Meniscus Prosthetic Devices with Anti-Migration Features

• US 20090259312A1
• Filed: 04/09/2008
• Published: 10/15/2009
• Est. Priority Date: 04/09/2008
• Status: Active Grant

• Current Assignee: Active Implants Corporation
• Original Assignee: Active Implants Corporation
• Inventors: Shterling, Avraham, Linder-Ganz, Eran, Weissberg, Noam, Zur, Gal
• Granted Patent: US 8,361,147 B2
• Time in Patent Office: Days
• US Class Current: 623/14.120
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3804 for elbows
• CPC Class Codes: A61F 2/3872 Meniscus for implantation between the natural bone surfaces
• CPC Class Codes: A61F 2/40 for shoulders
• CPC Class Codes: A61F 2/4241 for hands, e.g. fingers
• CPC Class Codes: A61F 2/468 Testing instruments for artificial joints for testing non-implantable prostheses A61F2/76
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30069 elastomeric
• CPC Class Codes: A61F 2002/30074 stretchable
• CPC Class Codes: A61F 2002/30116 partial circles, i.e. circular segments
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30566 Helical springs
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30673 Lubricating means, e.g. synovial pocket
• CPC Class Codes: A61F 2002/3071 Identification means; Administration of patients
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30906 : shot- sand- or grit-blasted
• CPC Class Codes: A61F 2002/3093 : for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/30937 : with cut-outs
• CPC Class Codes: A61F 2002/30948 : using computerized tomography, i.e. CT scans
• CPC Class Codes: A61F 2002/30952 : using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30955 : using finite-element analysis
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/3096 : trimmed or cut to a customised size
• CPC Class Codes: A61F 2002/30962 : using stereolithography
• CPC Class Codes: A61F 2002/3895 : unicompartimental
• CPC Class Codes: A61F 2002/4633 : for selection of endoprosthetic joints or for pre-operative planning
• CPC Class Codes: A61F 2210/0057 : stretchable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0089 : coded with symbols, e.g. dots, numbers, letters, words

Abstract

A prosthetic device for use as an artificial meniscus is disclosed. The prosthetic device restores shock absorption, stability, and function to the knee joint after removal of the damaged natural meniscus. In some embodiments, the prosthetic device includes an anti-migration feature. The anti-migration feature is a bridge for engagement with a femur notch in some instances. Generally, the anti-migration feature allows the artificial meniscus to be implanted into the patient'"'"'s knee and maintain its position within the knee without penetrating the adjacent bone. The bridge is reinforced with fibers in some instances.

Claims

1. A prosthetic device for replacing a damaged meniscus of a knee joint, the prosthetic device comprising:

a central portion having an upper surface for engagement with a portion of a femur and an opposing lower surface for engagement with a portion of a tibia, the central portion formed of a resilient polyurethane;

an outer portion surrounding the central portion and having an increased thickness relative to the central portion, the outer portion comprising a first section having a generally semi-ellipsoidal profile similar to that of a natural meniscus and a second section extending between first and second ends of the first section, the second section sized and shaped to engage a femur notch to secure the meniscus prosthetic device within the knee joint without penetrating bone, the outer portion formed of the resilient polyurethane embedded with reinforcing fibers such that the outer portion has an increased radial stiffness relative to the central portion.

2. The prosthetic device of claim 1, wherein the second section has a height between about 4 mm and about 15 mm.

3. The prosthetic device of claim 2, wherein the second section has a width between about 1 mm and about 5 mm between an outer surface defining a perimeter of the prosthetic device and an inner surface that tapers into the upper surface of the central portion.

4. The prosthetic device of claim 3, wherein the second section comprises a first region adjacent the first end of the first section, a second region adjacent the second end of the first section, and a third region positioned between the first and second regions spaced from the first and second ends of the first section, wherein dimensions of the inner surface vary between the first, second, and third regions.

5. The prosthetic device of claim 4, wherein the inner surface has a first coronal radius of curvature between about 5 mm and about 70 mm in the first region, a second coronal radius of curvature between about 5 mm and about 50 mm in the second region, and a third coronal radius of curvature between about 10 mm and about 30 mm in the third region.

6. The prosthetic device of claim 4, wherein the inner surface has a first sagittal radius of curvature between about 10 mm and about 100 mm in the first region and a second sagittal radius of curvature between about 5 mm and about 70 mm in the second region.

7. The prosthetic device of claim 3, wherein the prosthetic device has a maximum length between about 20 mm and about 60 mm.

8. The prosthetic device of claim 7, wherein the prosthetic device has a maximum width between about 20 mm and about 65 mm.

9. The prosthetic device of claim 1, wherein the resilient polyurethane comprises a polycarbonate polyurethane.

10. The prosthetic device of claim 9, wherein the embedded fibers comprises an ultra high molecular weight polyethylene.

11. A meniscus prosthetic device, comprising:

a central portion having an upper surface for engagement with a portion of a femur and an opposing lower surface for engagement with a portion of a tibia;

an outer portion surrounding the central portion and having an increased thickness relative to the central portion, the outer portion comprising a first section having a generally semi-ellipsoidal profile similar to that of a natural meniscus and a second section extending between first and second ends of the first section, the second section sized and shaped to engage a femur notch to secure the meniscus prosthetic device within a knee joint without penetrating bone, the second section having an upper-inner surface tapering into the upper surface of the central portion, the upper-inner surface defined by a varying radius of curvature along a length of the second section.

12. The prosthetic device of claim 11, wherein the upper-inner surface comprises a first area adjacent the first end of the first section, the first area having a first radius of curvature between about 5 mm and about 70 mm in a direction substantially perpendicular to the length of the second section.

13. The prosthetic device of claim 12, wherein the upper-inner surface comprises a second area adjacent the second end of the first section, the second area having a second radius of curvature between about 5 mm and about 50 mm in a direction substantially perpendicular to the length of the second section.

14. The prosthetic device of claim 13, wherein the upper-inner surface comprises a third area between the first and second areas, the third area having a third radius of curvature between about 10 mm and about 30 mm in a direction substantially perpendicular to the length of the second section.

15. The prosthetic device of claim 14, wherein the first radius of curvature is about 12 mm, the second radius of curvature is about 11 mm, and the third radius of curvature is about 14 mm.

16. The prosthetic device of claim 13, wherein the first area has a fourth radius of curvature between about 10 mm and about 100 mm in a direction substantially parallel to the length of the second section, and wherein the second area has a fifth radius of curvature between about 5 mm and about 70 mm in a direction substantially parallel to the length of the second section.

17. The prosthetic device of claim 16, wherein the fourth radius of curvature is about 72 mm and the fifth radius of curvature is about 16 mm.

18. The prosthetic device of claim 11, wherein the outer portion has a thickness between about 1 mm and about 5 mm between the upper-inner surface and an outer surface opposite the upper-inner surface.

19. The prosthetic device of claim 18, wherein the thickness of the outer portion is about 2 mm.

20. A meniscus implant for secured positioning within a knee joint without requiring the penetration of bone, the implant comprising:

a central portion having an upper surface for intermittent engagement with a portion of a femur and an opposing lower surface for intermittent engagement with a portion of a tibia; and

an outer portion surrounding the central portion for continuous engagement with the femur and the tibia, the outer portion having an increased thickness relative to the central portion, the outer portion comprising a first section having a generally semi-ellipsoidal profile similar to that of a natural meniscus and a second section extending between first and second ends of the first section,

the second section having a first region adjacent the first end of the first section, a second region adjacent the second end of the first section, and third region between the first and second regions,

the first region of the second section having a height between about 4 mm and about 15 mm, a first radius of curvature along the length of the second section between about 5 mm and about 70 mm, and a second radius of curvature perpendicular to the length of the second section between about 10 mm and about 100 mm;

the second region of the second section having a height between about 4 mm and about 15 mm, a third radius of curvature along the length of the second section between about 5 mm and about 50 mm, and a fourth radius of curvature perpendicular to the length of the second section between about 5 mm and about 70 mm;

the third region of the second section having a height between about 4 mm and about 15 mm and a first radius of curvature along the length of the second section between about 10 mm and about 30 mm.