SBIR-STTR Award

Press-fit and porous coated joint replacement implants often fail due to formation of a fibrous capsule causing loosening and pain, eventually requiring revision. Early in vitro and in vivo experiments suggest that surface microgeometry significantly modulates rate and direction of growth of connective tissue cell colonies. These in vitro effects on colony formation kinetics and cell function of rat tendon fibroblast and rat bone marrow cells are being quantified. Cells are cultured on a selected range of surface microgeometrics constructed from titanium-coated templates. A cell colony formation model permits accurate analysis of these effects.The potential commercial application as described by the awardee: The enhanced design of bone attachment surfaces forjoint implants will provide an improved marketable product. Over 400,000 total hip arthroplasties are performed annually worldwide. The field of orthopaedic joint implants is currently projected to grow at 20 percent per year over the next ten years. As these devices are used in younger, more active individuals, improved non-cemented surfaces will be needed in an ever-increasing proportion.

The goal of this research is to design micromachined patterned surfaces for orthopaedic implant devices that selectively cause the following types of reactions: 1) promote bone and restrict soft tissue ingrowth in critical regions; 2) enhance soft tissue growth while inhibiting bone growth; and 3) act as a barrier for soft tissue ingrowth into bone attachment areas. Combinations of the microgeometries will be tested for their ability to encourage and/or discourage site-specific tissue ingrowth and thus achieve a longer-lived hip arthroplasty device. The enhanced design of bone attachment surfaces for joint implant devices will provide an improved marketable product. The field of orthopaedic joint implants is projected to grow at 20% per year over the next 10 years with currently over 400,000 total hip arthroplasties performed annually