STABILIZED KNEE PROSTHESIS

• US 20160374814A1
• Filed: 09/08/2016
• Published: 12/29/2016
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: Collazo, Carlos E., Servidio, Damon J.
• Granted Patent: US 10,376,371 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3836 Special connection between upper and lower leg, e.g. constrained
• CPC Class Codes: A61F 2/3854 with ball and socket joint
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/3886 for stabilising knees against anterior or lateral dislocations
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30362 with possibility of relative movement between the protrusion and the recess
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit

Abstract

A knee prosthesis includes a femoral component, a tibial component, and a coupling component interconnecting the femoral component and the tibial component. The tibial component includes ball. The femoral component is configured to move relative to the tibial component. The coupling component defines an internal cavity including a first spherical end portion and a second spherical end portion. The internal cavity is dimensioned to receive the ball of the tibial component. The ball is repositioned between the first spherical end portion and the second spherical end portion of the internal cavity upon movement of the femoral component relative to the tibial component.

Claims

1. A method of varying an angular constraint of a knee prosthesis comprising:

inserting a portion of a stabilizing post coupled to a tibial baseplate within a housing of a femoral component, the stabilizing post having a thickness and movably interconnecting the femoral component to the tibial baseplate; and

allowing the femoral component to articulate with respect to the tibial baseplate,

wherein the stabilizing post causes the knee prosthesis to have an angular constraint and increasing the thickness of the stabilizing post increases the angular constraint of the knee prosthesis.

2. The method of claim 1, wherein a tibial insert is coupled to the tibial baseplate and the femoral component contacts and articulates with respect to the tibial insert.

3. The method of claim 1, wherein the stabilizing post has an outer surface with a protrusion extending outwards from the outer surface, the protrusion being configured to engage the wall of the housing during hyperextension of a knee.

4. The method of claim 3, wherein the stabilizing post includes a first post and a second post at least partially positioned within the first post, the first post having the outer surface with the protrusion extending outwards therefrom.

5. The method of claim 4, wherein the housing of the femoral component includes an enclosed internal cavity adapted to receive a portion of the first post.

6. The method of claim 4, wherein the first post includes a rounded end positioned within the housing of the femoral component.

7. The method of claim 4, wherein the second post includes a first elongated member positioned inside the first post and a second elongated member positioned within the tibial component.

8. The method of claim 4, wherein the first post has an inner bore configured to receive the second post.

9. The method of claim 4, wherein the tibial component includes a cavity and a portion of the stabilizing post is positioned within the cavity to secure the second post relative to the tibial component.

10. The method of claim 1, wherein the wall is an anterior wall of the housing.

11. A method of determining a preferred angular constraint of a knee prosthesis comprising:

inserting a portion of a first stabilizing post having a first thickness coupled to a tibial baseplate within a housing of a femoral component, the first stabilizing post movably interconnecting the femoral component to the tibial baseplate;

allowing the femoral component to articulate with respect to the tibial baseplate to determine a first angular constraint of the knee prosthesis;

inserting a portion of a second stabilizing post having a second thickness coupled to a tibial baseplate within the housing of the femoral component, the second stabilizing post movably interconnecting the femoral component to the tibial baseplate; and

allowing the femoral component to articulate with respect to the tibial baseplate to determine a second angular constraint of the knee prosthesis, the second angular constraint being greater than the first angular constraint

wherein the preferred angular constraint is chosen from the first and second determined angular constraints.

12. The method of claim 11, wherein a tibial insert is coupled to the tibial baseplate and the femoral component contacts and articulates with respect to the tibial insert.

13. The method of claim 11, wherein each of the first and second stabilizing posts have an outer surface with a protrusion extending outwards from the outer surface, the protrusion being configured to engage the wall of the housing during hyperextension of a knee.

14. The method of claim 13, wherein each of the first and second stabilizing posts include a first post and a second post at least partially positioned within the first post, the first post having the outer surface with the protrusion extending outwards therefrom.

15. The method of claim 14, wherein the housing of the femoral component includes an enclosed internal cavity adapted to receive a portion of each of the first posts.

16. The method of claim 14, wherein each of the first posts include a rounded end positioned within the housing of the femoral component.

17. The method of claim 14, wherein each of the first posts have an inner bore configured to receive the second post.

18. The method of claim 11, wherein the wall is an anterior wall of the housing.

19. A kit for determining a preferred angular constraint of a knee prosthesis comprising:

a tibial baseplate;

a femoral component having a housing including an enclosed internal cavity adapted to receive a portion of a stabilizing post;

a first stabilizing post having a first thickness, the first stabilizing post coupled at a first end to the tibial baseplate and received at a second end within the housing of a femoral component, the first stabilizing post configured to movably interconnect the femoral component to the tibial baseplate such that the knee prosthesis has a first angular constraint;

a second stabilizing post having a second thickness, the second stabilizing post coupled at a first end to the tibial baseplate and received at a second end within the housing of a femoral component, the second stabilizing post configured to movably interconnect the femoral component to the tibial baseplate such that the knee prosthesis has a second angular constraint greater than the first angular constraint.