of the patient, said step of inspecting a portion of the knee portion of the one leg of the patient is at least partially performed during movement of the lower portion of the one leg of the patient.

218. A method as set forth in claim 214 wherein said step of making an incision in the knee portion of the one leg of the patient includes making the incision adjacent to a medial edge portion of a patella in the knee portion of the one leg of the patient, said step of moving the leading end portion of the endoscope to a position spaced from the incision includes moving the leading end portion of the endoscope along a path which is at least partially disposed medially of a bone in the one leg of the patient.

219. A method as set forth in claim 214 wherein said step of inspecting a portion of the one leg of the patient is at least partially performed prior to performance of said step of cutting the bone.

220. A method as set forth in claim 214 wherein said step of making the incision in the knee portion of the one leg of the patient is performed with a lower portion of the one leg suspended from the upper portion of the one leg, said step of cutting the bone in the one leg of the patient is performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg.

221. A method as set forth in claim 220 further including the steps of moving the endoscope out of the incision in the knee portion of the one leg of the patient and closing the incision in the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is suspended from the upper portion of the one leg of the patient.

222. A method as set forth in claim 214 further including the steps of positioning a first portion of a sterile drape system over the patient with at least the knee portion of the one leg of the patient exposed, connecting a second portion of the sterile drape system with a body of a surgeon who is to perform surgery on the knee portion of the one leg of the patient with the second portion of the sterile drape extending beneath the one leg of the patient and with the second portion of the sterile drape system connected with the first portion of the sterile drape system.

223. A method as set forth in claim 214 further including the step of connecting the cutting tool with a robot, said step of cutting the bone includes moving the cutting tool relative to the bone under the influence of force transmitted to the cutting tool from the robot.

225. A method as set forth in claim 224 further including the step of moving a patella in the knee portion of the one leg of the patient from a normal position of the patella to an offset position with an inner side of the patella facing inward.

226. A method as set forth in claim 224 wherein said step of making an incision includes making an incision which has a length of between about seven and about thirteen centimeters.

227. A method as set forth in claim 224 further including the step of expanding the incision by applying force against opposite edges of the incision, said step of moving a guide member into the incision is at least partially performed while the incision is expanded.

228. A method as set forth in claim 224 further including the step of moving an endoscope through the incision to a portion of the knee portion opposite from the incision and inspecting the portion of the knee portion opposite from the incision through the endoscope.

229. A method as set forth in claim 224 wherein said step of visually inspecting the portion of the knee portion opposite from the endoscope includes viewing the implant through the endoscope.

230. A method as set forth in claim 224 wherein said step of inspecting a portion of the knee portion opposite from the incision is at least partially performed prior to performance of said step of positioning an implant in engagement with the femur in the one leg of the patient.

231. A method as set forth in claim 224 wherein said steps of making an incision in a knee portion of the one leg of the patient, moving a guide member into the incision, positioning the guide member on the femur, cutting the femur, and positioning an implant in engagement with the femur are performed with a lower portion of the one leg of the patient extending downward from an upper portion of the one leg and with a foot connected with the lower portion of the one leg of the patient below the support surface.

232. A method as set forth in claim 224 wherein said step of cutting the femur includes forming a surface on the femur which has a dimension in a direction parallel to a central axis of the guide surface which is greater than the distance between the opposite ends of the guide member.

234. A method as set forth in claim 233 further including the steps of moving a guide member having opposite ends which are spaced apart by a distance which is less than two thirds (⅔

) of a distance across an end portion of the one bone at a location where the distance across the end portion of the one bone is a maximum, and positioning the guide member on the end portion of the one bone while the joint is flexed, said step of cutting the one bone at the joint includes moving the cutting tool along a guide surface on the guide member and cutting bone to form a cut surface which extends across the end portion of the one bone and has a dimension extending parallel to a longitudinal central axis of the guide surface which is greater than the length of the guide surface.

235. A method as set forth in claim 233 wherein said step of inserting at least one retractor into the incision while the joint is flexed and holding back a margin of the incision with the one retractor to increase exposure of the one bone at the joint while the joint is flexed.

236. A method as set forth in claim 233 further including the step of the steps of inserting a first retractor into the incision while the joint is flexed, inserting a second retractor into the incision while the joint is flexed, and expanding the incision while the joint is flexed by separating opposite margins of the incision under the influence of force applied to opposite margins of the incision by the first and second retractors.

237. A method as set forth in claim 236 further including the step of cutting the one bone at the joint with the cutting tool while the joint is flexed is at least partially performed while performing said step of expanding the incision.

238. A method as set forth in claim 233 further including the step of pivoting a first portion of the patient extending in a first direction from the joint sidewardly in a direction transverse to normal movement of the first portion of the patient during flexion and extension of the joint while the joint is flexed and after having performed said step of cutting the one bone at the joint.

239. A method as set forth in claim 238 further including the step of pivoting a first portion of the patient sidewardly is performed with the first portion of the patient suspended from a second portion of the patient which extends in a second direction from the joint.

240. A method as set forth in claim 233 further including the steps of rotating a first portion of the patient extending in a first direction from the joint about an axis extending along the first portion of the patient while the joint is flexed and after having performed said step of cutting the one bone at the joint.

241. A method as set forth in claim 233 further including the steps of positioning a guide member relative to the one bone while the joint is flexed, said step of cutting the one bone includes utilizing a guide surface on the member to position the cutting tool during making of an initial portion of a cut in the one bone, and completing the cut in the one bone while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the one bone.

242. A method as set forth in claim 233 wherein said step of positioning an implant in engagement with the one bone includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone, moving the second portion of the implant through the incision into engagement with the one bone, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone.

244. A method as set forth in claim 243 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes bonding of material of the first portion of the implant to material of the second portion of the implant.

245. A method as set forth in claim 243 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes mechanically interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

246. A method as set forth in claim 243 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes interconnecting the first and second portions of the implant with a member which extends between the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

247. A method as set forth in claim 243 wherein said step of cutting the one bone in the one leg of the patient is performed with a lower portion of the one leg suspended from an upper portion of the one leg.

249. A method as set forth in claim 248 wherein said step of supporting the patient on a support surface includes supporting the patient on the support surface with a lower portion of the one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the one leg of the patient is below the support surface, said steps of making an incision in the knee portion of the one leg and cutting the one bone in the one leg being performed with the foot connected with the one leg below the support surface.

250. A method as set forth in claim 248 wherein said steps of making an incision in a knee portion of the one leg and cutting the one bone in the one leg are performed with a lower portion of the one leg suspended from an upper portion of the one leg.

251. A method as set forth in claim 248 wherein said step of making an incision in a knee portion of the one leg of the patient includes making an incision adjacent to an edge portion of a patella in the one leg of the patient, said method further includes the steps of expanding the incision by applying force against opposite edge portions of the incision, and moving the patella from its normal position to an offset position with an inner side of the patella facing inward, said step of cutting the one bone being performed with the patella in a position offset from its normal position with an inner side of the patella facing inward.

252. A method as set forth in claim 248 further including steps of bending the knee portion of the one leg of the patient, generating images of the knee portion of the one leg of the patient with a lower portion of the one leg of the patient in a plurality of different positions relative to an upper portion of the one leg after performing said step of making an incision in the knee portion of the one leg, and, thereafter, closing the incision.

253. A method as set forth in claim 248 further including steps of supporting an upper portion of the one leg of the patient above the support surface with a leg support having a surface which is dispose beneath a posterior surface area on the upper portion of the one leg, said steps of making an incision in a knee portion of the one leg, cutting the one bone, and positioning an implant in engagement with the one bone being performed with a lower portion of the one leg extending downward from an upper portion of the one leg and a foot connected with the lower portion of the one leg below the support surface while the upper portion of the one leg is supported above the support surface by the leg support.

254. A method as set forth in claim 248 further including step of making an incision in a knee portion of the one leg of the patient includes making an incision in an anterior side of the knee portion of the one leg of the patient, said method further includes moving a leading end portion of an endoscope through the incision in the anterior side of the knee portion of the one leg of the patient to a posterior portion of the knee portion of the one leg of the patient, and visually inspecting the posterior portion of the knee portion of the one leg by viewing the posterior portion of the knee portion of the one leg through the endoscope.

255. A method as set forth in claim 248 wherein said step of positioning the implant in engagement with the one bone includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone, moving the second portion of the implant through the incision into engagement with the one bone, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone.

257. A method as set forth in claim 256 wherein the lower portion of the one leg of the patient is suspended from the upper portion of the one leg of the patient during performance of said steps of making an incision in the knee portion of the one leg of the patient, cutting the femur with the cutting tool, and closing the incision.

258. A method as set forth in claim 256 further including the step of expanding the incision by applying force against opposite edge portions of the incision while the upper portion of the one leg is supported above the support surface by the leg support and the foot connected with the one leg of the patient is below the support surface.

259. A method as set forth in claim 256 further including the steps of bending the knee portion of the one leg of the patient, and generating images of the knee portion of the one leg of the patient after performing said step of making an incision in the knee portion of the one leg of the patient and prior to performing said step of closing the incision.

260. A method as set forth in claim 256 further including the steps of moving a leading end portion of an endoscope through the incision, and visually inspecting a posterior portion of the knee portion of the one leg of the patient through the endoscope.

261. A method as set forth in claim 256 wherein said step of positioning an implant in engagement with the femur includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the femur, and interconnecting the first and second portions of the implant while they are disposed in engagement with the femur.

262. A method as set forth in claim 256 wherein said step of cutting the femur in the upper portion of the one leg of the patient includes utilizing the guide surface on the guide member to position the cutting tool during making of an initial portion of a cut in the femur, and completing the cut in the femur while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the femur.

263. A method as set forth in claim 256 further including the step of effecting relative movement between the incision and bones in the one leg of the patient by moving the lower portion of the one leg of the patient relative to the upper portion of the one leg of the patient while the upper portion of the one leg of the patient is supported above the support surface by the leg support and the foot connected with the one leg of the patient is below the support surface.

264. A method as set forth in claim 256 further including the step of providing an output signal which is a function of tension in a ligament extending between the femur and bones in a lower portion of the one leg of the patient.

265. A method as set forth in claim 256 further including the step of moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second positioning which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while the upper portion of the one leg is supported above the support surface by the leg support and the foot connected with the one leg of the patient is below the support surface, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

266. A method as set forth in claim 256 further including the step of cutting the patella in the knee portion of the one leg of the patient while the patella is disposed in the normal position relative to the knee portion of the one leg with an inner side of the patella facing inward.

268. A method as set forth in claim 267 wherein a lower portion of the one leg of the patient is suspended from an upper portion of the one leg and the patient during performance of said steps of making an incision in the knee portion of the one leg of the patient, and cutting the femur with the cutting tool.

269. A method as set forth in claim 267 further including the step of expanding the incision by applying force against opposite edge portions of the incision while a foot connected with the one leg of the patient is below the support surface.

270. A method as set forth in claim 267 further including the steps of bending the knee portion of the one leg of the patient, and generating images of the knee portion of the one leg of the patient after performing said step of making an incision in the knee portion of the one leg of the patient and prior to closing the incision.

271. A method as set forth in claim 267 further including the steps of moving a leading end portion of an endoscope through the incision, and visually inspecting a portion of the knee portion of the one leg of the patient through the endoscope.

272. A method as set forth in claim 267 wherein said step of positioning an implant in engagement with the one bone in the one leg of the patient includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone.

273. A method as set forth in claim 267 further including the step of effecting relative movement between the incision and bones in the one leg of the patient by moving the lower portion of the one leg of the patient relative to the upper portion of the one leg of the patient while a foot connected with the one leg of the patient is below the support surface.

274. A method as set forth in claim 267 further including the step of providing an output signal which is a function of tension in a ligament extending between bones in the one leg of the patient.

275. A method as set forth in claim 267 further including the step of moving a lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second positioning which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while a foot connected with the one leg of the patient is below the support surface, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

276. A method as set forth in claim 267 further including the step of cutting the patella in the knee portion of the one leg of the patient while the patella is disposed in a normal position relative to the knee portion of the one leg with an inner side of the patella facing inward.

278. A method as set forth in claim 277 further including the step of positioning a guide adjacent to an edge portion of the patella while the patella is disposed in the normal position relative to the knee portion of the one leg, said step of cutting the patella includes moving a cutting tool along a guide surface on the guide.

279. A method as set forth in claim 277 wherein a lower portion of the one leg of the patient is suspended from an upper portion of the one leg and the patient during performance of said steps of making an incision in the knee portion of the one leg of the patient, and cutting the one bone with the cutting tool.

280. A method as set forth in claim 277 further including the step of expanding the incision by applying force against opposite edge portions of the incision while a foot connected with the one leg of the patient is below the support surface.

281. A method as set forth in claim 277 further including the steps of bending the knee portion of the one leg of the patient, and generating images of the knee portion of the one leg of the patient after performing said step of making an incision in the knee portion of the one leg of the patient and prior to closing the incision.

282. A method as set forth in claim 277 further including the steps of moving a leading end portion of an endoscope through the incision, and visually inspecting a portion of the knee portion of the one leg of the patient through the endoscope.

283. A method as set forth in claim 277 wherein said step of positioning an implant in engagement with the one bone includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone.

284. A method as set forth in claim 277 wherein said step of cutting the one bone in one leg of the patient includes utilizing a guide surface on a guide member to position the cutting tool during making of an initial portion of a cut in the one bone, and completing the cut in the one bone while guiding a cutting tool with a surface formed during making of the initial portion of the cut in the one bone.

285. A method as set forth in claim 277 further including the step of effecting relative movement between the incision and bones in the one leg of the patient by moving a lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient while a foot connected with the one leg of the patient is below the support surface.

286. A method as set forth in claim 277 further including the step of providing an output signal which is a function of tension in a ligament extending between bones in the one leg of the patient.

287. A method as set forth in claim 277 further including the step of moving a lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second positioning which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while a foot connected with the one leg of the patient is below the support surface, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

289. A method as set forth in claim 288 wherein said step of cutting the patella includes making a cut which extends along inner side of the patella to separate at least a portion of the inner side of the patella from the remainder of the patella, said step of positioning the implant in engagement with the patella includes engaging a surface formed during cutting of the patella with the implant.

290. A method as set forth in claim 288 wherein said step of moving a guide through the incision into engagement with the patella includes moving a first guide element into engagement with the superior end portion of the patella and moving a second guide element into engagement with the inferior end portion of the patella, said step of moving the cutting tool relative to the guide surface includes moving the cutting tool along a portion of the guide which extends between the first and second guide elements.

291. A method as set forth in claim 288 further including the steps of cutting the femur in the one leg of the patient, and positioning a second implant in engagement with the femur in the one leg of the patient prior to performance of said step of closing the incision.

292. A method as set forth in claim 288 wherein a lower portion of the one leg of the patient is suspended from an upper portion of the one leg and the patient during performance of said steps of making an incision in the knee portion of the one leg of the patient, and cutting the patella with the cutting tool.

293. A method as set forth in claim 288 further including the step of expanding the incision by applying force against opposite edge portions of the incision while a foot connected with the one leg of the patient is below the support surface.

294. A method as set forth in claim 288 further including the steps of bending the knee portion of the one leg of the patient, and generating images of the knee portion of the one leg of the patient after performing said step of making an incision in the knee portion of the one leg of the patient and prior to closing the incision.

295. A method as set forth in claim 288 further including the steps of moving a leading end portion of an endoscope through the incision, and visually inspecting a portion of the knee portion of the one leg of the patient through the endoscope.

296. A method as set forth in claim 288 further including the step of effecting relative movement between the incision and bones in the one leg of the patient by moving the lower portion of the one leg of the patient relative to an upper portion of the one leg of the patient while a foot connected with the one leg of the patient is below the support surface.

297. A method as set forth in claim 288 further including the step of providing an output signal which is a function of tension in fibrous connective tissue extending between bones in the one leg of the patient.

298. A method as set forth in claim 288 further including the step of providing an output signal which is a function of tension in the fibrous connective tissue connected with at least one of the end portions of the patella.

299. A method as set forth in claim 288 further including the step of moving a lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is disposed on a first side of a reference plane and a second position in which the ankle portion of the one leg of the patient is disposed on a second side of the reference plane while a foot connected with the one leg of the patient is below the support surface, the reference plane extends through the knee portion of the one leg of the patient and extends perpendicular to a longitudinal central axis of the upper portion of the patient'"'"'s one leg.

224. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a guide member having opposite ends which are spaced apart by a distance which is less than two thirds (⅔

) of a distance between tips of lateral and medial epicondyles on a femur in an upper portion of the one leg of the patient into the incision, positioning the guide member on the femur in the one leg of the patient with opposite ends of the guide member substantially aligned with an axis through the lateral and medial epicondyles on the femur in the one leg of the patient, moving a cutting tool through the incision into engagement with a guide surface on the guide member, cutting the femur in the one leg of the patient with the cutting tool, said step of cutting the femur includes moving the cutting tool along the guide surface on the guide member, and positioning an implant in engagement with the femur in the one leg of the patient.

233. A method of performing surgery on a joint in a patient'"'"'s body, said method comprising the steps of flexing the joint, making an incision in body tissue which extends around the joint while the joint is flexed, said step of making an incision includes making an incision which has a length of less than thirteen centimeters, moving a cutting tool through the incision into engagement with at least one bone at the joint while the joint is flexed, cutting the one bone at the joint with the cutting tool while the joint is flexed, and positioning an implant in engagement with the one bone while the joint is flexed.

243. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a cutting tool through the incision into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, and positioning an implant in engagement with the one bone in the one leg of the patient, said step of positioning the implant in engagement with the one bone includes providing an implant having first and second portions which are separate from each other, moving the first portion of the implant through the incision into engagement with the one bone, moving the second portion of the implant through the incision into engagement with the one bone, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone.

248. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, positioning a guide member relative to one bone in the knee portion of the one leg of the patient, said step of positioning a guide member relative to the one bone includes moving a retainer member through skin on the one leg of the patient into the one bone to retain the guide member against movement relative to the one bone, moving a cutting tool through the incision into engagement with the one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, said step of cutting the one bone in the one leg of the patient includes moving the cutting tool along a guide surface on the guide member while the guide member is held against movement relative to the one bone by the retainer member extending through the skin on the one leg of the patient, and positioning an implant in engagement with the one bone in the one leg of the patient.

256. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, said step of supporting the patient on a support surface includes supporting an upper portion of the one leg of the patient above the support surface with a leg support having a surface which is disposed beneath a posterior surface area on the upper portion of the one leg with a lower portion of the one leg of the patient extending downward from the upper portion of the one leg so that a foot connected with the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the upper portion of the one leg is supported above the support surface by the leg support and the foot connected with the one leg of the patient is below the support surface, said step of making an incision in the knee portion of the one leg includes making an incision having a length of less than about thirteen centimeters, said step of making an incision includes making an incision adjacent to an edge portion of the patella in the knee portion of the one leg of the patient, moving the patella from its normal position to an offset position with an inner side of the patella facing inward, moving a guide member having opposite ends which are spaced apart by a distance which is less than a distance between lateral and medial epicondyles on a femur in the upper portion of the one leg of the patient into the incision, positioning the guide member on the femur in the one leg of the patient with opposite ends of the guide member substantially aligned with an axis through the lateral and medial epicondyles on the femur while the upper portion of the one leg is supported above the support surface by the leg support and the foot connected with the one leg of the patient is below the support surface, moving a cutting tool into engagement with the femur in the upper portion of the one leg of the patient, cutting the femur in the upper portion of the one leg of the patient with the cutting tool, said step of cutting the femur with the cutting tool includes moving the cutting tool along a guide surface on the guide member while the patella is offset from its normal position relative to the femur with the inner side of the patella facing inward, said step of cutting the femur with the cutting tool is performed with the upper portion of the one leg of the patient supported above the support surface by the leg support and with the foot connected with the one leg of the patient below the support surface, moving the cutting tool away from the femur, moving the guide member away from the femur, positioning an implant in engagement with the femur, and closing the incision while the upper portion of the one leg is supported above the support surface by the leg support and the foot connected with the one leg is below the support surface.

267. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, connecting a guide member with at least one bone in the leg of the patient, moving a cutting tool through the incision into engagement with the one bone in the one leg of the patient, moving the cutting tool along the guide surface on the guide member during making of an initial portion of a cut in the one bone, completing the cut in the one bone while guiding the cutting tool with a surface formed during making of the initial portion of the cut, and positioning an implant in engagement with the one bone in the one leg of the patient

277. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, positioning an implant in engagement with the one bone in the one leg of the patient, and cutting a patella in the knee portion of the one leg of the patient while the patella is disposed in a normal position relative to the knee portion of the one leg with an inner side of the patella facing inward, said step of cutting the patella includes making a cut to separate at least a portion of the inner side of the patella from the remainder of the patella.

288. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of one leg of the patient, moving at least a portion of a guide through the incision into engagement with a patella in the knee portion of the one leg of the patient, said step of moving a guide into engagement with the patella being performed while an inner side of the patella faces toward an end portion of the femur in the one leg of the patient and while the patella is at least partially held in position relative to the end portion of the femur by fibrous connective tissue connected with superior and inferior end portions of the patella, cutting the patella in the knee portion of the one leg of the patient while the inner side of the patella faces toward the end portion of the femur in the one leg of the patient and while the patella is at least partially held in position relative to the end portion of the femur by fibrous connective tissue connected with superior and inferior end portions of the patella, said step of cutting the patella includes moving a cutting tool relative to a guide surface on the guide while the cutting tool is disposed in engagement with the patella, positioning an implant in engagement with the patella in the knee portion of the one leg of the patient, and thereafter, closing the incision in the knee portion of the one leg of the patient with the implant disposed between the patella and the end portion of the femur and with the patella at least partially held in position relative to the end portion of the femur by fibrous connective tissue connected with superior and inferior end portions of the patella.

300. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, positioning a transducer between fibrous connective tissue and at least one bone in the one leg of the patient, bending the knee portion of the one leg of the patient with the transducer between the fibrous connective tissue and at least one bone in the one leg of the patient, and providing an output signal which varies as a function of variations in tension in the fibrous connective tissue during bending of the knee portion of the one leg of the patient.

301. A method as set forth in claim 300 wherein said step of bending the knee portion of the one leg of the patient includes moving a foot connected with the one leg of the patient between a position in which the foot is below the support surface and a position in which at least a portion of the foot is disposed above the support surface.

302. A method as set forth in claim 301 further including the step of moving a cutting tool through the incision into engagement with a first bone in the one leg of the patient, cutting the first bone in the one leg of the patient with the cutting tool, and positioning an implant in engagement with the first bone in the one leg of the patient.

303. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a leading end portion of a cannula into the incision, moving at least a portion of a cutting tool through the cannula into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool after moving at least a portion of the cutting tool through the cannula, moving an implant through the cannula, and positioning the implant in engagement with the one bone in the one leg of the patient.

304. A method as set forth in claim 303 wherein said step of moving an implant through the cannula includes moving a first portion of the implant through the cannula into engagement with the one bone in the one leg of the patient, moving a second portion of the implant through the cannula into engagement with the one bone in the one leg of the patient, and interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg.

305. A method as set forth in claim 304 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes bonding of material of the first portion of the implant to material of the second portion of the implant.

306. A method as set forth in claim 304 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes mechanically interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

307. A method as set forth in claim 304 wherein said step of interconnecting the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient includes interconnecting the first and second portions of the implant with a member which extends between the first and second portions of the implant while they are disposed in engagement with the one bone in the one leg of the patient.

308. A method as set forth in claim 303 wherein said step of cutting the one bone in the one leg of the patient is performed with a lower portion of the one leg suspended from an upper portion of the one leg.

309. A method as set forth in claim 303 further including the step of expanding the incision by applying force against opposite edge portions of the incision with the leading end portion of the cannula.

310. A method as set forth in claim 303 wherein said step of cutting the bone in the one leg of the patient with the cutting tool is performed with a foot connected with the one leg of the patient below the support surface.

311. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg is below the support surface, cutting an end portion of a femur in the upper portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, effecting relative movement between the incision and bones in the one leg of the patient while the foot connected with the lower portion of the one leg of the patient is below the support surface by moving the lower portion of the one leg of the patient between a first position in which an ankle portion of the one leg of the patient is at least partially disposed on a first side of a reference plane which extends through the knee portion of the one leg and extends perpendicular to a longitudinal central axis of the upper portion of the one leg and a second position in which the ankle portion of the one leg is disposed on a second side of the reference plane which extends through the knee portion of the one leg and extends perpendicular to the longitudinal central axis of the upper portion of the one leg, said knee portion of said one leg being flexed to a first extent when the lower portion of the one leg is in the first position and being flexed to a second extent when the lower portion of the one leg is in the second position, said second extent of flexion of said knee portion of said one leg being greater than said first extent of flexion of said knee portion of said one leg, and cutting an end portion of a tibia in the lower portion of the one leg of the patient while the lower portion of the one leg of the patient is in the second position.

312. A method as set forth in claim 311 further including the step of cutting a patella in the knee portion of the one leg of the patient while the inner side of the patella faces toward the end portion of the femur in the one leg of the patient and while the patella is at least partially held in position relative to the end portion of the femur by fibrous connective tissue connected with superior and inferior end portions of the patella.

313. A method as set forth in claim 312 further including the steps of connecting a first implant with the end portion of the femur after cutting the end portion of the femur, connecting a second implant with the end portion of the tibia after cutting the end portion of the tibia, and connecting a third implant with the patella after cutting the patella.

314. A method as set forth in claim 313 further including the step of moving the patella from its normal position relative to the end portion of the femur to an offset position with an inner side of the patella facing inward, said steps of cutting the end portion of the femur, cutting the end portion of the tibia, connecting a first implant with the end portion of the femur, and connecting a second implant with the end portion of the tibia being performed with the patella in the offset position.

315. A method as set forth in claim 314 further including the step of moving the patella from the offset position back to the normal position after performing said steps of cutting the end portion of the femur, cutting the end portion of the tibia, connecting a first implant with the end portion of the femur, and connecting the second implant with the end portion of the tibia, said steps of cutting the patella and connecting a third implant with the patella being performed with the patella in its normal position.

316. A method as set forth in claim 311 further including the step of supporting the upper portion of the one leg of the patient above the support surface with a leg support which is disposed beneath a posterior surface area on the upper portion of the one leg, said steps of making an incision in the knee portion of the one leg, cutting an end portion of the femur, and cutting an end portion of the tibia being performed with the upper portion of the one leg supported above the support surface by the leg support.

317. A method as set forth in claim 311 wherein said step of cutting the femur includes moving a cutting tool along a guide surface on a guide member during making of an initial portion of a cut in the femur, and completing the cut in the femur while guiding the cutting tool with a surface formed during making of the initial apportion of the cut in the femur, said step of cutting the tibia includes moving a cutting tool along a guide surface on a guide member during making of an initial portion of a cut in the tibia, and completing the cut in the tibia while guiding the cutting tool with a surface formed during making of the initial portion of the cut in the tibia.

318. A method as set forth in claim 311 further including the step of positioning a guide member relative to the femur in the one leg of the patient, said step of positioning a guide member relative to the femur in the one leg of the patient includes moving a retainer member through skin on the upper portion of the one leg of the patient into the femur to retain the guide member against movement relative to the femur.

319. A method as set forth in claim 311 further including the step of positioning a guide member relative to the tibia in the one leg of the patient, said step of positioning the guide member relative to the tibia in the one leg of the patient includes moving a retainer member through the skin in the lower portion of the one leg of the patient into the tibia to retain the guide member against movement relative to the tibia.

320. A method as set forth in claim 311 further including the steps of positioning a transducer between fibrous connective tissue and at least one bone in the one leg of the patient, bending the knee portion of the one leg of the patient, and providing an output signal which varies as a function of variations in tension in fibrous connective tissue during bending of the knee portion of the one leg of the patient.

321. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, moving a cutting tool into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, positioning an implant in engagement with the one bone in the one leg of the patient, and, thereafter, comparing tension forces in fibrous connective tissue disposed on opposite sides of bones in the knee portion of the one leg of the patient, said step of comparing tension forces includes positioning a first transducer on a first side of the knee portion of the one leg of the patient, positioning a second transducer on a second side of the knee portion of the one leg of the patient, bending the knee portion of the one leg of the patient with the first transducer on the first side of the knee portion of the one leg of the patient and with the second transducer on the second side of the knee portion of the one leg of the patient, providing an output signal from the first transducer which varies as a function of variations in tension forces in fibrous connective tissue on the first side of the knee portion of the one leg of the patient during performance of said step of bending the knee portion of the one leg of the patient, and providing an output signal from the second transducer which varies as a function of variations in tension forces in fibrous connective tissue on the second side of the knee portion of the one leg of the patient during performance of said step of bending the one leg of the patient.

322. A method as set forth in claim 321 wherein said step of bending the knee portion of the one leg of the patient is at least partially performed with a foot connected with a lower portion of the one leg of the patient below the support surface.

323. A method as set forth in claim 321 further including the steps of comparing the output signals from the first and second transducers and adjusting tension in the fibrous connective tissue on the first side of the knee portion of the one leg of the patient when the tension in the fibrous connective tissue on one of the first and second sides of the knee portion of the one leg of the patient is excessive.

324. A method as set forth in claim 321 wherein said steps of making an incision in a knee portion of the one leg of the patient and cutting the one bone in the one leg of the patient are at least partially performed with a lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

325. A method as set forth in claim 321 further including the step of inspecting portions of the knee portion of the one leg of the patient which are remote from the incision during performance of said step of bending the knee portion of the one leg of the patient, said step of inspecting a portion of the knee portion of the one leg of the patient includes viewing tissue in the knee portion of the one leg of the patient through an endoscope.

326. A method as set forth in claim 321 further including the step of generating images of the knee portion of the one leg of the patient during performance of said step of bending the knee portion of the one leg of the patient.

327. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, positioning a tibial alignment shaft along a longitudinal axis of a tibia in a lower portion of the one leg of the patient, moving a cutting tool into engagement with a guide surface connected with the tibial alignment shaft, cutting the tibia in the lower portion of the one leg of the patient with the cutting tool, said step of cutting the tibia is at least partially performed with the tibial alignment shaft extending along the longitudinal axis of the tibia and includes moving the cutting tool along the guide surface, and positioning an implant in engagement with the tibia in the one leg of the patient.

328. A method as set forth in claim 327 further including the step of moving the guide surface along the tibial alignment shaft under the influence of force transmitted from a stylus disposed in engagement with a proximal end of the tibia in the lower portion of the one leg of the patient to a guide member on which the guide surface is disposed.

329. A method as set forth in claim 327 further including the step of connecting a guide member upon which the guide surface is disposed to the tibia in the lower portion of the one leg of the patient with a single pin.

330. A method as set forth in claim 327 further including the step of at least partially retaining a guide member upon which the guide surface is disposed against movement relative to the tibia in the lower portion of the one leg of the patient under the influence of force transmitted between the guide member and the tibial alignment shaft during performance of said step of cutting the tibia in the lower portion of the one leg of the patient.

331. A method as set forth in claim 327 wherein said step of positioning a tibial alignment shaft along a longitudinal axis of a tibia in the lower portion of the one leg of the patient includes positioning the alignment shaft adjacent to an outer surface of the lower portion of the one leg of the patient.

332. A method as set forth in claim 327 wherein said step of positioning a tibial alignment shaft along a longitudinal axis of a tibia in a lower portion of the one leg of the patient includes positioning at last a portion of the tibial alignment shaft in a marrow cavity of the tibia.

333. A method as set forth in claim 327 wherein said steps of positioning the tibial alignment shaft along the longitudinal axis of the tibia in the lower portion of the one leg of the patient and cutting the tibia are performed with a foot connected with the lower portion of the one leg of the patient below the support surface.

334. A method as set forth in claim 327 wherein said step of positioning the tibial alignment shaft along a longitudinal axis of the tibia in the lower portion of the one leg of the patient includes connecting a lower end portion of the tibial alignment shaft with a lower end portion of the tibia.

335. A method as set forth in claim 327 wherein said steps of positioning the tibial alignment shaft along the longitudinal axis of the tibia in the lower portion of the one leg of the patient and cutting the tibia are performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

336. A method as set forth in claim 327 wherein said step of cutting the tibia in the lower portion of the one leg of the patient with the cutting tool includes moving the cutting tool along the guide surface during making of an initial portion of a cut in the tibia and completing the cut in the tibia while guiding the cutting tool with a surface formed during making of the initial portion of the cut.

339. A method as set forth in claim 338 further including the step of transmitting force between the new bone which at least partially fills the recess in the first bone and the articular surface on the second bone.

340. A method as set forth in claim 338 further including the step of effecting sliding movement between the new bone which at least partially fills the recess in the first bone and the articular surface on the second bone during flexion of the patient'"'"'s knee.

341. A method as set forth in claim 338 further including the step of transmitting force between bone which extends around the recess in the first bone and the articular surface on the second bone.

342. A method as set forth in claim 338 wherein said step of positioning an implant containing bone growth promoting materials in the recess in the first bone is performed with a lower portion of the one leg of the patient extending downward from an upper portion of the one leg and a foot connected with the lower portion of the one leg below the support surface.

344. A method as set forth in claim 343 wherein said step of cutting away a portion of the articular surface on the first bone to form a recess in the first bone includes forming the recess with a substantially uniform depth.

346. A method as set forth in claim 343 wherein said step of positioning an implant in the recess in the first bone is performed with a lower portion of the one leg of the patient extending downward from an upper portion of the one leg and a foot connected with the lower portion of the one leg below the support surface.

348. A method as set forth in claim 347 wherein the joint is a knee joint in one leg of the patient.

350. A method as set forth in claim 349 wherein said step of moving an expandable device into a portion of a patient includes moving the expandable device into a knee portion of the patient.

354. A method as set forth in claim 353 wherein said steps of making an incision in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

355. A method as set forth in claim 353 wherein said steps of making an incision in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with a hip connected with the one leg of the patient hyperflexed.

356. A method as set forth in claim 353 wherein said step of directing light through the incision onto the one bone in the knee portion of the one leg of the patient includes projecting a hologram onto the one bone in the knee portion of the one leg of the patient.

357. A method as set forth in claim 353 wherein said step of directing light through the incision onto the one bone in the knee portion of the one leg of the patient includes directing a beam of light through the incision onto the one bone, said method further includes moving the cutting tool along the beam of light into engagement with the one bone in the one leg of the patient.

359. A method as set forth in claim 358 wherein said step of directing light through the incision onto the bone includes projecting a three dimensional image onto the bone.

360. A method as set forth in claim 358 wherein said step of directing light through the incision onto the bone includes directing a beam of light through the incision onto the bone, said method further includes moving a cutting tool along the beam of light into engagement with bone.

362. A method as set forth in claim 361 wherein said steps of making first and second incisions in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

363. A method as set forth in claim 361 wherein said steps of making first and second incisions in the knee portion of the one leg and cutting the one bone in the one leg of the patient are at least partially performed with a hip connected with the one leg of the patient hyperflexed.

365. A method as set forth in claim 364 wherein said step of bending the knee portion of the one leg of the patient includes moving a foot connected with the one leg of the patient between a position in which the foot is below the support surface and a position in which at least a portion of the foot is disposed above the support surface.

366. A method as set forth in claim 364 further including the step of moving a cutting tool through the incision into engagement with a first bone in the one leg of the patient, cutting the first bone in the one leg of the patient with the cutting tool, and positioning an implant in engagement with the first bone in the one leg of the patient.

368. A method as set forth in claim 367 wherein said steps of making an incision in the knee portion of the one leg is at least partially performed with the lower portion of the one leg of the patient suspended from the upper portion of the one leg of the patient.

369. A method as set forth in claim 367 wherein said step of making an incision in the knee portion of the one leg is at least partially performed with a hip connected with the one leg of the patient hyperflexed.

371. A method as set forth in claim 370 further including the step of moving the patella to an offset position with an inner side of the patella facing inward prior to performing said step of cutting the femur.

337. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the lower portion of the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, expanding the incision by applying force against opposite edge portions of the incision, moving a patella in the knee portion of the one leg from its normal position to an offset position with an inner side of the patella facing inward, cutting a distal end portion of a femur in the upper portion of the one leg of the patient while the patella is in the offset position with the inner side of the patella facing inward and while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, moving a proximal end portion of a tibia in the lower portion of the one leg of the patient in an anterior direction from a first position to a second position while the patella is in the offset position with the inner side of the patella facing inward and while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, cutting the proximal end portion of the tibia while the proximal end portion of the tibia is in the second position and while the patella is in the offset position with the inner side of the patella facing inward and while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, positioning a first implant on the distal end portion of the femur in the upper portion of the one leg of the patient while the patella is in the offset position with the inner side of the patella facing inward and while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, positioning a second implant on the proximal end portion of the tibia in the lower portion of the one leg of the patient while the patella is in the offset position with the inner side of the patella facing inward and while the lower portion of the one leg of the patient is extending downward form the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, moving the patella from the offset position back to the normal position, cutting the patella, positioning a third implant on the patella, and closing the incision while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

338. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of one leg of the patient, moving a cutting tool into engagement with an articular surface on a first bone which cooperates with an articular surface on a second bone, cutting away a portion of the articular surface on the first bone with the cutting tool to form a recess in the first bone, positioning an implant containing bone growth promoting materials in the recess in the first bone, closing the incision in the knee portion of the one leg of the patient, and growing bone from the first bone into the implant to at least partially fill the recess in the first bone with new bone growth.

343. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of one leg of the patient, moving a cutting tool into engagement with an articular surface on a first bone which cooperates with an articular surface on a second bone, cutting away a portion of the articular surface on the first bone with the cutting tool to form a recess in the first bone, positioning an implant in the recess in the first bone, closing the incision in the knee portion of the one leg of the patient, and transmitting force between the implant and the articular surface on the second bone, and transmitting force between bone which extends around the recess in the first bone and the articular surface on the second bone.

345. A method as et forth in clam 343 wherein said step of cutting away a portion of the articular surface on the first bone with the cutting tool includes controlling a depth of cut in the first bone and a configuration of the recess with a guide which engages the cutting tool.

347. A method of performing surgery on a patient, said method comprising the steps of providing an expandable device made of a biodegradable material, making an incision in a portion of the patient adjacent to a joint, inserting the expandable device made of biodegradable material through the incision into the portion of the patient adjacent to the joint, expanding the expandable device made of biodegradable material under the influence of fluid pressure to apply force against body tissue, and closing the incision with the expandable device in the portion of the patient adjacent to the joint.

349. A method of performing surgery on a patient, said method comprising the steps of moving an expandable device into a portion of a patient, stretching body tissue in the portion of the patient by expanding the expandable device, and, thereafter making an incision in the stretched body tissue.

351. A method of performing surgery on a patient, said method comprising the steps of making an incision in body tissue disposed adjacent to a bone in a portion of a patient'"'"'s body, forming a recess in the bone in the patient'"'"'s body, moving an implant containing bone growth promoting material through the incision into the recess in the bone, and growing new bone from the bone in the patient'"'"'s body into the implant.

352. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of positioning an expandable device in a knee portion of one leg of the patient, stretching body tissue in the knee portion of the one leg of the patient by expanding the expandable device in a knee portion of one leg of the patient, thereafter, making an incision in body tissue stretched by expanding the expandable device, moving a cutting tool through the incision into engagement with at least one bone in the knee portion of the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool, and moving an implant into engagement with the one bone in the knee portion of the one leg of the patient.

353. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the lower portion of the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, directing light through the incision onto at least one bone in the knee portion of the one leg of the patient, cutting the one bone in the one leg of the patient with a cutting tool at a location indicated by the light directed onto the bone while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and moving an implant into engagement with the one bone in the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

358. A method of performing surgery on a patient, said method comprising the steps of making an incision in a portion of the patient adjacent to a bone, directing light through the incision onto the bone, and cutting the bone at a location indicated by the light directed onto the bone.

361. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the lower portion of the one leg of the patient is below the support surface, making first and second incisions in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, moving a cutting tool through the first incision in the knee portion of the one leg of the patient into engagement with at least one bone in the one leg of the patient, cutting the one bone in the one leg of the patient with the cutting tool while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, and moving an implant through the second incision in the knee portion of the one leg of the patient into engagement with the one bone in the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface.

364. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface, making an incision in a knee portion of the one leg of the patient, positioning a transducer between a patella and a femur in the one leg of the patient, bending the knee portion of the one leg of the patient with the transducer between patella and femur in the one leg of the patient, and providing an output signal which varies as a function of variations in force transmitted between the patella and femur during bending of the knee portion of the one leg of the patient.

367. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of supporting the patient on a support surface with a lower portion of at least one leg of the patient extending downward from an upper portion of the one leg of the patient so that a foot connected with the lower portion of the one leg of the patient is below the support surface, making an incision in a knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, positioning a first transducer between a medial portion of a patella and a distal end portion of a femur in the one leg of the patient, positioning a second transducer between a lateral portion of the patella and the distal end portion of a femur in the one leg of the patient, bending the knee portion of the one leg of the patient while the lower portion of the one leg of the patient is extending downward from the upper portion of the one leg of the patient and while the foot connected with the lower portion of the one leg of the patient is below the support surface, providing from the first transducer a first output signal which varies as a function of variations in force transmitted between the medial portion of the patella and the distal end portion of the femur in the one leg of the patient during bending of the knee portion of the one leg of the patient, and providing from the second transducer a second output signal which varies as a function of variations in force transmitted between the lateral portion of the patella and the distal end portion of the femur in the one leg of the patient.

370. A method of performing surgery on a patient'"'"'s knee, said method comprising the steps of making an incision in a knee portion of one leg of the patient, cutting a patella in the knee portion of the one leg, cutting a tibia in the knee portion of the one leg after cutting the patella, cutting a femur in the knee portion of the one leg after cutting the patella and after cutting the tibia, and positioning at least one implant in the knee portion of the one leg of the patient.