Unicondylar tibial knee implant

• US 9,445,909 B2
• Filed: 03/14/2014
• Issued: 09/20/2016
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Original Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Inventors: Cohen, Robert Craig, Frank, Philip Harris
• Primary Examiner(s): Stewart, Alvin
• Application Number:
  US14/210,921
• Publication Number:
  US 20140343681A1
• Time in Patent Office: 921 Days
• Field of Search: 623/20.3, 623/20.32, 623 1911- 1914, 623 2014- 2017, 623 2111- 2119, 623 235- 2355, 623 2372- 2376
• US Class Current: 1/1
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30967 Diffusion bonding
• CPC Class Codes: A61F 2002/3895 unicompartimental

Abstract

An implant providing for both short and long term stability and fixation is disclosed. The implant includes a plurality of projections extending from a bone contacting surface, and a porous material covering at least portions of the surface and projections. The orientation of the projections and the porous material provide for the stability and fixation. Methods of forming and utilizing the implant are also disclosed.

Claims

1. An orthopedic implant for replacing a portion of a bone comprising:

a bone contacting surface;

a hole configured to accept a bone screw at a plurality of different angles; and

a keel extending from the bone contacting surface, the keel including a first projection with a first longitudinal axis and a second projection with a second longitudinal axis, wherein the first and second longitudinal axes are oriented orthogonally to each other, and the first and second projections are separated from each other by the hole.

2. The orthopedic implant of claim 1, wherein the hole includes a plug removable upon the application of a force.

3. The orthopedic implant of claim 1, further comprising at least one fin associated with the first projection and extending oblique to the first longitudinal axis.

4. The orthopedic implant of claim 3, wherein the fin is shaped to engage the bone.

5. The orthopedic implant of claim 4, wherein the fin is configured to enter into an unprepared portion of the bone.

6. The orthopedic implant of claim 1, further comprising at least one extension associated with the second projection and extending oblique to the second longitudinal axis.

7. The orthopedic implant of claim 6, wherein the at least one extension is shaped to engage the bone.

8. The orthopedic implant of claim 7, wherein the at least one extension frictionally engages the bone.

9. The orthopedic implant of claim 1, further comprising a porous portion adapted to allow for the bone to grow therein.

10. The orthopedic implant of claim 9, wherein the porous portion covers at least a portion of the bone contacting surface and at least a portion of the keel.

11. The orthopedic implant of claim 10, further comprising a solid portion at a distal end of the keel.

12. The orthopedic implant of claim 9, wherein the porous portion defines a first porous surface and at least one boundary strut extending from the surface in a first direction.

13. The orthopedic implant of claim 12, wherein the boundary strut extends from 0 to 10 degrees from normal the first porous surface.

14. The orthopedic implant of claim 1, further comprising a third projection.

15. The orthopedic implant of claim 1, further comprising a bearing component attachable to the implant.

16. The orthopedic implant of claim 1, wherein the implant is a unicondylar tibial baseplate.

17. A kit comprising the implant of claim 1 and at least one other implant.

18. A tibial baseplate comprising:

a bone contacting surface having anterior, posterior, medial and lateral sides;

a first projection extending from the bone contacting surface and having a first length extending in a first direction between the anterior and posterior ends;

a second projection extending from the bone contacting surface and having a second length extending in a second direction between the medial and lateral sides, the second projection being separated from the first projection;

an aperture for receiving a bone screw; and

a porous material for promoting bone ingrowth, the porous material at least partially covering the bone contacting surface, the first projection and the second projection, wherein the porous material defines a plurality of boundary struts extending from 0 to 10 degrees from normal to the bone contacting surface.

19. The tibial baseplate of claim 18, further comprising a third projection.

20. The tibial baseplate of claim 18, wherein the first and second projections are separated from each other by the aperture.

21. The tibial baseplate of claim 18, wherein the aperture is configured to accept a bone screw at a plurality of different angles.

22. The tibial baseplate of claim 18, wherein the aperture includes a plug removable upon the application of a force.

23. The tibial baseplate of claim 18, further comprising at least one fin or extension associated with at least one of the first and second projections.

24. The tibial baseplate of claim 23, wherein the fin is configured to enter into an unprepared portion of the bone and the extension frictionally engages the bone.

25. The tibial baseplate of claim 18, further comprising a solid portion at distal ends of the first and second projections.

26. A tibial baseplate comprising:

a bone contacting surface having anterior, posterior, medial and lateral sides;

a first projection extending from the bone contacting surface and having a first length extending in a first direction between the anterior and posterior ends;

a second projection extending from the bone contacting surface and having a second length extending in a second direction between the medial and lateral sides, the second projection being separated from the first projection;

an aperture for receiving a bone screw;

a plug at least partially covering the aperture, the plug being removable upon the application of a force; and

a porous material for promoting bone ingrowth, the porous material at least partially covering the bone contacting surface, the first projection and the second projection, wherein the porous material defines a plurality of boundary struts extending from the bone contacting surface from 0 to 10 degrees from normal to the bone contacting surface.