METHODS AND TOOLS FOR FEMORAL RESECTION IN PRIMARY KNEE SURGERY

• US 20030018338A1
• Filed: 12/23/2000
• Published: 01/23/2003
• Est. Priority Date: 12/23/2000
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: McGovern, Michael J., Meyers, Reese K., Axelson, Stuart L. Jr.
• Granted Patent: US 6,558,391 B2
• Time in Patent Office: Days
• US Class Current: 606/89
• CPC Class Codes: A61B 17/155 Cutting femur

Abstract

Femoral resection tools of the present invention include a posterior condyle alignment guide, an IM rod with an adjustable valgus bushing assembly, left and right external rotation plates, an anterior sizing boom having a stylus and a pair of medial/lateral drill guide assemblies (in one embodiment of the invention the drill guide assemblies are the combination of medial/lateral extension arms and attached (detachable) proximal positioning fixtures; in another embodiment, the proximal positioning fixtures are not part of the drill guide assembly per se), a plurality of self-tapping screws, proximal positioning fixtures (apart from any positioning fixtures that may be integrated into a drill guide assembly), and different size cutting guide blocks, each adapted to fit over the proximal positioning fixtures. According to the methods of the invention, the valgus bushing is attached to the appropriate external rotation guide plate and both are attached to the posterior alignment guide. The IM rod is inserted through the valgus bushing and in the IM canal so that the assembly rests against the distal and posterior surfaces of the femur. The stylus of the sizing boom is moved over the anterior femur and a size is indicated by indicia on a vertical post of the sizing boom. The medial/lateral drill guides are moved against the medial and lateral sides of the femur and two fixation pins (self-tapping screws) are inserted through the holes in each drill guide. The drill guide assembly, sizing boom, and alignment assembly are all removed leaving only the proximal positioning fixtures and four fixation pins. Another pair of proximal positioning fixtures may be selected; and if so are slid onto the fixation pins. A cutting block is slid onto the proximal positioning fixtures. Fixation pins are used to secure the cutting block. With the cutting block in place, five resections can be performed.

Claims

1. A cutting guide for resecting the distal femur prior to implanting a prosthetic component, said guide comprising:

(a) a block having a plurality of guiding surfaces, said plurality of guiding surfaces including;

(a1) an anterior cutting guide surface for resecting the anterior cortex of the femur;

(a2) a posterior cutting guide surface for resecting the posterior condyles;

(a3) an anterior chamfer cutting guide surface;

(a4) a posterior chamfer cutting guide surface; and

(a5) a distal cutting guide surface for resecting the distal end of the femur; and

(b) means for securing said block to the distal femur.

2. A cutting guide according to claim 1 further comprising means for locating the proximal-distal location of the cutting guide relative to the distal end of the femur.

3. A cutting guide according to claim 1 wherein said anterior cutting guide surface includes a planar surface and two rods.

4. A cutting guide according to claim 3 wherein said posterior cutting guide surface includes a planar surface and two rods.

5. A cutting guide according to claim 4 wherein said posterior chamfer cutting guide surface includes two planar surfaces and a rod.

6. A cutting guide according to claim 5 wherein said anterior chamfer cutting guide surface includes two planar surfaces and a rod.

7. A cutting guide according to claim 6 wherein said distal cutting guide surface includes a planar surface and two rods.

8. A cutting guide according to claim 1 wherein said block defines a pair of pin receiving holes and said means for securing said block includes a pair of pins dimensioned to fit through said holes.

9. A cutting guide according to claim 1 further comprising means for locating the anterior-posterior location of the cutting guide relative to the distal end of the femur.

10. A set of tools for resecting the distal end of the distal femur prior to implanting a prosthetic component, said set of tools comprising:

(a) locating means for locating a medial location and a lateral location on the femur;

(b) a pair of positioning fixtures adapted to be affixed to said medial location and said lateral location;

(c) a cutting block having a plurality of guiding surfaces and means for engaging with said pair of positioning fixtures; and

(d) means for securing said block to the distal femur.

11. A set of tools according to claim 10, wherein said locating means includes an anterior sizing boom and an IM rod, said anterior sizing boom having a pair of drill guides adapted to overlie said medial location and said lateral location.

12. A set of tools according to claim 11, wherein said locating means includes a posterior alignment guide.

13. A set of tools according to claim 12, wherein said locating means includes a valgus bushing assembly and an external rotation fixture.

14. A set of tools according to claim 10, wherein said pair of positioning fixtures includes a set of pairs of positioning fixtures, each pair interacting with said cutting block to locate said cutting block a different proximal-distal distance from the distal end of the femur.

15. A set of tools according to claim 10, wherein said pair of positioning fixtures includes a set of pairs of positioning fixtures, each pair interacting with said cutting block to locate said cutting block a different anterior-posterior distance from the distal end of the femur.

16. A set of tools according to claim 14, wherein said pairs of positioning fixtures locate said cutting block a distance from the distal end of the femur to resect an amount selected from the group consisting of 8 mm, 10 mm, 12 mm and 14 mm.

17. A set of tools according to claim 15, wherein said pairs of positioning fixtures locate said cutting block +/−

2 mm anteriorally-posteriorally.

18. A set of tools according to claim 13, wherein said external rotation fixture includes a set of external rotation fixtures having rotation values selected from the group consisting of 0 degrees, 3 degrees left, 3 degrees right, 5 degrees left, and 5 degrees right.

19. A set of tools according to claim 10, wherein said plurality of guiding surfaces includes:

(a1) an anterior cutting guide surface for resecting the anterior cortex of the femur;

(a2) a posterior cutting guide surface for resecting the posterior condyles;

(a3) an anterior chamfer cutting guide surface;

(a4) a posterior chamfer cutting guide surface; and

(a5) a distal cutting guide surface for resecting the distal end of the femur.

20. A set of tools according to claim 19 wherein said anterior cutting guide surface includes a planar surface and two rods.

21. A set of tools according to claim 20 wherein said posterior cutting guide surface includes a planar surface and two rods.

22. A set of tools according to claim 21 wherein said posterior chamfer cutting guide surface includes two planar surfaces and a rod.

23. A set of tools according to claim 22 wherein said anterior chamfer cutting guide surface includes two planar surfaces and a rod.

24. A set of tools according to claim 23 wherein said distal cutting guide surface includes a planar surface and two rods.

25. A set of tools according to claim 24 wherein said block defines a pair of pin receiving holes and said means for securing said block includes a pair of pins dimensioned to fit through said holes.

27. A method according to claim 26 further comprising the step of locating the proximal-distal location of the cutting guide relative to the distal end of the femur.

28. A method according to claim 26 wherein the anterior cutting guide surface includes a planar surface and two rods and said step of resecting the anterior cortex includes placing a saw between the planar surface and the two rods.

29. A method according to claim 28 wherein posterior cutting guide surface includes a planar surface and two rods and said step of resecting the posterior condyles includes placing a saw between the planar surface and the two rods.

30. A method according to claim 29 wherein the posterior chamfer cutting guide surface includes two planar surfaces and a rod and said step of resecting the posterior chamfer includes placing a saw between the two planar surfaces and against the rod.

31. A method according to claim 30 wherein the anterior chamfer cutting guide surface includes two planar surfaces and a rod and said step of resecting the anterior chamfer includes placing a saw between the two planar surfaces and against the rod.

32. A method according to claim 31 wherein the distal cutting guide surface includes a planar surface and two rods and said step of resenting the distal surface of the femur includes placing a saw between the planar surface and the two rods.

33. A method according to claim 26 wherein the block defines a pair of pin receiving holes and said step of securing the block includes inserting a pair of pins dimensioned to fit through said holes into the femur.

34. A method according to claim 26 further comprising the step of locating the anterior-posterior location of the cutting guide relative to the distal end of the femur.

36. A method according to claim 35, wherein said step of locating includes attaching an anterior sizing boom and an IM rod to the femur and attaching a pair of drill guides adapted to overlie the medial location and the lateral location to the sizing boom.

37. A method according to claim 36, wherein said step of locating means includes coupling a posterior alignment guide to the IM rod.

38. A method according to claim 37, wherein said step of locating includes coupling a valgus bushing assembly and an external rotation fixture to the IM rod.

39. A method according to claim 35, wherein said step of affixing positioning fixtures includes choosing a pair of positioning fixtures from a group of pairs wherein each pair interacts with the cutting block to locate the cutting block a different proximal-distal distance from the distal end of the femur.

40. A method according to claim 35, wherein said step of affixing positioning fixtures includes choosing a pair of positioning fixtures from a group of pairs wherein each pair interacts with the cutting block to locate the cutting block a different anterior-posterior distance from the distal end of the femur.

41. A method according to claim 39, wherein the pairs of positioning fixtures locate the cutting block a distance from the distal end of the femur to resect an amount selected from the group consisting of 8 mm, 10 mm, 12 mm and 14 mm.

42. A method according to claim 15, wherein the pairs of positioning fixtures locate the cutting block +/−

2 mm anteriorally-posteriorally.

43. A method according to claim 38, wherein the external rotation fixture includes a set of external rotation fixtures having rotation values selected from the group consisting of 0 degrees, 3 degrees left, 3 degrees right, 5 degrees left, and 5 degrees right.

44. A method according to claim 35, wherein the plurality of guiding surfaces includes:

(a1) an anterior cutting guide surface for resecting the anterior cortex of the femur;

(a2) a posterior cutting guide surface for resecting the posterior condyles;

(a3) an anterior chamfer cutting guide surface;

(a4) a posterior chamfer cutting guide surface;

(a5) a distal cutting guide surface for resecting the distal end of the femur; and

said method further comprising the steps of;

(e) resecting the anterior cortex of the femur using a saw placed against the anterior cutting guide surface;

(f) resecting the posterior condyles using a saw placed against the posterior cutting guide surface;

(g) resecting an anterior chamfer using a saw placed against the anterior chamfer cutting guide surface;

(e) resecting a posterior chamfer using a saw placed against the posterior chamfer cutting guide surface; and

(h) resecting the distal end of the femur using a saw placed against the distal cutting guide surface.

45. A method according to claim 44 wherein the anterior cutting guide surface includes a planar surface and two rods and said step of resecting the anterior cortex includes placing a saw between the planar surface and the two rods.

46. A method according to claim 45 wherein the posterior cutting guide surface includes a planar surface and two rods and said step of resecting the posterior condyles includes placing a saw between the planar surface and the two rods.

47. A method according to claim 46 wherein the posterior chamfer cutting guide surface includes two planar surfaces and a rod and said step of resecting the posterior chamfer includes placing a saw between the two planar surfaces and against the rod.

48. A method according to claim 47 wherein the anterior chamfer cutting guide surface includes two planar surfaces and a rod and said step of resecting the anterior chamfer includes placing a saw between the two planar surfaces and against the rod.

49. A method according to claim 48 wherein the distal cutting guide surface includes a planar surface and two rods and said step of resecting the distal femur includes placing a saw between the planar surface and the two rods.

50. A method according to claim 49 wherein the block defines a pair of pin receiving holes and said step for securing said block includes inserting a pair of pins dimensioned to fit through said holes into the femur.

51. Apparatus according to claim 11 wherein said positioning fixtures are integrated with said drill guide.

52. Apparatus according to claim 11 wherein said positioning fixtures are modular.

53. Apparatus according to claim 11 wherein each of said positioning fixtures are detachably attached to a drill guide extension arm to form an integrated drill guide assembly.

54. A method according to claim 36 wherein said positioning fixtures are integrated with said drill guide.

55. A method according to claim 36 wherein said positioning fixtures are modular.

56. A method according to claim 36 wherein each of said positioning fixtures are detachably attached to a drill guide extension arm to form an integrated drill guide assembly.

26. A method for resecting the distal femur prior to implanting a prosthetic component, said method comprising the steps of:

(a) securing a cutting block to the distal end of the femur, the block having a plurality of guiding surfaces, the plurality of guiding surfaces including;

(a1) an anterior cutting guide surface for resecting the anterior cortex of the femur;

(a2) a posterior cutting guide surface for resecting the posterior condyles;

(a3) an anterior chamfer cutting guide surface;

(a4) a posterior chamfer cutting guide surface; and

(a5) a distal cutting guide surface for resecting the distal end of the femur;

(b) resecting the anterior cortex of the femur using a saw placed against the anterior cutting guide surface;

(c) resecting the posterior condyles using a saw placed against the posterior cutting guide surface;

(d) resecting an anterior chamfer using a saw placed against the anterior chamfer cutting guide surface;

(e) resecting a posterior chamfer using a saw placed against the posterior chamfer cutting guide surface; and

(f) resecting the distal end of the femur using a saw placed against the distal cutting guide surface.

35. A method for resecting the distal end of the distal femur prior to implanting a prosthetic component, said method comprising the steps of:

(a) locating a medial location and a lateral location on the femur;

(b) affixing positioning fixtures to the medial location and the lateral location;

(c) placing a cutting block having a plurality of guiding surfaces on the pair of positioning fixtures, and

(d) securing the block to the distal femur.