PROSTHESIS FOR CEMENTED FIXATION AND METHOD FOR MAKING THE PROSTHESIS

• US 20110106268A1
• Filed: 10/14/2010
• Published: 05/05/2011
• Est. Priority Date: 10/30/2009
• Status: Active Grant

• Current Assignee: Depuy Ireland Unlimited Company (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: DEFFENBAUGH, DAREN L., ZANNIS, ANTHONY D.
• Granted Patent: US 8,715,359 B2
• Time in Patent Office: Days
• US Class Current: 623/20.32
• CPC Class Codes: A61B 17/14 Surgical saws A61B17/1637 takes precedence; tooth saws A61C3/12 ; Accessories therefor
• CPC Class Codes: A61F 2/3836 Special connection between upper and lower leg, e.g. constrained
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4202 for ankles
• CPC Class Codes: A61F 2002/30321 differing in roughness
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30967 Diffusion bonding
• CPC Class Codes: A61F 2002/4619 for extraction
• CPC Class Codes: A61F 2250/0025 differing in roughness
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

A joint prosthesis system is suitable for cemented fixation. The system has two metal implant components and a bearing. One of the metal implant components has an articulation surface for articulation with the bearing. The other metal implant component has a mounting surface for supporting the bearing. One of the metal implant components includes an extension, such as a stem or pegs, with an exposed outer surface. The metal implant component from which the extension extends comprises titanium and the exposed outer surface of the extension comprises a different form of titanium. A method of making the joint prosthesis is also disclosed.

Claims

1. A joint prosthesis comprising:

a first metal component having a solid metal articulation surface and a bone-engaging surface;

a bearing having an articulation surface shaped to bear against the articulation surface of the first metal component and an opposite surface;

a second metal component having a solid metal mounting surface and an opposite bone-engaging surface; and

an extension extending out from a junction with the bone-engaging surface of one of the metal components to an exposed end, the extension having an exposed outer surface;

wherein;

the extension is configured for stabilizing the metal component when implanted in a bone of a patient;

wherein the solid metal portion of the metal component from which the extension extends comprises titanium; and

the exposed outer surface of the extension comprises a different form of titanium.

2. The joint prosthesis of claim 1 wherein the first metal component and second metal component include a titanium alloy and the extension comprises commercially pure titanium.

3. The joint prosthesis of claim 2 wherein the exposed outer surface of the extension comprises porous titanium.

4. The joint prosthesis of claim 3 wherein the extension comprises titanium foam.

5. The joint prosthesis of claim 4 wherein the extension has a thickness at the junction and the extension consists of titanium foam across the entire thickness of the extension at the junction.

6. The joint prosthesis of claim 5 wherein at least part of the extension has a void space of at least 65% by volume.

7. The joint prosthesis of claim 5 wherein the exposed outer surface of the extension at the end of the extension has a different roughness than at least a part of the exposed outer surface of the extension between the end and the junction.

8. The joint prosthesis of claim 5 wherein the extension is selected from the group consisting of a peg and a stem.

9. The joint prosthesis of claim 8 wherein the bone-engaging surface of at least one of the metal components comprises porous metal.

10. The joint prosthesis of claim 9 wherein the porous metal comprises commercially pure titanium.

11. The joint prosthesis of claim 5 wherein:

the prosthesis is an ankle prosthesis;

the first metal component comprises a distal tibial component; and

the extension extends out from the bone-engaging surface of the distal tibial component.

12. The joint prosthesis of claim 5 wherein:

the prosthesis is a knee prosthesis;

the first metal component is a distal femoral component configured to replace the distal end of the femur; and

the second metal component is a tibial tray configured to replace the proximal end of the tibia.

13. The joint prosthesis of claim 12 wherein:

the mounting surface of the tibial tray comprises solid titanium alloy, the solid titanium alloy extending from the mounting surface toward the bone-engaging surface;

the extension comprises a foam of commercially pure titanium; and

the extension is bonded to the solid titanium alloy of the tibial tray by sintering.

14. The joint prosthesis of claim 13 wherein the bone-engaging surface of the tibial tray comprises commercially pure titanium foam bonded to the solid titanium alloy of the tibial tray by sintering.

15. The joint prosthesis of claim 12 wherein:

the articulating surface of the femoral component comprises solid titanium alloy, the solid titanium alloy extending from the articulating surface toward the bone-engaging surface;

the extension comprises a foam of commercially pure titanium; and

the extension is bonded to the solid titanium alloy of the femoral component by sintering.

16. The joint prosthesis of claim 15 wherein the bone-engaging surface of the femoral component comprises commercially pure titanium foam bonded to the solid titanium alloy of the femoral component by sintering.

17. A method of making an orthopaedic implant component comprising the steps of:

providing a solid metal base having a first surface and a second surface opposite to the first surface;

providing a porous metal extension to be assembled with the solid metal base;

wherein the porous metal extension and the second surface of the solid metal base include complementary mounting structures for assembling the porous metal extension and the solid metal base;

assembling the porous metal extension and the base; and

sintering the assembly of the porous metal extension and the base to bond the porous metal extension to the base.

18. The method of claim 17 further comprising the step of providing a porous metal preform having a shape different than the shape of the porous metal extension.

19. The method of claim 18 further comprising the step of placing the porous metal preform against the second surface of the base and sintering the preform to the base.

20. The method of claim 19 wherein the porous metal extension and the porous metal preform are integral and the steps of assembling the porous metal extension and the base and placing the porous metal preform against the second surface of the base are performed simultaneously.

21. The method of claim 19 wherein the porous metal extension and the porous metal preform are discrete components and the steps of assembling the porous metal extension and the base and placing the porous metal preform against the second surface of the base are performed separately.