Patellar implants

Patent metadata

Field	Value
Publication number	US-9801974-B2
Application number	US-201113816852-A
Country	US
Kind code	B2
Filing date	Aug 12, 2011
Priority date	Aug 13, 2010
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A patellar implant is provided being of a two part construction having a strong base portion 32, 54, 72 and 92 (manufactured from a metal material or other medical grade strong material) with a molder outer material 34, 62, 80 and 100 (manufactured from a polymeric material or other softer, smoother material) at least on one side to provide a smooth friction surface to contact the femoral portion of a patient's knee.

First claim

What is claimed is:

1. A patellar implant for implantation into a patient's natural patella adjacent a femoral implant component, the patellar implant comprising:
a base portion made from a medical grade material having a sufficient rigidity to prevent bending when positioned within a patient's natural patella, the base portion comprising a porous metallic material having a porous top surface and a porous bottom surface;
a polymeric portion made from a polymeric material positioned about a portion of the base portion and adapted to bear against a femoral component; and
a membrane embedded between the base portion and the polymeric portion to provide a barrier between the porous metallic material and the polymer material; and
wherein the embedded membrane is positioned in contact with both the porous top surface of the base portion and the polymer material of the polymeric portion.

2. The patellar implant of claim 1 , wherein the bottom surface of the base has an attachment peg extending therefrom.

3. The patellar implant of claim 2 , wherein said base has a plurality of said attachment pegs depending from said bottom surface, the pegs being porous to allow for the boney ingrowth of a patient's natural bone.

4. The patellar implant of claim 3 , wherein the attachment pegs are provided with a porous coating to allow for tissue ingrowth when positioned within a patient's natural patella.

5. The patellar implant of claim 2 , wherein the base is provided with a plurality of indentations about its periphery to allow for additional polymeric material of the polymeric portion to flow about the periphery to fully bond the polymeric portion to the base portion.

6. The patellar implant of claim 1 , wherein the polymeric portion is molded about the base portion with the polymeric portion extending about sides of the base portion to provide a dovetail lock between the polymeric portion and the base portion.

7. The patellar implant of claim 1 , wherein the base portion is provided with a pair of indentions provided about its periphery generally opposite each other to allow for additional polymeric material of the polymeric portion to fill in the area of the indentations to provide greater flexibility to the patellar implant.

8. The patellar implant of claim 7 , wherein said indentations are positioned on superior and inferior poles of the patellar implant when positioned with respect to a patient's natural knee cap and the femoral component.

9. The patellar implant of claim 1 , wherein the base portion is made of a material selected from the group consisting of titanium, titanium alloy, zirconium, chrome cobalt, stainless steel and ceramic, the material having a rigidity appropriate to prevent bending when positioned within a patient's natural patella.

10. The patellar implant of claim 1 , wherein the polymeric portion is made of a polyethylene material or a cross-linked polyethylene material.

11. The patellar implant of claim 1 , wherein the membrane comprises an impermeable barrier layer between the porous metallic material of the base portion and the polymer material of the polymeric portion.

12. The patellar implant of claim 1 , wherein the membrane is embedded in the porous metallic material of the base portion.

13. A patellar implant for implantation into a patient's natural patella adjacent a femoral implant component, the patellar implant comprising:
a base portion made from a medical grade material having a sufficient rigidity to prevent bending when positioned within a patient's natural patella, wherein said base portion comprises a base having a top surface, a side surface, and a bottom surface;
a polymeric portion made from a polymeric material positioned about a portion of the base portion and adapted to bear against a femoral component; and
a plurality of attachment pegs depending from the bottom surface of the base, the pegs being porous to allow for the boney ingrowth of a patient's natural bone, and the polymeric portion being attached to the top surface of the base; and
wherein a thin impermeable membrane is applied about portions of the attachment pegs to prevent boney tissue ingrowth along sides of the attachment pegs while allowing such boney tissue ingrowth at a bottom surface of said attachment pegs to allow for easier removal of the patellar implant in a revision surgery.

14. A patellar implant for implantation into a patient's natural patella adjacent a femoral implant component, the patellar implant comprising:
a base portion made entirely from a porous metallic material having a sufficient rigidity to prevent bending of the base portion when attached to a patient's natural patella, the base portion having a porous top surface and a porous bottom surface;
a polymeric portion made from a polymeric material, the polymeric portion positioned about a portion of the base portion and adapted to bear against a femoral component; and
a membrane embedded between the base portion and the polymeric portion to provide a barrier between the porous metallic material and the polymer material, and wherein the porous bottom surface of the base portion facilitates boney tissue ingrowth into the base portion; and
wherein the embedded membrane is positioned in contact with both the porous top surface of the base portion and the polymer material of the polymeric portion.

15. The patellar implant of claim 14 , wherein the polymeric portion encapsulates the porous top surface of the base portion.

16. The patellar implant of claim 14 , wherein the base portion further includes one or more attachment pegs extending from the bottom surface.

17. The patellar implant of claim 16 , wherein a side surface of the base portion and an inner surface of the polymeric portion together define a dovetail lock therebetween to retain the polymeric portion on the base portion.

18. The patellar implant of claim 16 , further comprising a thin impermeable membrane extending about a periphery of the attachment pegs to prevent boney tissue ingrowth into the sides of the attachment pegs while allowing boney tissue ingrowth into a bottom surface of the attachment pegs.

19. The patellar implant of claim 14 , wherein the periphery of the base portion is provided with a pair of indentions arranged generally opposite one another with the polymer material of the polymeric portion positioned within the indentations to provide increased flexibility to the patellar implant.

20. The patellar implant of claim 14 , wherein the membrane comprises an impermeable barrier layer between the porous metallic material of the base portion and the polymer material of the polymeric portion.

21. The patellar implant of claim 14 , wherein the membrane is embedded in the porous metallic material of the base portion.

Assignees

• Landon Ryan Lloyd
• Smith & Nephew Inc

Inventors

• Landon Ryan Lloyd

Classifications

• A61F2310/00017

  Iron- or Fe-based alloys, e.g. stainless steel · CPC title

• A61F2310/00023

  Titanium or titanium-based alloys, e.g. Ti-Ni alloys · CPC title

• A61F2002/30892

  parallel · CPC title

• A61F2310/00029

  Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium · CPC title

• A61F2/3877

  Patellae or trochleae · CPC title