Histological and biochemical evaluation of osteogenic response in porous hydroxyapatite coated alumina ceramics

We compared the osteogenic response in porous alumina (Al) and hydroxyapatite coated porous alumina ceramic (HA/Al) by grafting rat bone marrow cells with these implants subcutaneously in the back of syngeneic rats. The ceramics did not show any bone formation without marrow, but did when combined with marrow cells. The osteogenesis in HA/Al began directly on the ceramic surface, but in AI began away from the ceramic surface, and fibrous tissue interposition was seen between the de novo bone and its surface. Alkaline phosphatase activity and bone specific bone gla protein content in HA/Al with marrow were both about three times higher than in AI with marrow. These results indicate that HA/Al has excellent osteoconductive properties and that a composite of marrow and HA/Al is a clinically applicable osteogenic biomaterial.