Kubota W
Department of Orthopedic Surgery, Yokohama City University School of Medicine, Kanagawa, Japan.
Nihon Seikeigeka Gakkai Zasshi. 1992 Jan;66(1):110-9.
Hydroxyapatite thermal decomposition product is a mixture of alpha-tricalcium phosphate and tetracalcium phosphate. It is hardened by mixing with water in vitro. This decomposition product was mixed with water solution (HAp cement) and was injected into the femora of twenty-eight rabbits. The injected decomposition product was found to be solid at the time of sacrifice in all animals. No radiolucent zones surrounding the surface of HAp cement were seen two, four, nine and twelve weeks after injection. Histological examination revealed the new bone formation in direct contact with the surface of HAp cement more than two weeks after injection. Histomorphometrical measurements showed an enlargement of the new bone area at the circumference of injected HAp cement block with passage of the time. New bone formation was found to be larger in the metaphysis of the femur than in the diaphysis. HAp cement apparently has a good affinity to bone and is expected to be successfully applied clinically as bioactive bone cement.