Method and apparatus for use of porous implants

• US 7,597,715 B2
• Filed: 02/17/2006
• Issued: 10/06/2009
• Est. Priority Date: 04/21/2005
• 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, Brown, David R, Hershberger, Troy W, Ronk, Robert M
• Primary Examiner(s): Willse; David H
• Assistant Examiner(s): Blanco; Javier G
• Application Number:
  US11/357,868
• Publication Number:
  US 20060241781A1
• Time in Patent Office: 1,327 Days
• Field of Search: 623/22.21, 623/22.24, 623/22.33, 623/22.34, 623/22.37, 623/22.38, 623/23.53, 623/23.55
• US Class Current: 623/22.32
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/4609 of acetabular cups
• CPC Class Codes: A61F 2002/30535 Special structural features of bone or joint prostheses not otherwise provided for
• CPC Class Codes: A61F 2250/0058 Additional features; Implant or prostheses properties not otherwise provided for

Abstract

An orthopedic prosthesis for implantation into a bone of a patient includes a porous metal shell adapted to be affixed within the bone. The porous metal shell includes an outer surface adapted to receive bone ingrowth and an inner surface adapted to engage a liner. The porous metal shell is porous from the outer surface to the inner surface. A non-porous member may be affixed to the porous metal shell. The non-porous member may include a piercing member extending from the outer surface, the piercing member adapted to penetrate the bone in an implanted position. The non-porous member may include spikes or fins. In one example, the piercing member may define a reduced material cross section at an interface with the outer surface of the porous metal shell. The piercing member may be adapted to be broken at the reduced material cross section and removed from the porous metal shell.

Claims

1. An orthopedic prosthesis comprising a hemispherical body that includes an open end defining a perimeter, said orthopedic prosthesis being formed of a porous metal shell, a non-porous rim defined at a radial edge of said porous metal shell and being metallurgically bonded to said porous metal shell such that said non-porous rim is non-removable from said porous metal shell, and a bearing liner separately formed from and insertable through said non-porous rim to a position against an inner bearing engaging surface of said porous metal shell, said porous metal shell defining continuous porous metal from said inner bearing engaging surface to an outer bone engaging surface, and defining a first annular pocket around said perimeter of said hemispherical body, said non-porous rim including a first annular collar formed around said perimeter that is received by said first annular pocket creating an overhanging interlock between said porous metal shell and said non-porous rim entirely around said perimeter,

wherein said non-porous rim defines a second annular pocket around said perimeter that receives a second annular collar formed around said porous metal shell,

wherein said non-porous rim includes at least one raised wall and an outer face that includes a planar surface, said at least one raised wall integrally formed with said non-porous rim and extending upright to a position laterally offset from said planar surface, said at least one raised wall adapted to mate with an attachment tool.

2. The orthopedic prosthesis of claim 1 wherein said at least one raised wall defines a tapered cross-section adapted to securably mate with a complementary tapered cross-section defined on said attachment tool.

3. The orthopedic prosthesis of claim 2 wherein said at least one raised wall comprises a pair of diametrically opposed raised walls integrally formed with said non-porous rim.

4. The orthopedic prosthesis of claim 3 wherein said pair of diametrically opposed raised walls do not extend inboard of an outermost diameter of said bearing engaging surface.

5. The orthopedic prosthesis of claim 3 wherein said non-porous rim does not extend inboard of an outermost diameter of said bearing engaging surface.

6. The orthopedic prosthesis of claim 4, further comprising:

an annular ring selectively located within an annular groove formed on an

inner surface of the non-porous rim, said annular ring capturing said bearing liner within said non-porous rim and said porous metal shell.

7. The orthopedic prosthesis of claim 6 wherein said annular ring is inboard of said diametrically opposed raised walls.

8. An orthopedic prosthesis for implantation into a bone of a patient, said orthopedic prosthesis comprising a hemispherical body that includes an open end defining a perimeter, said orthopedic prosthesis further comprising:

a porous metal shell adapted to be affixed within the bone, said porous metal shell defining continuous porous metal from an inner bearing engaging surface to an outer bone engaging surface, said outer bone engaging surface adapted to receive bone ingrowth after the implantation;

a non-porous rim defined at a radial edge of said porous metal shell and being metallurgically bonded to said porous metal shell by an application of high pressure that results in a bond between said non-porous rim and said porous metal shell such that said non-porous rim is non-removable from said porous metal shell; and

a bearing liner separately formed from and insertable through said non-porous rim to a position against said inner bearing engaging surface of said porous metal shell;

wherein said non-porous rim comprises;

an interlocking structure defined by respective radially overlapping portions of porous metal shell and non-porous rim;

at least one pair of raised walls extending proud from a planar surface defined on an outer face of said non-porous rim, wherein each raised wall of said at least one pair of raised walls defines a retaining feature formed thereon;

wherein said interlocking structure is formed entirely around said perimeter of the orthopedic prosthesis and defines a first annular collar that projects radially outwardly from said non-porous rim and a first annular pocket formed in said porous metal shell, wherein said first annular collar nests within said first annular pocket, and

wherein said interlocking structure further defines a second annular collar that projects radially inwardly from said porous metal shell and a second annular pocket formed in said non-porous rim, wherein said second annular collar nests within said second annular rim.

9. The orthopedic prosthesis of claim 8 wherein said at least one pair of raised walls extend to a position laterally offset from said planar surface.

10. The orthopedic prosthesis of claim 8 wherein each of said retaining features are positioned outboard of an outermost surface of said inner bearing engaging surface.

11. The orthopedic prosthesis of claim 8 wherein each of said retaining features comprise a tapered inner wall surface that slopes radially inwardly from said outer face of said non-porous rim.

12. The orthopedic prosthesis of claim 11 wherein each of said retaining features comprises two diametrically opposed retaining features.

13. The orthopedic prosthesis of claim 8, further comprising:

an annular ring selectively located within an annular groove formed on an

inner surface of the non-porous rim, said annular ring capturing said bearing liner within said non-porous rim and said porous metal shell.

14. The orthopedic prosthesis of claim 13 wherein said annular ring is inboard of said diametrically opposed raised walls in an installed position.

15. An orthopedic prosthesis for implantation into a bone of a patient, said orthopedic prosthesis comprising a hemispherical body that includes an open end defining a perimeter, said orthopedic prosthesis further comprising:

a porous metal shell adapted to be affixed within the bone, said porous metal shell defining continuous porous metal from an inner bearing engaging surface to an outer bone engaging surface, said outer bearing engaging surface adapted to receive bone ingrowth after the implantation, said porous metal shell defining a first annular pocket formed thereon and a first annular collar that projects radially inwardly therefrom;

a non-porous rim defined at a radial edge of said porous metal shell and being metallurgically bonded to said porous metal shell such that said non-porous rim is non-removable from said porous metal shell, said non-porous rim defining a second annular pocket formed thereon and a second annular collar that projects radially outwardly therefrom, wherein each of said first and second annular collars nest within each of said first and second annular pockets, respectively, creating an overhanging interlock between said porous metal shell and said non-porous rim entirely around said perimeter, said non-porous rim further comprising at least one pair of raised walls extending proud and raised above a planar surface defined on an outer face of said non-porous rim, wherein each raised wall of said at least one pair of raised walls defines a retaining feature formed at least in part by a wall surface tapering generally inwardly from said outer face of said non-porous rim; and

a bearing liner separately formed from and insertable through said non-porous rim to a position against said inner bearing engaging surface of said porous metal shell.

16. The orthopedic prosthesis of claim 15 wherein said non-porous rim is formed entirely around said perimeter of the orthopedic prosthesis.

17. The orthopedic prosthesis of claim 15 wherein said porous metal shell defines a porosity gradient from said outer bone engaging surface to said inner bearing engaging surface and includes a combination of metal and pores having a ratio of between about 3:

1 and about 8;

1, respectively.