The articular tissue generated on carbon fiber rods in rabbit knee joints after 75 days of intermittent active motion was compared with tissue generated on carbon fiber rods whose articular surfaces were covered with a free reversed periosteal graft. Both methods were effective in generating articular tissue; however, tissue with ultrastructural characteristics similar to those of hyaline cartilage was noted more frequently on the composite implants. If such composite implants were clinically effective then they might be useful in treating symptomatic osteochondral defects.