Orthopedic implant system

• US 6,312,473 B1
• Filed: 10/20/1999
• Issued: 11/06/2001
• Est. Priority Date: 07/11/1996
• Status: Expired due to Fees

• Current Assignee: Yoshiki Oshida
• Original Assignee: Yoshiki Oshida
• Inventors: Oshida, Yoshiki
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US09/421,390
• Time in Patent Office: 748 Days
• Field of Search: 623/11.11, 623/16.11, 623/23.15, 623/23.26, 623/23.29, 623/23.3, 623/23.36, 623/23.37, 623/23.58, 623/23.59, 623/23.6, 623/23.61, 623/23.62, 623/23.63, 623/23.55, 623/23.53, 623/22.53, 623/22.39
• US Class Current: 623/23.55
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• 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 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30967 Diffusion bonding
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3631 with an integral complete or partial peripheral collar or bearing shoulder at its base
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2310/00407 Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00952 Coating, pre-coating or prosthesis-covering structure made of bone cement, e.g. pre-applied PMMA cement mantle
• CPC Class Codes: A61L 24/0089 containing inorganic fillers not covered by groups A61L24/0078 or A61L24/0084
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate

Abstract

It is an object of the present invention to provide an improved orthopedic implant system with satisfied biological, mechanical and morphological compatibilities.

Solid metal femoral stem and solid metal acetabular head are covered with diffusion-bonded foamed-shaped sheet made of commercially pure titanium or titanium alloy(s). The open-cells in said foamed metal sheet are impregnated with biocompatible polymethyl methacrylate resin cement, which is reinforced with selected oxides including alumina, magnesia, zirconia, or a combination of these oxides along with an application of a small amount of a metal primer agent.

Claims

1. An orthopedic implant system comprising an acetabular cup with an insert portion, a femoral stem with a ball head, and a reinforced bone cement comprising polymethyl methacrylate resin reinforced with metallic oxide particles, wherein at least a portion of an outer peripheral surface of said acetabular cup and at least a portion of an outer surface of said femoral stem are covered with a metallic foam-shaped network sheet which is at least partially impregnated with said reinforced bone cement.

2. The orthopedic implant system as claimed in claim 1, wherein said metallic foam-shaped network sheet is made of commercially pure titanium or a titanium-based alloy.

3. The orthopedic implant system as claimed in claim 1 or 2, wherein an average open-cell size of the metallic foam-shaped network is 1 mm, and an average thickness of said metallic foam-shaped network sheet is 3 mm.

4. The orthopedic implant system as claimed in claim 1 or 2, wherein said metallic foam-shaped network sheet is partially or entirely bonded onto said acetabular cup and said femoral stem through diffusion bonding.

5. The orthopedic implant system as claimed in claim 1 wherein said metallic oxide particles are selected from the group consisting of aluminum oxide, magnesium oxide, zirconium oxide, and mixtures thereof.

6. The orthopedic implant system as claimed in claim 1, wherein said metallic foam-shaped network sheet has a reticulated open cell geometry of duodecahedronal cell shapes.