Abstract: | A graft of periosteum from the tibia of 27 rabbits was incubated in vitro with tritiated thymidine for 24 hours and then transplanted into a full-thickness defect in the patellar groove. The rabbits were managed after the operation on continuous passive motion (CPM), and the joints excised at intervals of two to 21 days. After one week the cells had begun to synthesize glycosaminoglycan and by two weeks the tissue resembled immature hyaline cartilage. Thymidine-labeled cells were seen throughout the entire regenerated tissue. The cellular origin of the hyaline-like tissue that filled the defects was the progenitor cells of the periosteal graft. |