Reconstruction of patellar cartilage defects with free periosteal grafts. An experimental study.

The osteo-chondrogenic potential of free periosteal grafts was investigated within the knee joint in 26 rabbits aged four to six weeks. A total of 36 knee joints were operated on. The grafts were stripped from the medial side of the right tibia and sutured on the articular surface of the patella, from which the cartilage had been totally excised to the subchondral bone. In 16 knees the graft was sutured with the cambium layer towards the subchondral bone and in eight knees the fibrous layer faced the bone. In the control group of twelve knees the patellar articular cartilages were excised and no periosteal transplant was grafted to the patellar articular surface. In the transplantation group cartilage formation could be seen already one week after the operation. There were no marked differences between the series with the cambium layer facing the subchondral bone or the group with the fibrous layer facing the bone. At 20 weeks the hypertrophied cartilage had thinned and resembled normal joint cartilage. In the control group the histological picture resembled osteoarthritis.