Coated orthopaedic implant components

• US 5,980,974 A
• Filed: 04/16/1996
• Issued: 11/09/1999
• Est. Priority Date: 01/19/1996
• Status: Expired due to Fees

• Current Assignee: Implant Sciences Corporation
• Original Assignee: Implant Sciences Corporation
• Inventors: Bunker, Stephen N., Armini, Anthony J.
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US08/633,117
• Time in Patent Office: 1,302 Days
• Field of Search: 427/2.26, 427/2.27, 427/526, 427/527, 427/529, 427/528, 427/531, 623/16, 623/18, 623/23, 606/76
• US Class Current: 427/2.27
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2002/30685 Means for reducing or preventing the generation of wear particulates
• 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 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00502 Coating made of ruthenium or Ru-based alloys
• CPC Class Codes: A61F 2310/00508 Coating made of rhodium or Rh-based alloys
• CPC Class Codes: A61F 2310/00514 Coating made of palladium or Pd-based alloys
• CPC Class Codes: A61F 2310/00556 Coating made of iridium or Ir-based alloys
• CPC Class Codes: A61F 2310/00562 Coating made of platinum or Pt-based alloys
• CPC Class Codes: A61F 2310/00634 Coating made of zirconium oxide or hydroxides
• CPC Class Codes: A61L 27/306 Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: Y10S 623/923 Bone

Abstract

An improved coated orthopaedic implant component is disclosed. The implant may be coated with platinum, iridium or other metals for improved characteristics. Ion beam coating orthopaedic parts by ion implanting the parts with zirconium ions while the parts are immersed in an oxygen-containing background gas is also disclosed. The adhesion of the graded interface zirconium oxide surface layer so formed is further improved by the initial removal of surface contamination using an ion bombardment and the deposition of an intermediate layer of platinum or similar metal or silicon between the orthopaedic metal component and the zirconium oxide. Furnace heating results in atomic interdiffusion to enhance adhesion between the surfaces. The zirconium oxide provides a low friction, low wear articulating surface. The graded interface may be characterized by a blackish color and a transition between pure zirconium oxide and pure intermediate layer that extends over a thickness of hundreds of Angstroms. In an alternative embodiment, the thickness of the zirconium oxide coating may be increased by also adding a simultaneous deposition of zirconium oxide on the parts.

Claims

1. A process for treating an articulating surface of a metallic femoral component of an orthopaedic implant, comprising steps of:

(a) depositing on the articulating surface of the component an adhesion coating of a platinum group metal selected from the group consisting of platinum, iridium, ruthenium, rhodium, palladium and alloys thereof;

(b) heating the component under conditions sufficient to cause atomic interdiffusion of the adhesion coating into the metallic component thereby forming a first graded interface between the articulating surface and the adhesion coating;

(c) immersing the component in an oxygen-containing gas; and

(d) exposing the immersed component to an ion beam of zirconium under conditions sufficient to form a zirconium oxide coating on said adhesion coating.

2. The process of claim 1, further comprising a step of:

simultaneously with step (d), exposing the immersed component to a flux of zirconium atoms.

4. The process of claim 1, wherein the partial pressure of said oxygen-containing gas is in a range from 5×

10^-6 to 1×

10^-3 Torr.

5. A metal femoral component produced by the process of claim 1.

6. The process of claim 1 wherein the adhesion coating is selected from the group consisting of platinum, iridium and a platinum-iridium alloy.

3. The process of claim wherein:

step (b) comprises heating the metallic femoral component at a temperature between about 100°

C. and 1000°

C. for at least 10 minutes.