Method and apparatus for resecting a distal femur and a proximal tibia in preparation for implementing a partial knee prosthesis

• US 20030216741A1
• Filed: 06/16/2003
• Published: 11/20/2003
• Est. Priority Date: 06/20/2001
• Status: Active Grant

• Current Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Hodorek, Robert A., Sanford, Adam H., Farling, Toby N., Williamson, Richard V., Saenger, Paul L., Price, Mark A.
• Granted Patent: US 7,285,122 B2
• Time in Patent Office: Days
• US Class Current: 606/87
• CPC Class Codes: A61B 17/154 for preparing bone for knee prosthesis
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/3895 unicompartimental

Abstract

A method of resecting a proximal tibia and distal femur for implanting a partial knee prosthesis uses a resecting kit which includes multiple spacers, each of which has a different spacing dimension. A surgeon selects the appropriate spacer with the amount of correction desired to align the patient'"'"'s leg and installs the spacer with the spacing dimension between the distal femur and proximal tibia which is to receive the partial knee prosthesis. The spacers have projecting stems, upon which a resector is installed. The resector is then aligned with the axis selected by the surgeon according to known methods, and is pinned to the femur and proximal tibia. A distal femoral cut is then made in the femur after which the resector is removed while leaving at least two of the pins in place, the pins being headless pins. A second resector is then installed on the pins to effect the required cut of the tibia. Additional cuts are made in the femur according to known procedures, and the femoral and tibial prostheses are then installed, according to known procedures.

Claims

1. Method of resecting a distal femur and a proximal tibia in preparation for implanting a partial knee prosthesis comprising the steps of installing a spacer having a fixed spacing dimension between the distal femur and proximal tibia to establish a gap of known width therebetween, said spacer having a projecting stem, mounting a resector on said stem, aligning said resector along a selected axis represented by an alignment rod extending from said resector, pinning said resector to both said distal femur and proximal tibia using multiple pins to prevent relative movement of said resector with respect to both said distal femur and proximal tibia, and using said resector to guide resection of one of said distal femur and proximal tibia.

2. Method of resecting as claimed in claim 1, wherein said method includes the step of selecting said spacer from a set of multiple spacers each having a different fixed spacing dimension.

3. Method of resecting as claimed in claim 1, wherein said fixed spacing dimension is defined by a bump on said spacer having a curved outer edge, said method including the step of rotating said spacer about said curved outer edge to permit said alignment rod to manipulated over obstructions.

4. Method of resecting as claimed in claim 3, wherein said proximal tibia terminates in a tibial plateau and said distal femur terminates in a condyle having a contoured distal surface defining said gap established by said spacer, said spacer having a flat surface opposite said bump, said method including the step of maintaining engagement of said flat surface with said area as said spacer is installed between said distal femur and proximal tibia.

5. Method of resecting as claimed in claim 1, wherein said spacer includes an arm extending axially from said stem, said fixed spacing dimension being defined by a bump extending from one side of said arm and a substantially flat surface on the other side of said arm opposite said bump, said method including the step of inserting said arm between said distal femur and proximal tibia while maintaining said flat surface in engagement with said distal femur and the bump in engagement with said proximal tibia.

6. Method of resecting as claimed in claim 5, wherein said bump is defined by a curved outer edge, said method including the step of rotating said spacer about said curved outer edge to permit said alignment rod to manipulated over obstructions.

7. Method of resecting as claimed in claim 5, wherein said proximal tibia terminates in a tibial plateau and said distal femur terminates in a condyle having a contoured distal surface defining said gap established by said spacer, said method including the step of maintaining said curved outer edge in engagement with said tibial plateau and said substantially flat surface in engagement with said contoured distal surface as said spacer is rotated about said curved outer edge.

8. Method of resecting as claimed in claim 1, wherein said proximal tibia terminates in a tibial plateau bounded by an anterior tibial rise, and said distal femur terminates in a condyle having a contoured distal surface defining said gap established by said spacer, said spacer including an arm extending axially from said stem, said fixed spacing dimension is defined by a bump extending from one side of said arm and a substantially flat surface on the other side of said arm opposite said bump, said step of installing said spacer including the steps of sliding the bump over the anterior tibial rise while maintaining said flat surface in engagement with said contoured distal surface.

9. Method of resecting as claimed in claim 8, wherein said arm defines a recess between said bump and said stem, said method including the step of permitting said anterior tibial rise to be received within said recess when the spacer is installed in said gap.

10. Method of resecting as claimed in claim 1, wherein said proximal tibia terminates in a tibial plateau bounded by an anterior tibial rise, and said distal femur terminates in a condyle having a contoured distal surface defining said gap established by said spacer, said spacer including an arm extending axially from said stem, said fixed spacing dimension being defined by a bump extending from one side of said arm and cooperating with said stem to define a recess therebetween, said method including the steps of engaging said bump with the tibial plateau, receiving said tibial rise in said recess, and engaging said arm with said contoured distal surface.

11. Method of resecting as claimed in claim 1, wherein said method includes the step of using a second resector to resect the other of said distal femur and proximal tibia.

12. Method of resecting as claimed in claim 11, wherein said method includes the steps of removing said first-mentioned resector from said pins after resecting said one of said distal femur and proximal tibia without changing the position of at least two of said pins, and installing said second resector on said pins, whereby the orientation of the cuts in the distal femur and proximal tibia relative to one another is maintained by the unchanged position of said pins.

13. Method of resecting as claimed in claim 12, wherein said second resector includes multiple sets of apertures for receiving said pins, whereby the distance between said cuts may be varied while maintaining the orientation of the cuts relative to one another.

14. Method of resecting as claimed in claim 1, wherein said resector is aligned by rotating said resector relative to said stem.

15. Method of resecting as claimed in claim 1, wherein said resector is aligned by pivoting the resector and the spacer as a unit, said resector being secured against rotation relative to said spacer.

16. Resecting kit for resecting a distal femur and a proximal tibia in preparation for implanting a partial knee prosthesis comprising a set of multiple spacers each having a different fixed spacing dimension whereby a spacer having the desired spacing dimension may be selected and installed between the distal femur and proximal tibia to establish a desired spacing therebetween, and resecting means mountable on said spacers for resecting said distal femur and proximal tibia.

17. Resecting kit as claimed in claim 16, wherein each of said spacers includes a projecting stem, said resecting means including a resector having an aperture pivotally mounted on said stem and multiple pins for securing said resector, said resector guiding resection of one of said distal femur and proximal tibia.

18. Resecting kit as claimed in claim 17, wherein said resecting means includes a second resector, said pins being headless to permit removal of said first-mentioned resector and installation of said second resector on said pins whereby the pins maintain the relative orientation of said resectors to permit resection of the other of said distal femur and proximal tibia.

19. Resecting kit as claimed in claim 16, wherein each of said spacers includes an arm extending between said proximal tibia and distal femur and a stem, said arm extending from said stem, said stem projecting from between said distal femur and proximal tibia, said resecting means being mounted on said stem.

20. Resecting kit as claimed in claim 19, wherein the arm of at least one of said spacers is a substantially flat blade having opposite substantially flat surfaces for engagement with said proximal tibia and distal femur respectively, said spacing dimension being the thickness of said blade between said substantially flat surfaces.

21. Resecting kit as claimed in claim 19, wherein the distal femur terminates in a pair of condyles and the proximal tibia terminates in a tibial plateau circumscribed in part by an anterior tibial rise, said arm including a bump on one side thereof for engagement with the tibial plateau and a surface opposite said bump for engagement with a corresponding one of said condyles.

22. Resecting kit as claimed in claim 21, wherein said surface opposite said bump is a substantially flat surface.

23. Resecting kit as claimed in claim 21, wherein said arm defines a recess between said stem and said bump, said recess receiving the anterior tibial rise when the spacer is installed with the bump engaging the tibial plateau.

24. Resecting kit as claimed in claim 23, wherein said stem terminates in a transverse surface defining one edge of said recess.

25. Resecting kit as claimed in claim 21, wherein said bump is defined by a curved outer edge to permit limited rotation of said spacer about said curved outer edge in response to movement of the stem in a sagittal plane.

26. Resecting kit as claimed in claim 25, wherein said bump includes transversely spaced keels to resist movement of the spacer in a lateral-medial plane when the spacer is installed between the one condyle and said tibial plateau.

27. Spacer for use in orthopedic surgery for establishing a known spacing dimension between contiguous ends of skeletal members, comprising a stem projecting from between said skeletal members when the spacer is installed therebetween and an arm extending from said stem, said arm having a bump on one side thereof and an engagement surface on the other side thereof, said spacing dimension being the distance between the engagement surface and the region of said bump of maximum distance from said engagement surface.

28. Spacer for use in orthopedic surgery as claimed in claim 27, wherein said bump is defined by a curved outer edge to permit limited rotation of said spacer about said curved outer edge in response to movement of the stem.

29. Spacer for use in orthopedic surgery as claimed in claim 27, wherein said bump includes transversely spaced keels to resist transverse movement of the spacer when the latter is installed between skeletal members.

30. Spacer for use in orthopedic surgery as claimed in claim 27, wherein said arm defines a recess between said stem and said bump.

31. Spacer for use in orthopedic surgery as claimed in claim 30, wherein said stem terminates in a transverse surface defining one edge of said recess.

32. Spacer for use in orthopedic surgery as claimed in claim 31, wherein said engagement surface opposite said bump is a substantially flat surface.

33. Spacer for use in orthopedic surgery as claimed in claim 29, wherein said stem is substantially cylindrical.

34. Spacer for use in orthopedic surgery as claimed in claim 29, wherein said stem includes flats on opposite sides of the stem.

35. Spacer kit for use in orthopedic surgery for establishing a known spacing dimension between contiguous ends of skeletal members, comprising multiple spacers each having a known spacing dimension, said spacers each having an arm for installation between said skeletal members and a stem extending from said arm, at least some of said spacers having a stem and an arm extending from said stem, said arm having a bump on one side thereof and an engagement surface on the other side thereof, said spacing dimension being the distance between the engagement surface and the region of said bump of maximum distance from said engagement surface, said bump having a height different for each of said spacers whereby a selected spacer may be used to establish a corresponding spacing dimension.

36. Spacing kit as claimed in claim 35, wherein the arm of at least one of said spacers is a substantially flat blade having opposite substantially flat surfaces, said spacing dimension being the thickness of said blade between said substantially flat surfaces.

37. Spacing kit as claimed in claim 36, wherein each bump is defined by a curved outer edge to permit limited rotation of said spacer about said curved outer edge in response to movement of the stem.

38. Spacing kit as claimed in claim 36, wherein each bump includes transversely spaced keels to resist transverse movement of the spacer when the latter is installed between skeletal members.

39. Spacing kit as claimed in claim 36, wherein each bump cooperates with its arm and stem to define a recess therebetween.

40. Spacing kit as claimed in claim 35, wherein each bump is defined by a curved outer edge to permit limited rotation of said spacer about said curved outer edge in response to movement of the stem

41. Spacing kit as claimed in claim 36, wherein each bump cooperates with its arm and stem to define a recess therebetween.