Hydrogel arthroplasty device

• US 9,387,082 B2
• Filed: 02/24/2014
• Issued: 07/12/2016
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: US Department of Veterans Affairs (Government of the United States of America), Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: US Department of Veterans Affairs (Government of the United States of America), Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Myung, David, Kourtis, Lampros, Hartmann, Laura, Frank, Curtis W., Goodman, Stuart B., Carter, Dennis R.
• Primary Examiner(s): Salvitti, Michael A
• Application Number:
  US14/188,257
• Publication Number:
  US 20140172098A1
• Time in Patent Office: 869 Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3603 implanted without ablation of the whole natural femoral head endoprosthetic cartilage A61F2/30756
• CPC Class Codes: A61F 2/3872 Meniscus for implantation between the natural bone surfaces
• CPC Class Codes: A61F 2/4202 for ankles
• CPC Class Codes: A61F 2/4225 for feet, e.g. toes
• CPC Class Codes: A61F 2/4241 for hands, e.g. fingers
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30754 Implants for interposition between two natural articular surfaces
• CPC Class Codes: A61F 2210/0061 swellable
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61L 2430/24 for joint reconstruction
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/3843 Connective tissue
• CPC Class Codes: A61L 27/50 : Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 27/52 : Hydrogels or hydrocolloids

Abstract

An arthroplasty device is provided having an interpenetrating polymer network (IPN) hydrogel that is strain-hardened by swelling and adapted to be held in place in a joint by conforming to a bone geometry. The strain-hardened IPN hydrogel is based on two different networks: (1) a non-silicone network of preformed hydrophilic non-ionic telechelic macromonomers chemically cross-linked by polymerization of its end-groups, and (2) a non-silicone network of ionizable monomers. The second network was polymerized and chemically cross-linked in the presence of the first network and has formed physical cross-links with the first network. Within the IPN, the degree of chemical cross-linking in the second network is less than in the first network. An aqueous salt solution (neutral pH) is used to ionize and swell the second network. The swelling of the second network is constrained by the first network resulting in an increase in effective physical cross-links within the IPN.

Claims

1. A cartilage replacement prosthesis having a first surface and a lubricious second surface, the prosthesis comprising a covalently cross-linked polyacrylic acid network and a polyurethane network, the polyacrylic acid network forming a composition gradient within the polyurethane network such that the polyacrylic acid content of the prosthesis is at a maximum at the second surface and decreases with distance from the second surface towards the first surface, the prosthesis comprising polyurethane at all distances from the second surface to the first surface, the prosthesis comprising water, wherein the water forms a continuous hydration gradient within the polyacrylic acid network and the polyurethane network.

2. The prosthesis of claim 1 wherein the polyacrylic acid content at the first surface is zero.

3. The prosthesis of claim 1 wherein the first surface has a primarily concave shape and the second surface has a primarily convex shape.

4. The prosthesis of claim 3, wherein the primarily concave shape of the first surface is adapted to mate with a femoral head.

5. The prosthesis of claim 1 wherein the first surface has a primarily convex shape and the second surface has a primarily concave shape.

6. The prosthesis of claim 5, wherein the primarily convex shape of the first surface is adapted to mate with an acetabular cavity.

7. The prosthesis of claim 1 further comprising a bonding agent on the first surface of the prosthesis adapted to attach the prosthesis to a bone.

8. The prosthesis of claim 1 wherein the first surface is adapted for anchoring the prosthesis to bone.

9. The prosthesis of claim 1 wherein the second surface is adapted to articulate with another surface different from the first surface.