Meniscus Prosthetic Device

• US 20080086210A1
• Filed: 10/05/2007
• Published: 04/10/2008
• Est. Priority Date: 10/09/2006
• Status: Active Grant

• Current Assignee: Active Implants Corporation
• Original Assignee: Active Implants Corporation
• Inventors: Fox, Howard
• Granted Patent: US 8,192,491 B2
• Time in Patent Office: Days
• US Class Current: 623/14.12
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/3872 Meniscus for implantation between the natural bone surfaces
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A prosthetic device that may be utilized as an artificial meniscus is disclosed. The prosthetic device can restore shock absorption, stability, and function to the knee after the damaged natural meniscus is removed and replaced with the prosthetic device. In some embodiments, the meniscus includes an integral fixation anchor and additional features that minimize the requirement for modification of the implant for proper fit during surgery.

Claims

1. A prosthetic device for placement between a tibial plateau and a femoral condyle, the prosthetic device comprising:

a body portion comprising a semi-ellipsoidal outer portion and a central body portion, the outer portion having an increased thickness relative to the central body portion, wherein the semi-ellipsoidal outer portion surrounds a majority of the central body portion and wherein the central body portion has an upper surface configured for articulating engagement with the femoral condyle and a lower surface configured for engagement with the tibial plateau, the upper surface being at least partially concave and the lower surface being at least partially convex;

a fixation member extending from and substantially perpendicular to the bottom surface of the body portion, the fixation member configured to engage with a prepared opening in the tibial plateau to fixedly engage the prosthetic device to the tibia;

wherein the body portion and the fixation member comprise a monolithic structure formed of a resiliently flexible polymeric material.

2. The prosthetic device of claim 1, wherein the resiliently flexible polymeric material is a medical grade polyurethane based material.

3. The prosthetic device of claim 1, wherein a section of the central body portion defines an outer boundary of the prosthetic device.

4. The prosthetic device of claim 3, wherein the section of the central body portion has substantially the same thickness as the majority of the central body portion.

5. The prosthetic device of claim 3, wherein the section of the central body portion has an increased thickness relative to the majority of the central body portion.

6. The prosthetic device of claim 3, wherein the outer boundary extends between a first end of the semi-ellipsoidal outer portion and a second end of the semi-ellipsoidal outer portion.

7. The prosthetic device of claim 6, wherein the outer boundary comprises a substantially planar surface and wherein the fixation member extends substantially parallel to the outer boundary.

8. The prosthetic device of claim 1, further comprising a fixation device for further securing the prosthetic device to the tibial plateau.

9. The prosthetic device of claim 8, wherein the fixation device includes an opening extending therethrough for receiving a bone screw.

10. The prosthetic device of claim 1, wherein the fixation member has a keyhole shaped cross section.

11. The prosthetic device of claim 1, wherein the fixation member comprises a dove-tail.

12. The prosthetic device of claim 1, wherein the upper surface includes at least one recess therein.

13. The prosthetic device of claim 12, wherein the at least one recess is positioned at a contact point between the femur and the upper surface, and wherein the at least one recess is configured for receiving synovial fluid.

14. The prosthetic device of claim 1, wherein the semi-ellipsoidal outer portion comprises a deformation control element.

15. The prosthetic device of claim 14, wherein the deformation control element comprises a filament extending within a portion of the semi-ellipsoidal outer portion.

16. The prosthetic device of claim 15, wherein the filament is positioned within a recess in the semi-ellipsoidal outer portion.

17. The prosthetic device of claim 14, wherein the deformation control element comprises a material having increased stiffness relative to the central body portion.

18. A prosthetic device for replacing a natural meniscus, the prosthetic device comprising:

a central body portion comprising a flexible polymeric material, the central body portion having an upper articulating bearing surface for movingly engaging a femoral condyle and a lower articulating bearing surface for movingly engaging a tibial plateau;

an outer body portion completely surrounding the central body portion and having an increased thickness with respect to the central body portion, the outer body portion configured to limit movement of the femoral condyle with respect to the upper articulating bearing surface of the central body portion, the outer body portion having an increased stiffness with respect to the central body portion;

wherein the central body portion and the outer body portion comprise a monolithic structure; and

wherein the prosthetic device is configured for implantion without removing any portion of the tibial plateau.

19. The prosthetic device of claim 18, wherein a majority of the outer body portion has a first thickness and a minority of the outer body portion has a second thickness, the first thickness being greater than the second thickness.

20. The prosthetic device of claim 19, wherein the second thickness is approximately half of the first thickness.

21. The prosthetic device of claim 18, wherein the upper surface comprises a concave surface and the lower surface comprises a convex surface.

22. The prosthetic device of claim 18, wherein the outer body portion comprises a filament extending therethrough, the filament increasing overall the stiffness of the outer body portion.

23. A meniscus implant comprising:

a body portion comprising a semi-ellipsoidal outer portion and a central body portion, the outer portion having an increased thickness relative to the central body portion, the semi-ellipsoidal outer portion surrounding a majority of the central body portion,

wherein a filament is positioned within a portion of the semi-ellipsoidal outer portion such that the outer portion has an increased stiffness relative to the central body portion,

wherein the central body portion has an upper surface configured for articulating engagement with the femoral condyle and a lower surface configured for engagement with the tibial plateau, the upper surface being at least partially concave and having at least one recess, the lower surface being at least partially convex, a section of the central body portion defining a substantially planar outer boundary of the prosthetic device;

a fixation member extending from and substantially perpendicular to the bottom surface of the body portion, the fixation member configured to engage with a prepared opening in the tibial plateau to fixedly engage the prosthetic device to the tibia, the fixation member having a key-hole shaped cross-section and the fixation member extending substantially parallel to the outer boundary defined by the central body portion;

a fixation tab extending from the semi-ellipsoidal outer portion, the fixation tab having an opening therein for receiving a bone fixation member;

wherein the body portion, the fixation member, and the fixation tab comprise a monolithic structure formed of a polymeric material.