Methods and tools for femoral resection in primary knee surgery

• US 6,558,391 B2
• Filed: 12/23/2000
• Issued: 05/06/2003
• Est. Priority Date: 12/23/2000
• Status: Expired due to Fees

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Stryker Technologies Corporation (Stryker Corporation)
• Inventors: Meyers, Reese K., Axelson, Stuart L. Jr., McGovern, Michael J.
• Primary Examiner(s): Smith, Jeffrey A.
• Application Number:
  US09/746,800
• Publication Number:
  US 20030018338A1
• Time in Patent Office: 864 Days
• Field of Search: 606/86, 606/87, 606/88, 606/89, 606/96
• US Class Current: 606/88
• 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. Methods for utilizing the aforementioned tools so that five resections can be performed are also described.

Claims

1. An instrument for resecting the distal femur, comprising:

a plurality of cutting guide blocks;

a pair of neutral positioning fixtures, for positioning any one of said cutting guide blocks on the distal femur;

a plurality of offset positioning fixtures for positioning any one of said cutting guide block at an offset position;

an alignment assembly for positioning said pair of positioning fixtures, said alignment assembly including an IM rod, a valgus bushing, a posterior alignment guide for locating an anterior-posterior location of said positioning fixtures, and a plurality of external rotation guides for providing an external rotation; and

a drill guide cooperating with said alignment assembly for drilling holes in the distal femur for attaching said pair of positioning fixtures to the distal femur.

2. An instrument according to claim 1, wherein said plurality of external rotation guides includes an external rotation guide providing 3 degrees left external rotation, an external rotation guide providing 3 degrees right external rotation, an external rotation guide providing 5 degrees left external rotation, an external rotation guide providing 5 degrees right external rotation and an external rotation guide providing zero degrees rotation.

3. An instrument according to claim 2, wherein said posterior alignment guide includes:

a vertical portion for abutting the distal end of the femur; and

a pair of feet for abutting the posterior condyles of the distal femur,

wherein said alignment assembly is assembled by selecting an appropriate external rotation guide from said plurality of external rotation guides, attaching said appropriate external rotation guide to said valgus bushing, inserting said IM rod through said valgus bushing, said appropriate external rotation guide and said posterior alignment guide and inserting said IM rod into the IM canal of the femur until said alignment assembly abuts the distal end of the femur.

4. An instrument according to claim 1, comprising a sizing boom cooperable with said external rotation guide and said posterior alignment guide for selecting said one cutting guide block from said plurality of cutting guides.

5. An instrument according to claim 4, wherein said sizing boom includes posts for attaching to said external rotation guide and a vertically adjustable stylus for contacting the most prominent aspect of the anterior lateral cortex to determine the appropriate size for said one cutting guide.

6. An instrument according to claim 5, wherein said pair of positioning fixtures are removably attached to one end of said drill guide and another end of said drill guide is removably attached to said sizing boom.

7. An instrument according to claim 6 further comprising self tapping pins for attaching said pair of positioning fixtures to the distal femur.

8. An instrument according to claim 1, wherein each of said plurality of external rotation guides comprises a pair of tabs for visually peferencing the position of said external rotation guide with respect to the posterior condyles.

9. An instrument for positioning a cutting guide on the distal femur, comprising:

an alignment assembly including;

an IM rod for inserting into the IM canal;

a valgus bushing attached to said IM rod;

an external rotation guide for providing an external rotation, said external rotation guide attached to said valgus bushing; and

a posterior alignment guide attached to said external rotation guide and abutting the posterior condyles of the distal femur;

a drill guide cooperable with said alignment assembly;

a pair of neutral positioning fixtures for receiving the cutting block on the distal femur at a neutral position, said neutral positioning fixtures being removably attached to said drill guide and attachable to the medial and lateral sides of the femur, wherein when said alignment assembly is assembled on the distal femur and said drill guide cooperates with said alignment assembly so as to position said neutral positioning fixtures on the medial and lateral sides of the femur; and

a plurality of pairs of offset positioning fixtures for receiving the cutting block of the distal femur at an offset orientation, each of said plurality pairs of offset positioning fixtures being attachable to the medial and lateral sides of the femur.

10. An instrument according to claim 9, comprising self tapping pins for attaching said pair of neutral positioning fixtures to the medial and lateral sides of the femur.

11. An instrument according to claim 10, wherein each of said plurality pairs of offset positioning fixtures may be attached to the medial and lateral sides of the femur via said self tapping pins.

12. An instrument according to claim 10, wherein said plurality of offset positioning fixtures includes at least one proximal-distal offset positioning fixture for receiving the cutting block at an orientation offset proximally/distally from the neutral position.

13. An instrument according to claim 12, wherein said at least one proximal-distal offset positioning fixture includes an offset positioning fixture for receiving the cutting block 2 mm offset from the neutral position, an offset positioning fixture for receiving the cutting block 4 mm offset from the neutral position, and an offset positioning fixture for receiving the cutting block 6 mm offset from the neutral position.

14. An instrument according to claim 10, wherein said plurality of offset positioning fixtures includes at least one anterior-posterior offset positioning fixture for receiving the cutting block at an orientation offset anteriorally/posteriorally from the neutral position.

15. An instrument according to claim 14, wherein said at least one anterior-posterior offset positioning fixture includes an anterior-posterior offset positioning fixture for receiving the cutting block at an orientation offset anteriorally/posteriorally from the neutral to a value selected from the range of about −

2 mm to about +2 mm.

16. An instrument for resecting the distal femur, comprising:

a plurality of cutting guide blocks, each of said plurality of cutting guide blocks having anterior cutting guide surface defining three points, a posterior cutting guide surface defining three points, an anterior chamfer guide surface defining three points, a posterior chamfer guide surface defining three points and a distal cutting guide surface defining three points;

a pair of positioning fixtures, for positioning one of said cutting guide blocks on the distal femur;

an alignment assembly for positioning said pair of positioning fixtures; and

a drill guide cooperating with said alignment assembly for drilling holes in the distal femur for attaching said pair of positioning fixtures to the distal femur;

a sizing boom attachable to said alignment assembly for selecting said one cutting guide block from said plurality of cutting guides, said sizing boom including an adjustable stylus for contacting the most prominent aspect of the anterior lateral cortex to determine the appropriate size for said one cutting guide.

17. An instrument according to claim 16, wherein each of said three points includes at least one rod.

18. An instrument according to claim 17, wherein each of said three points includes at least one planar surface.

19. An instrument according to claim 16, wherein each of said three points includes at least one planar surface.

20. An instrument according to claim 19, wherein each of said three points includes at least one rod.

21. An instrument according to claim 16, wherein said alignment assembly comprises an IM rod, a valgus bushing, a posterior alignment guide for locating an anterior-posterior location of said positioning fixtures, and a plurality of external rotation guides for providing an external rotation.

22. A method for resecting the distal femur, comprising the steps of:

locating an appropriate position for a cutting guide block on the distal femur;

determining an appropriate size cutting guide block;

removably attaching positioning fixtures to the distal femur at the appropriate position;

removably attaching the appropriate size cutting guide block to the positioning fixtures;

resecting the femur using a saw and the appropriate cutting guide block;

removing the appropriate size cutting guide block;

removably reattaching the appropriate size cutting guide block at an offset orientation; and

further resecting the femur.

23. A method according to claim 22, wherein the step of locating further includes:

selecting an appropriate external rotation guide from a plurality of external rotation guides;

attaching the appropriate external rotation guide to a valgus bushing;

forming an alignment assembly by inserting an IM rod through the valgus bushing, external rotation guide and a posterior alignment guide;

inserting the IM rod into the IM canal until the alignment assembly abuts the distal femur; and

attaching a drill guide including the positioning fixtures to the alignment assembly, wherein the positioning fixtures are located at the appropriate position.

24. A method according to claim 23, wherein said step of determining further includes:

attaching a sizing boom including a stylus and sizing indicia to the alignment assembly;

rotating the stylus until it contacts the anterior femur; and

reading the sizing indicia to determine the appropriate size for the cutting block.

25. A method according to claim 23, wherein the plurality of external rotation guides includes an external rotation guide providing 3 degrees left external rotation, an external rotation guide providing 3 degrees right external rotation, an external rotation guide providing 5 degrees left external rotation, an external rotation guide providing 5 degrees right external rotation and an external rotation guide providing zero degrees rotation.

26. A method according to claim 25, wherein said step of selecting further includes selecting offset positioning fixtures to offset the orientation of the cutting block proximally/distally.

27. A method according to claim 26, wherein the plurality of offset positioning fixtures includes an offset positioning fixture for offsetting the cutting block 2 mm proximally, an offset positioning fixture for offsetting the cutting block 4 mm proximally, and an offset positioning fixture for offsetting the cutting block 6 mm proximally.

28. A method according to claim 25, wherein said step of selecting further includes selecting offset positioning fixtures to offset the orientation of the cutting block anteriorally/posteriorally.

29. A method according to claim 28, wherein the plurality of offset positioning fixture includes an offset positioning fixture for offsetting the cutting block anteriorally/posteriorally to a value selected from the range of about −

2 mm to about +2 mm.

30. A method according to claim 22, wherein said step of removably reattaching the cutting guide block further includes the steps of:

determining the offset orientation;

selecting offset positioning fixtures from a plurality of offset positioning fixtures;

removably attaching offset positioning fixtures to the femur; and

the step of removably reattaching the cutting guide block further includes removably attaching the cutting guide block to the offset positioning fixtures to position the cutting guide at the offset orientation.

31. A method according to claim 22, further comprising the step of selecting the appropriate cutting guide blocks from a plurality of cutting guide blocks, each of said plurality of cutting guide blocks having anterior cutting guide surface defining three points, a posterior cutting guide surface defining three points, an anterior chamfer guide surface defining three points, a posterior chamfer guide surface defining three points and a distal cutting guide surface defining three points.

32. A method according to claim 31, wherein said step of resecting further includes the steps of:

resecting the anterior cortex of the femur using a saw placed between the three points of the anterior cutting guide surface;

resecting the posterior condyles of the femur using a saw placed between the three points of the posterior cutting guide surface;

resecting the anterior chamfer of the femur using a saw placed between the three points the anterior chamfer cutting guide surface;

resecting the posterior chamfer of the femur using a saw placed between the three points of the posterior chamfer cutting guide surface; and

resecting the distal end of the femur using a saw placed between the three points of the distal cutting guide surface.