The biologic value of cryo-preserved homologous spongiosa for filling up subchondral bone defects shall be investigated. The experimentations are made on rabbits. Three groups are built in order to evaluate the results: Group I: No filling up of defects. Group II: Lining with fresh autologous spongiosa. Group III: Lining with cryo-preserved homologous spongiosa. The lining is performed after standardized subchondral setting of defects in the zone of maximal load of the medial femur condyle. As well in non-filled up defects as after lining with homologous spongiosa, macroscopic and microscopic examinations show between the fourth and eighth postoperative week a hernia of the cartilage-bone lamella. The autologous spongiosa, however, guarantees the stability and vitality of the joint cartilage, as is shown by the results found twelve weeks after the operation. The results may be explained by the retarded osteogenetic power and the long period of catabolism of the homologous spongiosa.
