Acetabular shell with screw access channels

• US 6,709,462 B2
• Filed: 01/11/2002
• Issued: 03/23/2004
• Est. Priority Date: 01/11/2002
• Status: Active Grant

• Current Assignee: Mayo Foundation For Medical Education And Research (Mayo Clinic)
• Original Assignee: Mayo Foundation For Medical Education And Research (Mayo Clinic)
• Inventors: Hanssen, Arlen D.
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US10/044,044
• Publication Number:
  US 20030135281A1
• Time in Patent Office: 802 Days
• Field of Search: 623/22.21, 623/22.32, 623/22.33, 623/22.34, 623/22.35, 623/22.36, 623/22.37, 623/20.34, 623/23.5
• US Class Current: 623/22.35
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/4609 of acetabular cups
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30561 breakable or frangible
• CPC Class Codes: A61F 2002/30682 Means for preventing migration of particles released by the joint, e.g. wear debris or cement particles
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30805 Recesses of comparatively large area with respect to their low depth
• CPC Class Codes: A61F 2002/3081 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30813 Stepped or enlarged blind bores, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30827 Plurality of grooves
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/3401 with radial apertures, e.g. radial bores for receiving fixation screws
• CPC Class Codes: A61F 2002/3403 Polar aperture
• CPC Class Codes: A61F 2250/0024 : made from both porous and non-porous parts, e.g. adjacent parts
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• 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 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF

Abstract

An outer shell for a socket of a joint prosthesis is disclosed. The outer shell includes an outer wall defining an outer surface of the shell and an inner wall defining an inner surface of the shell. The outer wall has pores to permit bone tissue to grow into the outer wall, and the inner surface of the shell engages the socket. The inner wall has access channels suitable for seating a bone screw. The access channels are closed off by an associated integral section of the shell. Preferably, each access channel is closed off by a section of the outer wall so that the shell retains maximal outer surface area for bone tissue ingrowth. When a number of bone screws are needed for affixation of the shell to bone, a number of locations for bone screws can be created in the shell by opening the closed access channels.

Claims

1. An outer shell for a socket of a joint prosthesis, the outer shell comprising:

an outer wall having pores of a size sufficient to permit bone tissue to grow into the outer wall, the outer wall defining an outer surface of the outer shell; and

an inner wall defining an inner surface of the outer shell, the inner surface of the outer shell suitable for engaging an outer surface of the socket, the inner wall having at least one access channel extending through the inner wall, each access channel being suitable for seating a bone screw,

wherein at least one access channel that extends through the inner wall is closed off by an associated integral section of the outer wall so as to not extend through the outer surface of the outer shell.

2. The outer shell of claim 1 wherein:

the inner wall is joined to the outer wall such that a boundary is formed between the inner wall and the outer wall, and

at least one associated integral section of the outer wall consists of a section of the outer wall extending from the boundary to the outer surface of the outer shell.

3. The outer shell of claim 1 wherein:

the inner wall is joined to the outer wall such that a boundary is formed between the inner wall and the outer wall, and

at least one associated integral section of the outer wall consists of a section of the outer wall extending from the outer surface of the outer shell to a position between the outer surface and the boundary.

4. The outer shell of claim 1 wherein:

at least one of the access channels extends from the inner surface of the outer shell to the outer surface of the outer shell.

5. The outer shell of claim 1 wherein:

the inner wall has a plurality of access channels extending through the inner wall, and

a plurality of access channels that extend through the inner wall are closed off by an associated integral section of the outer wall so as to not extend through the outer surface of the outer shell.

6. The outer shell of claim 1 wherein:

each associated integral section is suitable for penetration with a self tapping bone screw or a drill bit.

7. The outer shell of claim 1 wherein:

the outer wall comprises interconnected metallic particles that define the pores, the metallic particles comprising titanium, titanium alloys, cobalt alloys, stainless steel alloys, tantalum alloys, or mixtures thereof.

8. The outer shell of claim 1 wherein:

the inner wall comprises titanium, titanium alloys, cobalt alloys, stainless steel alloys, tantalum alloys, or mixtures thereof.

9. The outer shell of claim 1 wherein:

the outer wall consists of an integral unitary structure.

10. The outer shell of claim 1 wherein:

the outer surface of the outer shell has a plurality of depressions.

11. The outer shell of claim 1 wherein:

the outer surface of the outer shell has a coating of a bone ingrowth promoting material.

12. The outer shell of claim 11 wherein:

the bone ingrowth promoting material is selected from hydroxyapatite, calcium phosphates, growth factors, bone morphogenic proteins, and mixtures thereof.

13. An outer shell for a socket of a joint prosthesis, the outer shell comprising:

an outer wall having pores of a size sufficient to permit bone tissue to grow into the outer wall, the outer wall defining an outer surface of the outer shell; and

an inner wall defining an inner surface of the outer shell, the inner surface of the outer shell suitable for engaging an outer surface of the socket, the inner wall having a plurality of access channels suitable for seating a bone screw,

wherein at least one access channel is closed off by an associated integral section of the outer shell so as to not extend through the outer surface of the outer shell,

wherein the associated integral section includes a section of the inner wall and a section of the outer wall, and

wherein at least one of the access channels extends completely through the inner wall and the outer wall.

14. The outer shell of claim 13 wherein:

each associated integral section is suitable for penetration with a self tapping bone screw or a drill bit.

15. The outer shell of claim 13 wherein:

the outer wall comprises interconnected metallic particles that define the pores, the metallic particles comprising titanium, titanium alloys, cobalt alloys, stainless steel alloys, tantalum alloys, or mixtures thereof.

16. The outer shell of claim 13 wherein:

the inner wall comprises titanium, titanium alloys, cobalt alloys, stainless steel alloys, tantalum alloys, or mixtures thereof.

17. The outer shell of claim 13 wherein:

the outer wall consists of an integral unitary structure.

18. The outer shell of claim 13 wherein:

the outer surface of the outer shell has a plurality of depressions.

19. The outer shell of claim 13 wherein:

the outer surface of the outer shell has a coating of a bone ingrowth promoting material.

20. The outer shell of claim 19 wherein:

the bone ingrowth promoting material is selected from hydroxyapatite, calcium phosphates, growth factors, bone morphogenic proteins, and mixtures thereof.