Method of preparing a femur and tibia in knee arthroplasty

1. A method of preparing a femur and tibia in surgery on a knee joint using a navigation system and a robotic system comprising a base, a plurality of arms movable relative to the base, and a cutting tool coupled to the plurality of arms so that the cutting tool is capable of movement in at least five degrees of freedom, said method comprising the steps of:

arranging the navigation system to track movement of the femur and tibia during the surgery;

cutting away material from the femur with the cutting tool of the robotic system and without the use of physical resection guides wherein the navigation system cooperates with the robotic system to provide information associated with a position of the femur to the robotic system; and

cutting away material from the tibia with the cutting tool of the robotic system and without the use of physical resection guides wherein the navigation system cooperates with the robotic system to provide information associated with a position of the tibia to the robotic system,

wherein the navigation system enables separate tracking of the femur and tibia so that the positions of the femur and tibia can be determined when the femur and tibia move during the surgery.

2. The method as set forth in claim 1 wherein cutting away material from the femur includes cutting away material from one of a medial and lateral condyle of the femur with the cutting tool of the robotic system and without the use of physical resection guides.

3. The method as set forth in claim 2 including:

affixing a first implant member to the one condyle of the femur with the first implant member including a first articulating surface, wherein the other of the medial and lateral condyles is not provided with an affixed articulating surface; and

affixing a second implant member to the tibia.

4. The method as set forth in claim 3 including affixing a third implant member to a trochlear section of the femur to replace cut away material from the femur, the third implant member including an articulating surface.

5. The method as set forth in claim 4 wherein cutting away material from the femur includes cutting away material from the trochlear section of the femur so that a bridge of bone remains on the femur between the trochlear section and the one condyle.

6. The method as set forth in claim 5 wherein the first and third implant members are separated by the bridge of bone when affixed to the femur.

7. The method as set forth in claim 3 wherein cutting away material from the femur includes forming a recess in the one condyle of the femur with the cutting tool of the robotic system and without the use of physical resection guides such that the recess is peripherally surrounded by naturally occurring bone.

8. The method as set forth in claim 7 including positioning the first implant member in the recess formed in the one condyle of the femur.

9. The method as set forth in claim 8 wherein cutting away material from the tibia includes forming a recess in the tibia with the cutting tool of the robotic system and without the use of physical resection guides such that the recess is peripherally surrounded by naturally occurring bone.

10. The method as set forth in claim 9 including positioning the second implant member in the recess formed in the tibia opposite the first implant member.

11. The method as set forth in claim 1 including:

forming a recess in one of the femur or tibia with the cutting tool of the robotic system and without the use of physical resection guides such that the recess is peripherally surrounded by naturally occurring bone; and

positioning a first implant member in the recess.

12. The method as set forth in claim 1 wherein cutting away material from the femur includes cutting away material from only one of a medial and lateral condyle without cutting away material from the other of the medial and lateral condyles.

13. The method as set forth in claim 1 including making a minimally invasive incision to access the knee joint wherein the minimally invasive incision has a length that does not exceed thirteen centimeters.

14. The method as set forth in claim 1 including:

displacing a patella from a normal position to an offset position with an articulating surface of the patella facing the femur; and

cutting an articulating surface of the femur while maintaining the patella in the offset position with the articulating surface of the patella facing the femur.

15. The method as set forth in claim 1 including obtaining images of the knee joint and transmitting the images to a control unit.

16. The method as set forth in claim 15 wherein obtaining the images of the knee joint includes generating images of the knee joint during movement of a lower portion of a leg relative to an upper portion of the leg.

17. The method as set forth in claim 15 including displaying the transmitted images on a display for viewing during the surgery.

18. The method as set forth in claim 17 wherein displaying the transmitted images includes displaying relative movement between a distal end portion of the femur and a proximal end portion of the tibia.

19. The method as set forth in claim 1 including moving the tibia relative to the femur to display relative movement between a distal end portion of the femur and a proximal end portion of the tibia on a display before cutting away material from the femur and tibia.

20. The method as set forth in claim 19 including moving the tibia relative to the femur to display relative movement of the distal end portion of the femur and the proximal end portion of the tibia on the display after cutting away material from the femur and tibia.

21. The method as set forth in claim 1 including displaying a relationship between a first implant member and a second implant member on a display to evaluate the relationship between the first implant member and the second implant member.

22. The method as set forth in claim 1 including:

affixing a first implant member to the femur;

affixing a second implant member to the tibia; and

moving the tibia relative to the femur to display relative movement between the first implant member and the second implant member on a display after affixing the first implant member to the femur and affixing the second implant member to the tibia.

23. The method as set forth in claim 1 wherein cutting away material from the femur and tibia includes cutting away material from the femur and tibia while preserving at least a portion of a ligament of the knee joint.

24. The method as set forth in claim 1 wherein arranging the navigation system to track movement of the femur and tibia during the surgery includes attaching a first plurality of locating devices to the femur and attaching a second plurality of locating device to the tibia.

25. The method as set forth in claim 1 wherein arranging the navigation system to track movement of the femur and tibia during the surgery includes:

attaching a first plurality of emitters to the femur; and

attaching a second plurality of emitters to the tibia,

wherein the navigation system is an optical navigation system.

26. The method as set forth in claim 1 wherein arranging the navigation system to track movement of the femur and tibia during the surgery includes:

attaching a first plurality of reflectors to the femur; and

attaching a second plurality of reflectors to the tibia,

wherein the navigation system is an optical navigation system.

27. The method as set forth in claim 1 including moving the cutting tool relative to the femur and tibia wherein such movement includes one of user-controlled movement or robotically-controlled movement.

28. A method of preparing a femur and tibia in surgery on a knee joint using a navigation system and a robotic system comprising a base, a plurality of arms movable relative to the base, and a cutting tool coupled to the plurality of arms so that the cutting tool is capable of movement in at least five degrees of freedom, said method comprising the steps of:

arranging the navigation system to track movement of the femur and tibia during the surgery wherein the navigation system cooperates with the robotic system to provide information associated with positions of the femur and tibia to the robotic system;

cutting away material from the femur with the cutting tool of the robotic system using a non-physical femur cutting guide and without the use of physical resection guides; and

cutting away material from the tibia with the cutting tool of the robotic system using a non-physical tibia cutting guide and without the use of physical resection guides,

wherein the non-physical femur and tibia cutting guides define target shapes for the femur and tibia corresponding to desired femoral and tibial implant components to guide the cutting of material from the femur and tibia,

wherein the navigation system enables separate tracking of the femur and tibia so that the positions of the femur and tibia can be determined when the femur and tibia move during the surgery.

29. A method of preparing a femur and tibia in surgery on a knee joint using a navigation system comprising a first plurality of locating devices and a second plurality of locating devices and a robotic system comprising a base, a plurality of arms movable relative to the base, and a cutting tool coupled to the plurality of arms so that the cutting tool is capable of movement in at least five degrees of freedom, said method comprising the steps of:

attaching the first plurality of locating devices to the femur;

attaching the second plurality of locating devices to the tibia;

moving the cutting tool relative to the femur and tibia during the surgery;

cutting away material from the femur and tibia with the cutting tool of the robotic system and without the use of physical resection guides;

affixing a first member of a knee implant to one of a medial and lateral condyle of the femur to replace at least a portion of the material cut away from the femur, the first member including a first articulating surface and wherein the other of the medial and lateral condyles is not provided with an affixed articulating surface;

affixing a second member of the knee implant to the tibia opposite the first member to replace at least a portion of the material cut away from the tibia; and

moving the tibia relative to the femur after affixing the first and second members in order to evaluate a relationship between the first and second members as represented on a display,

wherein attaching the first plurality of locating devices to the femur and attaching the second plurality of locating devices to the tibia enables separate tracking of the femur and tibia so that the positions of the femur and tibia can be determined when the femur and tibia move during the surgery.

30. The method as set forth in claim 29 wherein moving the cutting tool relative to the femur and tibia during the surgery includes robotically-controlled movement.