Surface Modification to Improve Osseous Integration

We will improve the fixation of non-cemented titanium hip prostheses by coating the porous surfacescollagens and growth factors. Two collagens (types I and IV) will be covalently coupled to the implapatented BSI photochemistry, and two growth factors will be non- covalently incorporated into each cmanner that slowly releases the GF's over several days. The collagen/GF coatings are expected to imposteoblasts into the porous surface of the implants, thus, 1) reducing the time required for implantextent of bone ingrowth into the porous region, and 3) increasing the effective life of the implantloosening. During the Phase I in vitro studies, each collagen type will be photoimmobilized onto CPporous CP titanium disks, with tritium-labelled collagens being used to quantitate loading levels. Eincorporated into each collagen coating and the combinations will be evaluated for osteoblast attachexpression of differentiated characteristics. Finally, coatings that demonstrate superior in vitro papplied to porous- surface titanium implants, 2) implanted in a rabbit metaphyseal model, and 3) evastrength of bonding to bone and histologically for inflammation and tissue ingrowth.