Composite acetabular component

• US 6,966,932 B1
• Filed: 02/05/2002
• Issued: 11/22/2005
• Est. Priority Date: 02/05/2002
• Status: Active Grant

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Schroeder, David Wayne
• Primary Examiner(s): Shaver, Kevin
• Assistant Examiner(s): RAMANA, ANURADHA
• Application Number:
  US10/068,135
• Time in Patent Office: 1,386 Days
• Field of Search: 623/22.15, 623/22.17, 623/22.19, 623/22.2, 623/22.21, 623/22.24, 623/22.28, 623/22.29, 623/22.56
• US Class Current: 623/22.19
• 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 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30973 Two joined adjacent layers having complementary interlocking protrusions and recesses
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2210/0071 thermoplastic
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures
• CPC Class Codes: B29C 33/20 Opening, closing or clamping
• CPC Class Codes: B29C 37/0082 Mechanical anchoring B29C66/303 takes precedence
• CPC Class Codes: B29C 43/18 incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles B29C43/206 takes precedence
• CPC Class Codes: B29K 2023/0683 UHMWPE, i.e. ultra high molecular weight polyethylene
• CPC Class Codes: B29L 2031/7532 Artificial members, protheses

Abstract

Composite acetabular components, and methods of making and using same, are described. The composites consist of a ceramic liner having a backing of plastic material, such as but not limited to ultra high molecular weight polyethylene (UHMWPE), molded around the ceramic liner. The back surface of the ceramic liner is textured to enhance the mechanical bonding strength of the plastic backing to the textured ceramic liner during the molding process.

Claims

1. An acetabular liner component, comprising:

a ceramic insert portion having an inner surface and an outer surface; and

a biocompatible thermoplastic backing portion molded onto the outer surface of the ceramic insert portion when the biocompatible thermoplastic backing portion is in a substantially softened state;

a groove formed in an outer surface of said biocompatible thermoplastic backing portion adapted to receive an inter-connection member;

wherein the outer surface of the ceramic insert portion is provided with a micro-roughness having an arithmetical mean roughness in a range of about 5 to about 10 microns and a plurality of longitudinally disposed macro-grooves so as to increase the mechanical bonding between the biocompatible thermoplastic backing portion and the outer surface of the ceramic insert portion.

2. The composite acetabular liner component according to claim 1, wherein the ceramic insert portion has a substantially hemispherical shape.

3. The composite acetabular liner component according to claim 1, wherein the outer surface of the ceramic insert portion comprises a roughened surface.

4. The composite acetabular liner component according to claim 3, wherein the roughened surface has a ten-point mean roughness in a range of about 50 to about 75 microns.

5. The composite acetabular liner component according to claim 1, wherein the biocompatible thermoplastic backing portion has a substantially hemispherical surface, and wherein the macro-grooves are longitudinally oriented with respect to the hemispherical shape.

6. The composite acetabular liner component according to claim 1, wherein the biocompatible thermoplastic backing portion is comprised of polyethylene.

7. The composite acetabular liner component according to claim 1, wherein the biocompatible thermoplastic backing portion is comprised of ultra high molecular weight polyethylene.

8. A composite acetabular liner component, comprising:

a ceramic insert member, the ceramic insert member having a substantially hemispherical shape, the ceramic insert member having an inner surface and an outer surface; and

a biocompatible thermoplastic backing member molded onto the outer surface of the ceramic insert member when the biocompatible thermoplastic backing member is in a substantially softened state, the biocompatible thermoplastic backing member having a substantially hemispherical shape, the biocompatible thermoplastic backing member having an inner surface and an outer surface;

a connection system including a groove formed in the outer surface of said biocompatible thermoplastic backing member adapted to receive a locking member;

wherein the outer surface of the ceramic insert is provided with a roughened texture and a plurality of longitudinal macro-grooves so as to increase the mechanical bonding between the inner surface of the biocompatible thermoplastic backing member and the roughened texture of the outer surface of the ceramic liner member.

9. The composite acetabular liner component according to claim 8, wherein the texture comprises a micro-roughened surface.

10. The composite acetabular liner component according to claim 9, wherein the roughened surface has an arithmetical mean roughness in a range of about 5 to about 10 microns.

11. The composite acetabular liner component according to claim 8, wherein the biocompatible thermoplastic backing member is comprised of polyethylene which substantially penetrates into the textured macro-grooves.

12. The composite acetabular liner component according to claim 8, wherein the biocompatible thermoplastic backing member is comprised of ultra high molecular weight polyethylene, and wherein the macro-grooves are substantially radially positioned on the outer surface of the ceramic insert.

13. An acetabulum replacement system, comprising:

an acetabulum member operable to be positioned in an acetabulum;

a composite acetabular liner component, comprising;

a ceramic insert member having an inner surface and an outer surface; and

a biocompatible thermoplastic backing member molded onto the outer surface of the ceramic insert member when the biocompatible thermoplastic backing member is in a substantially softened state;

wherein the outer surface of the ceramic insert is provided with micro-roughness and a plurality of longitudinally positioned macro-grooves so as to increase the mechanical bonding between the biocompatible thermoplastic backing member and the outer surface of the ceramic liner member; and

a securing member operable to interconnect the acetabulum member and the composite acetabular liner component by fitting interaction with a structure in an outer surface of the biocompatible thermoplastic backing member.

14. The acetabulum replacement system of claim 13, wherein said securing member includes a deflectable ring positionable between said acetabulum member and said composite acetabular component.

15. The acetabulum replacement system of claim 14, at least one of said acetabulum member or said composite acetabular component define a groove to interact with at least a portion of said ring.

16. The acetabulum replacement system of claim 13, wherein said acetabulum member defines a groove on an inside thereof.

17. The acetabulum replacement system of claim 13, wherein said composite acetabular component defines a groove on an exterior thereof.

18. A hip replacement system, comprising:

an acetabulum member;

a composite acetabular component, comprising;

a ceramic insert member having an inner surface and an outer surface; and

a biocompatible thermoplastic backing member molded onto the outer surface of the ceramic insert member when the biocompatible thermoplastic backing member is in a substantially softened state;

wherein the outer surface of the ceramic insert is provided with micro-roughness and a plurality of longitudinally oriented macro-grooves so as to increase the mechanical bonding between the biocompatible thermoplastic backing member and the outer surface of the ceramic liner member;

a femoral component having a ball-shaped portion adapted to be received in the composite acetabular component; and

a securing member interconnecting the acetabulum member and the composite acetabular component by engaging an outer surface of the biocompatible thermoplastic backing member.

19. A method of making a composite acetabular component, comprising:

providing a ceramic insert member having an inner surface and an outer surface;

providing a biocompatible thermoplastic material;

imparting micro-roughness and a plurality of radially disposed and longitudinally oriented macro-grooves to the outer surface of the ceramic insert member;

softening the biocompatible thermoplastic material;

contacting the outer surface of the ceramic insert member with the softened biocompatible thermoplastic material for a sufficient period of time to form a biocompatible thermoplastic backing member onto the outer surface of the ceramic insert member; and

interconnecting the composite acetabular component with an acetabulum implant with an interconnecting member by fitting the interconnecting member in a structure in an outer surface of the biocompatible thermoplastic backing member;

wherein the micro-roughness and a plurality of radially disposed and longitudinally oriented macro-grooves of the outer surface of the ceramic insert member increases the mechanical bonding between the biocompatible thermoplastic backing member and the outer surface of the ceramic liner member.

20. The method according to claim 19, wherein the ceramic insert member has a substantially hemispherical shape.

21. The method according to claim 19, wherein the micro-roughness of a outer surface has an arithmetical mean roughness in a range of about 5 to about 10 microns.

22. The method according to claim 19, wherein the micro-roughness of a outer surface has a ten-point mean roughness in a range of about 50 to about 75 microns.

23. The method according to claim 19, wherein the biocompatible thermoplastic backing member has a substantially hemispherical shape.

24. The method according to claim 19, wherein the biocompatible thermoplastic backing member is comprised of polyethylene.

25. The method according to claim 19, wherein the biocompatible thermoplastic backing member is comprised of ultra high molecular weight polyethylene.