[A new resorbable bone-cartilage replacement transplant. Results of an animal experiment study]

Hyaline cartilage is thought to be unable to regenerate. All efforts so far--including autologous chondrocyte cell transplantation--to reconstruct cartilage defects in joints have not been totally convincing. However, mesenchymal cells are able to differentiate into chondrocytes under mechanical pressure conditions. In this study, an open porous resorbable two-layer "bioimplant" was constructed in which mechanical pressure was exerted onto mesenchymal cells when migrated into the open porous structure of the bioimplant. Differentiation of the cells into chondrocytes was thus induced. The bioimplants were implanted into the medial condyles of nine rabbits and left in place for eight or twelve weeks, respectively. In seven of these cases, cartilage formation was found, in contrary to the controls in which only connective tissue and bone had grown into the empty holes. The new bioimplants have proven their effectiveness in cartilage defect repair and might evolve in the future as a new alternative treatment of full thickness defects of joint surfaces.