METHOD FOR MAKING A METAL-BACKED ACETABULAR IMPLANT

• US 20090088866A1
• Filed: 12/09/2008
• Published: 04/02/2009
• Est. Priority Date: 04/12/2005
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Case, Kirt L.
• Granted Patent: US 7,794,504 B2
• Time in Patent Office: Days
• US Class Current: 623/22.210
• 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 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/30345 Multiple conical connection, i.e. the protrusion and recess having several tapered sections of different complementary conicities
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30487 Circumferential cooperating grooves and beads on cooperating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/3054 about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30906 shot- sand- or grit-blasted
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/3437 oriented inwardly towards the shell centre line
• CPC Class Codes: A61F 2002/3448 Multiple cups made of three or more concentric shells fitted or nested into one another
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/4653 using cooling means
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• 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: B29C 43/003 : characterised by the choice of material
• CPC Class Codes: B29L 2031/7532 : Artificial members, protheses
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A metal-backed acetabular implant and a method of forming the same.

Claims

1. An acetabular implant comprising:

a shell having an outer shell surface and an inner shell surface, the outer shell surface configured to contact bone;

an integument having an outer integument surface and an inner integument surface, the outer integument surface configured to couple to the inner shell surface; and

a plastic bearing having an outer bearing surface and an inner bearing surface, the inner bearing surface defining a socket, the inner integument surface configured to form a friction-fit with the outer bearing surface.

2. The acetabular implant of claim 1, wherein the plastic bearing comprises ultra high molecular weight polyethylene.

3. The acetabular implant of claim 1, wherein the inner integument surface defines an annular female taper and the outer bearing surface defines an annular male taper configured to taper couple to the annular female taper of the inner integument surface.

4. The acetabular implant of claim 1, further comprising a longitudinal axis, wherein the inner integument surface comprises a base centered about the longitudinal axis and extending substantially perpendicular to the longitudinal axis.

5. The acetabular implant of claim 4, wherein the outer bearing surface comprises a second base centered about the longitudinal axis and extending substantially perpendicular to the longitudinal axis, the second base of the bearing sized to engage the base of the integument.

6. The acetabular implant of claim 4, wherein the inner integument surface further comprises a first taper portion and a second taper portion, the first taper portion extending from the base of the integument at a first angle relative to the longitudinal axis and the second taper portion extending from the first taper portion at a second angle relative to the longitudinal axis, the first angle exceeding the second angle.

7. The acetabular implant of claim 4, wherein the inner integument surface further comprises a first taper portion and a second taper portion, the first taper portion extending a first distance from the base of the integument and the second taper portion extending a second distance from the first taper portion, the second distance exceeding the first distance.

8. The acetabular implant of claim 1, further comprising a longitudinal axis, wherein the integument includes an annular rim and the inner integument surface includes a first taper portion and a second taper portion, the first taper portion extending from the annular rim at a first angle relative to the longitudinal axis and the second taper portion extending from the first taper portion at a second angle relative to the longitudinal axis, the second angle exceeding the first angle.

9. The acetabular implant of claim 1, wherein the integument includes an annular rim and the inner integument surface includes a first taper portion and a second taper portion, the first taper portion extending a first distance from the annular rim and the second taper portion extending a second distance from the first taper portion, the first distance exceeding the second distance.

10. The acetabular implant of claim 1, wherein the inner shell surface defines an annular female taper and the outer integument surface defines an annular male taper configured to taper couple to the annular female taper of the inner shell surface.

11. The acetabular implant of claim 1, wherein:

the integument comprises a first annular rim having a flange that projects from the first annular rim; and

the bearing comprises a second annular rim having a groove configured to receive the flange of the integument.

12. An acetabular implant comprising:

a shell configured to contact bone;

a plastic bearing defining a socket; and

an integument positionable between the shell and the bearing, the integument configured to form a friction-fit with the bearing.

13. The acetabular implant of claim 12, wherein the plastic bearing comprises ultra high molecular weight polyethylene.

14. The acetabular implant of claim 12, wherein the bearing defines an annular male taper and the integument defines an annular female taper configured to taper couple to the annular male taper of the bearing.

15. The acetabular implant of claim 12, further comprising a longitudinal axis, wherein the integument comprises a base centered about the longitudinal axis and extending substantially perpendicular to the longitudinal axis.

16. The acetabular implant of claim 15, wherein the bearing comprises a second base centered about the longitudinal axis and extending substantially perpendicular to the longitudinal axis, the second base of the bearing sized to engage the base of the integument.

17. The acetabular implant of claim 15, wherein the integument further comprises a first taper portion and a second taper portion, the first taper portion extending from the base of the integument at a first angle relative to the longitudinal axis and the second taper portion extending from the first taper portion at a second angle relative to the longitudinal axis, the first angle exceeding the second angle.

18. The acetabular implant of claim 15, wherein the integument further comprises a first taper portion and a second taper portion, the first taper portion extending a first distance from the base of the integument and the second taper portion extending a second distance from the first taper portion, the second distance exceeding the first distance.

19. The acetabular implant of claim 12, further comprising a longitudinal axis, wherein the integument includes an annular rim, a first taper portion, and a second taper portion, the first taper portion extending from the annular rim at a first angle relative to the longitudinal axis and the second taper portion extending from the first taper portion at a second angle relative to the longitudinal axis, the second angle exceeding the first angle.

20. The acetabular implant of claim 12, wherein the integument includes an annular rim, a first taper portion, and a second taper portion, the first taper portion extending a first distance from the annular rim and the second taper portion extending a second distance from the first taper portion, the first distance exceeding the second distance.

21. The acetabular implant of claim 12, wherein the shell defines an annular female taper and the integument defines an annular male taper configured to taper couple to the annular female taper of the shell.

22. The acetabular implant of claim 12, wherein:

the integument comprises a first annular rim having a flange that projects from the first annular rim; and

the bearing comprises a second annular rim having a groove configured to receive the flange of the integument.

23. A method of forming a metal-backed acetabular implant, comprising the steps of:

providing a plastic bearing having an outer bearing surface and an inner bearing surface defining a socket;

providing an integument having an outer integument surface and an inner integument surface;

forming a sub-assembly by friction-fitting the outer bearing surface to the inner integument surface;

providing a shell; and

forming an implant by coupling the shell and the sub-assembly.

24. The method of claim 23, further comprising the step of cooling the bearing before forming the sub-assembly.

25. The method of claim 23, wherein the step of forming the sub-assembly comprises taper coupling the bearing to the integument.

26. The method of claim 23, wherein the step of forming the sub-assembly comprises press-fitting the bearing into the integument.

27. The method of claim 23, wherein the step of forming the implant comprises taper coupling the integument to the shell.

28. The method of claim 23, further comprising the step of implanting the shell into a patient before coupling the sub-assembly to the shell.