[Animal experiment studies of callus formation by hydroxyapatite injection].

Hydroxy-apatite may be suspended well in liquid high-molecular gelatine. This renders possible an application by local injection. By means of experimental animal investigations in 64 rabbits it could be proved, that hydroxy-apatite stimulates osteogenesis and local callus formation when being injected at artificial bone defects. Gelatine on its own without any HA-grains only leads to a callus-free bridging of the bone defect. In case of an injection of the HA-suspensions to muscular soft tissue, no stimulation of the osteogenesis could be proved. It has to be concluded, that hydroxy-apatite stimulates osteogenesis. To achieve this effect, a direct contact to osteogenetic cells is necessary.