Implanting hydroxyapatite-coated porous titanium with bone morphogenetic protein-2 and hyaluronic acid into distal femoral metaphysis of rabbits

Objective: To assess the osseointegration capability of hydroxyapatite-coated porous titanium with bone morphogenetic protein-2 (BMP-2) and hyaluronic acid to repair defects in the distal femur metaphysis in rabbits. Methods: Porous titanium implants were made by sintering titanium powder at high temperature, which were coated with hydroxyapatite by alkali and heat treatment and with BMP-2 combined with bone regeneration materials. And hyaluronic acid was further used as delivery system to prolong the effect of BMP-2. The implants were inserted into the metaphysis of the distal femur of rabbits. The animals were killed at 6, 12 and 24 weeks to accomplish histological and biomechanical analyses. Results: According to the result of histological analysis, the osseointegration in BMP-2 group was better than that of the HA-coated porous titanium group. In push-out test, all the samples had bigger shear stress as time passed by. There was statistical difference between the two groups in 6 and 12 weeks but not in 24 weeks. Conclusion: Hydroxyapatite-coated porous titanium with BMP-2 and hyaluronic acid has a good effect in repairing defects of distal fumur in rabbits, which is a fine biotechnology for future clinical application.