Method and apparatus for removing an acetabular bearing

• US 20080221699A1
• Filed: 03/07/2007
• Published: 09/11/2008
• Est. Priority Date: 03/07/2007
• Status: Active Grant

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Meridew, Jason D., Hershberger, Troy W.
• Granted Patent: US 7,572,294 B2
• Time in Patent Office: Days
• US Class Current: 623/22.29
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30403 Longitudinally-oriented cooperating ribs and grooves on mating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/30495 using a locking ring
• 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 2002/30822 Circumferential grooves
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3241 having a ring, e.g. for locking the femoral head into the acetabular cup
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/365 Connections of heads to necks
• CPC Class Codes: A61F 2002/4641 for disconnecting
• 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 2250/0024 made from both porous and non-porous parts, e.g. adjacent parts
• 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 2310/00401 : Coating made of iron, of stainless steel or of other Fe-based alloys
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00413 : Coating made of cobalt or of Co-based alloys

Abstract

A system for replacing a portion of a hip joint can include a cup having an outer surface and an inner surface. A bearing can include an outer bearing surface and an inner articulating surface. The outer bearing surface can be positioned adjacent to the cup. A ring can be selectively disposed between the cup and the bearing. The ring can define an annular body having a slit formed therein. A removal tool can define a proximal end and a distal end. The distal end can define a ring engaging surface and a bearing engaging surface. The ring engaging surface can be adapted to engage the ring at the slit such that the ring expands radially from a locked position away from engagement with the bearing to an unlocked position. The bearing engaging surface can be adapted to engage the bearing and urge the bearing away from the cup.

Claims

1. A system for replacing a portion of a hip joint comprising:

a cup having an outer surface and an inner surface, said outer surface engagable to an acetabulum;

a bearing having an outer bearing surface and an inner articulating surface, said outer bearing surface positioned adjacent said cup;

a ring selectively disposed between said cup and said bearing, said ring defining an annular body having a slit formed therein, said ring movable between a locked position wherein said ring retains said bearing relative to said cup and an unlocked position; and

a removal tool defining a proximal end and a distal end, said distal end defining a ring engaging surface and a bearing engaging surface, said-ring engaging surface adapted to engage said ring at said slit such that said ring expands radially from said locked position away from engagement with said bearing to said unlocked position, said bearing engaging surface adapted to engage said bearing and urge said bearing away from said cup.

2. The system of claim 1 wherein said cup defines an upper rim portion having a first slot formed radially thereon.

3. The system of claim 2 wherein said slot further defines a ramped surface sloping downward from an outboard portion to an inboard portion.

4. The system of claim 3 wherein said ring defines a pair of fingers formed at opposing portions of said slit, said fingers adapted to locate at said first slot in said cup in said locked position.

5. The system of claim 4 wherein said upper rim of said cup further defines a second slot formed therein and adapted to locate an annular protrusion defined on said ring in said locked position.

6. The system of claim 4 wherein said ring engaging surface of said removal tool defines a pair of sloped surfaces adapted to slidably engage said pair of fingers and thereby spread said ring radially toward said unlocked position.

7. The system of claim 4 wherein said distal end of said tool is accommodated by said ramped surface of said slot such that said bearing engaging surface engages said bearing.

8. The system of claim 4 wherein an upper portion of said bearing and said rim of said cup define complementary interlocking portions adapted to inhibit rotation of said bearing within said cup in said locked position.

9. The system of claim 1 wherein said distal end of said removal tool defines an angle relative to said proximal end of said tool wherein rotation of said removal tool at said proximal end imparts a prying action at said bearing engaging surface of said distal end onto said bearing.

10. The system of claim 1 wherein said distal end of said removal tool defines an engagement lip at said bearing engaging surface.

11. The system of claim 10 wherein said engagement lip is adapted to engage an underside surface of said bearing upon expansion of said ring to said unlocked position.

12. The system of claim 11 wherein said engagement lip imparts a force on said underside of said bearing upon movement of said removal tool away from said cup in a direction along a longitudinal axis of said removal tool.

13. A system for replacing a portion of a hip joint comprising:

a cup having a first surface engagable to an acetabulum and defining an upper rim portion having a first slot formed thereon, said slot formed from an outer face of said cup to an inboard portion of said cup;

a bearing having an outer surface positioned adjacent said cup and an inner articulating surface; and

a ring selectively disposed between said cup and said bearing and movable between a locked position wherein said ring retains said bearing relative to said cup and an unlocked position.

14. The system of claim 13 wherein said slot defines a ramped surface sloping downward from said outer face of said cup to said inboard portion.

15. The system of claim 13 wherein said ring defines an annular body having a slit formed therein.

16. The system of claim 15, further comprising a removal tool defining a proximal end and a distal end, said distal end defining a ring engaging surface and a bearing engaging surface, said ring engaging surface adapted to engage said ring at said slit such that said ring expands radially from said locked position away from engagement with said bearing to said unlocked position, said bearing engaging surface adapted to engage said bearing and urge said bearing away from said cup.

17. The system of claim 16 wherein said ring defines a pair of fingers formed at opposing portions of said slit, said fingers adapted to locate at said first slot in said cup in said locked position.

18. The system of claim 17 wherein said upper rim of said cup further defines a second slot formed therein and adapted to locate an annular protrusion defined on said ring in said locked position.

19. The system of claim 17 wherein said ring engaging surface of said removal tool defines a pair of sloped surfaces adapted to slidably engage said pair of fingers and thereby spread said ring radially toward said unlocked position.

20. The system of claim 17 wherein said distal end of said tool is accommodated by said ramped surface of said slot such that said bearing engaging surface engages said bearing.

21. The system of claim 17 wherein an upper portion of said bearing and said rim of said cup define complementary interlocking portions adapted to inhibit rotation of said bearing within said cup in said locked position.

22. The system of claim 13, further comprising a femoral component.

23. A system for replacing a portion of a hip joint comprising:

a cup having a first surface engagable to an acetabulum and defining an upper rim portion having a slot formed therein;

a bearing having an outer surface positioned adjacent said cup and an inner articulating surface; and

a ring selectively disposed between said cup and said bearing and movable between a locked position wherein said ring retains said bearing relative to said cup and an unlocked position, said ring defining an annular protrusion adapted to locate in said slot and inhibit rotation of said ring in said locked position.

24. The system of claim 23 wherein said upper rim portion further defines a continuous outer rim portion and wherein said slot is formed inboard of said continuous outer rim portion.

25. The system of claim 24 wherein said cup further defines an opposing slot formed on said upper rim, said opposing slot defining a stepped surface positioned inboard of said continuous outer rim portion and wherein said ring defines a pair of fingers formed at opposing portions of a slit formed in said ring, said pair of fingers locating at said opposing slot.

26. The system of claim 25, further comprising a removal tool defining a proximal end and a distal end, said distal end defining a ring engaging surface and a bearing engaging surface, said ring engaging surface adapted to engage said ring at said slit such that said ring expands radially from said locked position away from engagement with said bearing to said unlocked position, said bearing engaging surface adapted to engage said bearing and urge said bearing away from said cup.