Prosthetic acetabular cup and method of manufacture

• US 20070191962A1
• Filed: 04/16/2007
• Published: 08/16/2007
• Est. Priority Date: 10/12/2004
• Status: Abandoned Application

• Current Assignee: Benoist Girard SAS (Stryker Corporation)
• Original Assignee: Benoist Girard SAS (Stryker Corporation)
• Inventors: Jones, Eric, Raugel, Patrick, Rushton, Neil, Field, Richard
• Application Number:
  US11/787,563
• Publication Number:
  US 20070191962A1
• Time in Patent Office: Days
• US Class Current: 623/22.24
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/30934 Special articulating surfaces
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3097 using laser
• CPC Class Codes: A61F 2002/3412 with pins or protrusions, e.g. non-sharp pins or protrusions projecting from a shell surface
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0024 made from both porous and non-porous parts, e.g. adjacent parts
• CPC Class Codes: A61F 2250/0098 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00407 Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00491 Coating made of niobium or Nb-based alloys
• CPC Class Codes: A61F 2310/00544 Coating made of tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF
• CPC Class Codes: A61L 27/443 : with carbon fillers
• CPC Class Codes: C08L 71/12 : Polyphenylene oxides

Abstract

A prosthetic bearing element and a method for forming the same includes an injection molded bearing made of PEEK resin with short carbon fiber reinforcement. The inner surface of the PEEK bearing is adapted to receive a ceramic or metal articulation component. The outer surface of the bearing layer includes sputtered titanium particles forming a porous backing layer. Hydroxyapatite is then sputtered or otherwise deposited onto the titanium backing layer to form an outer surface of the prosthetic bearing element. A barrier layer can be formed either of PEEK or titanium which layer is between the outer surface of the molded bearing and the inner surface of the porous structure. The barrier layer prevents tissue ingrowth into the bearing component. Hydroxyapatite is then sputtered onto the outer porous layer or applied by solution deposition. This outer surface of the prosthetic bearing element can then be coated with bone morphogenic protein.

Claims

1. A method of forming a prosthetic bearing element comprising:

injection molding a bearing layer of PEEK resin having 20 to 40% carbon fiber to form an inner bearing surface;

sputtering metal particles on an outer non-bearing surface of said molded bearing to form a porous backing layer; and

sputtering hydroxyapatite onto the metal backing layer to form an outer surface of the prosthetic bearing element.

2. The method as set forth in claim 1 further comprising plasma spraying PEEK on the outer surface of the bearing layer prior to applying the metal layer.

3. The method as set forth in claim 1 wherein the metal particle size is varied to form an interconnected porosity which increases towards the outer surface as the layer is built up.

4. The method as set forth in claim 3 wherein the particle size increases from smaller to larger to form the increasing interconnected porosity.

5. The method as set forth in claim 1 wherein a mixture of metal and hydroxyapatite particles is sputtered onto the backing layer.

6. The method as set forth in claim 1 wherein the bearing layer has about 30% short carbon fibers.

7. The method as set forth in claim 1 further comprising a metal backing between the PEEK bearing and the porous metal layer for blocking tissue ingrowth beyond the porous metal layer.

21. The prosthetic acetabular cup as set forth in claim 1 wherein the metal is selected from the group consisting of titanium, tantalum, titanium alloy, cobalt chrome alloy or niobium.

8. A prosthetic acetabular cup comprising a bearing surface layer made from a composite material which includes PEEK resin and at least 20% to 40% short carbon fibers, and a backing layer or layers to provide a barrier and/or porosity and/or roughness.

9. The prosthetic acetabular cup as set forth in claim 8 in which the backing layer is made from metal.

10. The prosthetic acetabular cup as set forth in claim 9 in which the metal is selected from the group consisting of titanium, tantalum, titanium alloy, cobalt chrome alloy or niobium.

11. The prosthetic acetabular cup as set forth in claim 8 in which the backing layer is made from pure PEEK resin to produce a barrier between the composite material or the surface layer and the bone cells in which it will be used.

12. The prosthetic acetabular cup as set forth in claim 8 in which the backing layer is coated with a bioactive material.

13. The prosthetic acetabular cup as set forth in claim 12 in which the bioactive material is hydroxyapatite (HAP) and/or bone morphogenic proteins (BMP).

14. A method of making an acetabular cup comprising forming a bearing surface layer from a composite material including PEEK resin and at least 20% to 40% short carbon fibers;

forming a backing layer or layers over said bearing surface to provide a barrier and/or porosity and/or roughness, and coating the backing layer with a bioactive material.

15. The method as set forth in claim 14 wherein the backing layer is applied after forming the bearing surface layer.

16. The method as set forth in claim 14 wherein the backing layer is formed first and the inner bearing layer is subsequently applied to the backing layer.

17. The method as set forth in claim 14 further comprising preforming the bearing surface layer and applying the backing layer or layers by sputtering and/or chemical deposition.

18. The method as set forth in claim 14 further comprising preforming the backing layer and providing the inner bearing surface layer by molding.

19. The method as set forth in claim 14 further comprising a backing layer the porosity of which varies from its inner to its outer sides to form an outer porous surface.

20. The method as set forth in claim 14 further comprising applying the bioactive material by sputtering or chemical deposition.