Hip joint prosthesis with integral bearing extraction member

• US 6,488,713 B1
• Filed: 04/25/2001
• Issued: 12/03/2002
• Est. Priority Date: 04/25/2001
• Status: Expired due to Term

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Hershberger, Troy W.
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US09/842,499
• Time in Patent Office: 587 Days
• Field of Search: 623/22.1, 623/22.11, 623/16.11, 623/18.11, 623/22.38, 623/22.24, 623/22.31
• US Class Current: 623/22.11
• CPC Class Codes: A61B 17/1746 for the acetabulum
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30477 using sharp protrusions, e.g. spikes, for anchoring into connecting prosthetic part
• CPC Class Codes: A61F 2002/30487 Circumferential cooperating grooves and beads on cooperating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/3069 Revision endoprostheses
• CPC Class Codes: A61F 2002/30733 Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30795 Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30973 Two joined adjacent layers having complementary interlocking protrusions and recesses
• CPC Class Codes: A61F 2002/3403 Polar aperture
• CPC Class Codes: A61F 2002/3493 Spherical shell significantly greater than a hemisphere, e.g. extending over more than 200 degrees
• CPC Class Codes: A61F 2002/4641 : for disconnecting
• 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 2230/0017 : Angular shapes
• 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

Abstract

A hip joint prosthesis having a retainer for a modular bearing in an acetabular cup and also having a bearing extraction member mounted in the cup for removal of a primary bearing. One embodiment of the bearing extraction member is a plug which is located in a hole provided in the acetabular cup and which is covered by a polyethylene bearing directly molded into the cup. The plug is an internally threaded plug with a convex head and is adapted to be pulled out of its resting position in the cup with the aid of an extraction tool such that the head of the plug exerts a removal force on the molded polyethylene bearing, causing it to disengage from the cup.

Claims

1. A hip joint prosthesis with an integral bearing extraction member, comprising:

an acetabular cup having a modular bearing retainer;

a primary bearing direct compression molded to said acetabular cup; and

implantable means for removing said molded primary bearing from said acetabular cup substantially in one piece without disturbing said acetabular cup.

2. The prosthesis of claim 1, wherein said removing means includes a plug mounted in said acetabular cup, and wherein said primary bearing is directly molded over said plug.

3. The prosthesis of claim 2, wherein said plug is internally threaded.

4. The prosthesis of claim 3, wherein said primary bearing is molded into said internally threaded plug.

5. A hip joint prosthesis with an integral bearing extraction member, comprising:

an acetabular cup;

a bearing extraction member mounted in said acetabular cup, said bearing extraction member including an opening therein for engaging an extraction tool to be inserted during a revision procedure; and

a primary bearing direct compression molded into said acetabular cup and into said opening in said bearing extraction member.

6. The prosthesis of claim 5, wherein said bearing extraction member is recessed in said acetabular cup.

7. The prosthesis of claim 6, wherein said bearing extraction member includes a plug positioned in a hole in said acetabular cup, and wherein said primary bearing is directly molded over said plug.

8. The prosthesis of claim 5, wherein said bearing extraction member is internally threaded.

9. The prosthesis of claim 7, wherein said acetabular cup has a surface defining a retainer for a modular bearing.

10. A hip joint prosthesis with an integral bearing extraction member, comprising:

an acetabular cup having a modular bearing retainer adapted to cooperate with an auxiliary mechanical locking element to securely retain a modular bearing in said acetabular cup;

a primary bearing direct compression molded to said acetabular cup; and

implantable means for removing said primary bearing from said acetabular cup substantially in one piece without disturbing said acetabular cup.

11. A hip joint prosthesis with an integral bearing extraction member, comprising:

an acetabular cup;

a primary bearing secured to said acetabular cup; and

a bearing extraction member mounted in said acetabular cup in contact with said primary bearing,

wherein said bearing extraction member is recessed in said acetabular cup, wherein said bearing extraction member includes a ring, and wherein said primary bearing is directly molded over said ring.

12. A method of replacing a hip joint, comprising:

providing an acetabular cup with a retainer for a modular replacement bearing to be secured to said acetabular cup after removal of a primary bearing therefrom;

providing a bearing extraction member in said acetabular cup;

direct compression molding a primary bearing to said acetabular cup; and

implanting said acetabular cup, with said retainer, primary bearing and bearing extraction member, in a patient during primary hip replacement surgery.

13. A method of replacing a hip joint, comprising:

providing an acetabular cup with a retainer for a modular replacement bearing to be secured to said acetabular cup after removal of a primary bearing therefrom;

providing a bearing extraction member in said acetabular cup;

securing a primary bearing to said acetabular cup;

implanting said acetabular cup, with said retainer, primary bearing and bearing extraction member, in a patient during primary hip replacement surgery;

removing said primary bearing during revision surgery without removing said acetabular cup; and

securing a modular bearing to said retainer during said revision surgery.

14. A method of replacing a hip joint, comprising:

providing a bearing extraction member in an acetabular cup;

direct compression molding a primary bearing to said acetabular cup; and

implanting said acetabular cup, with said bearing extraction member and said primary bearing therein, in a patient during primary hip replacement surgery.

15. A method of replacing a hip joint, comprising:

providing a bearing extraction member in an acetabular cup;

securing a primary bearing to said acetabular cup;

implanting said acetabular cup, with said bearing extraction member and said primary bearing therein, in a patient during primary hip replacement surgery;

attaching an extraction tool to said bearing extraction member;

actuating said bearing extraction member with said extraction tool to extract said primary bearing from said acetabular cup; and

securing a secondary bearing to said acetabular cup after removal of said primary bearing therefrom.

16. A hip joint replacement system, comprising:

an acetabular cup;

a primary bearing secured to said acetabular cup;

a bearing extraction member mounted in said acetabular cup in contact with said primary bearing; and

extraction instrumentation including means for engaging said bearing extraction member and means for engaging said acetabular cup at a point spaced from said bearing extraction member.

17. The hip joint replacement system of claim 16, wherein said means for engaging said bearing extraction member and said means for engaging said acetabular cup are mechanically interconnected.