Canine acetabular cup

• US 7,169,185 B2
• Filed: 05/26/2004
• Issued: 01/30/2007
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: BioMedtrix, LLC
• Original Assignee: Impact Science and Technology Incorporated
• Inventors: Sidebotham, Christopher G.
• Primary Examiner(s): Stewart; Alvin J.
• Application Number:
  US10/853,970
• Publication Number:
  US 20050267585A1
• Time in Patent Office: 979 Days
• Field of Search: 623/22.21, 623/22.28, 623 2215- 222, 623/22.23, 623 2224- 2227, 623 2231- 2233, 623/22.42
• US Class Current: 623/22.21
• CPC Class Codes: A61B 17/1666 for the acetabulum
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30355 Cylinder of elliptical or oval basis
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30487 Circumferential cooperating grooves and beads on cooperating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/307 Prostheses for animals
• CPC Class Codes: A61F 2002/30769 madreporic
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3414 Polar protrusion, e.g. for centering two concentric shells
• CPC Class Codes: A61F 2002/342 the outer shell having circumferential protrusions parallel to the equatorial plane, e.g. circumferential fins or wings
• CPC Class Codes: A61F 2002/349 Shell having a wavy or undulated peripheral rim
• 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 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 2310/00407 Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61L 27/04 Metals or alloys
• CPC Class Codes: A61L 27/10 : Ceramics or glasses
• CPC Class Codes: A61L 27/306 : Other specific inorganic materials not covered by A61L27/303 - A61L27/32

Abstract

A plurality of canine acetabular cups designed to fit within different sized spherical reamed bone cavities to produce controlled interference without use of cements, screws or nails. Each of the canine acetabular cups, regardless of size, mates with a common femoral head, providing interchangeability. The controlled interference is obtained through use of a multiple curvature Ti—Al—V shell having a porous coating. The interference starts from zero at 50 degrees from the apex of the shell and extends to full interference value at 90 degrees from the apex. The Ti—Al—V shell carries a UHMW polyethylene insert, which is locked by interference, a non-circular post mated with an elongated opening and a circumferential locking groove mated with an interior projection. Initial stability is provided immediately after surgery due to the interference arrangement; long term stability is afforded by bone ingrowth.

Claims

1. A canine acetabular cup system, comprising:

a. a plurality of different sized acetabular cups for selection by a surgeon, said acetabular cups being adapted for use with a common-sized femoral head;

b. each said acetabular cups being provided with a truncated cutout on one side thereof for improved abduction and canine hip movement;

c. said acetabular cup adapted to be held in place within a reamed spherical bone cavity by controlled interference between a multiple curvature Titanium-Aluminum-Vanadium shell of said acetabular cup and the bone cavity, providing for frictional attachment of the canine acetabular cup and imparting initial stability to the implant immediately after surgery;

d. said shell having a porous coating of chemically pure Titanium beads sintered between circumferential rings on the outer surface of said shell, to increase friction at contact surfaces with the reamed bone cavity, promote bone growth and provide for long term stability of the implant;

e. said shell having an ultra high molecular weight polyethylene insert attached within the shell by an interference fit, having locking features that prevent rotational, horizontal and vertical displacements of the said polyethylene insert with respect to the said shell;

f. said locking feature comprising a non-cylindrical opening at an apex of said shell to receive and mate with a corresponding non-circular post at the apex of said polyethylene insert thereby preventing relative rotation of said polyethylene insert with respect to said shell;

g. said locking feature comprising a groove in said polyethylene insert that mates with a corresponding interior projection of said shell, thereby preventing horizontal and vertical movement;

h. said polyethylene insert having a spherical opening to receive said common-sized femoral head; and

i. said polyethylene insert having a lip covering the basal surface of said shell, preventing contact between said common-sized femoral head and said shell.

2. A canine acetabular cup system as recited by claim 1, wherein said plurality of multi-sized acetabular cups have nominal diameters adapted to produce an interference fit with different-sized spherical reamed bone cavities, the diameters of said acetabular cups being approximately 24, 26, 28, 30 and 32 mm.

3. A canine acetabular cup system as recited by claim 1, wherein said truncated cut out is at an angle of 45 degrees from the basal plane and is off set from the center of said shell member.

4. A canine acetabular cup system as recited by claim 1, wherein said controlled interference is provided by gradually increased interference between said shell and the spherically reamed bone cavity, said interference being extant at angular locations about 50°

to 90°

from said apex.

5. A canine acetabular cup system as recited by claim 1, wherein said porous coating of 250 ±

50 μ

m (0.01 ±

0.0025 inches) beads of chemically pure Titanium beads has a thickness of 0.8 mm (0.030 inches).

6. A canine acetabular cup system as recited by claim 1, wherein said cylindrical opening at the apex of said shell has a dimension of 6 by 3.8 mm (0.240 inches by 0.152 inches).

7. A canine acetabular cup system as recited by claim 1, wherein said polyethylene insert has a thickness ranging from 2.4 mm to 6.4 mm (0.1 to 0.2 inches) based on the size of the acetabular cup.

8. A canine acetabular cup system as recited by claim 1, wherein said common size femoral head has a diameter of 17 mm.