Osteoinductive activity of composites of bone morphogenetic protein and pure titanium.

Titanium sponges were infused with bone morphogenetic protein (BMP-Ti), and the osteoinductivity of the resultant composite was measured. New bone formation occurred three weeks after implantation and was identified by soft x-ray analysis. Quantitative analysis showed no significant difference between BMP-Ti composites and control samples (BMP only). Consequently, pure titanium neither inhibited nor promoted BMP activity. Chondrocytes and new bone formation occurred in direct contact with the surfaces of the titanium. X-ray microanalysis demonstrated new bone formation inside the pores of the titanium sponges. The BMP-Ti composite has interesting properties as an osteoinductive implant and has potential practical clinical applications.