Autogenous transplantation of apophyseal cartilage to osteochondral defects of joints.

35S was administered to 20 puppies which had been exposed to transplantation of osteochondral apophyseal transplants from the iliac crest to defects of the femoral condyles. Some transplants were implanted into defects within the joint surfaces whereas others were implanted outside the joint surfaces. An autoradiographic study was performed to assess the functional vitality of the transplanted cartilage at varying intervals up to 14 months. This study further necessitated an investigation of the normal pattern of incorporation of 35S in the iliac crest. The studies revealed that the incorporation of 35S within the apophysis of the iliac crest was similar to that seen within pressure epiphyses, being heaviest in the proliferating and hypertrophying cells in the growth plate and around the secondary centre of ossification. The increased turnover of sulphur around the secondary centre of ossification declined, however, when the initial stage of the ossification was passed and when hypertrophy of cartilage cells was no longer seen. Ossification then took place without intensified production of organic sulphur-containing compounds in this region. The study further showed that apophyseal cartilage was still able to incorporate 35S following transplantation to the mentioned defects, except in some basal central areas adjacent to the metaphyseal bone. These findings suggested that the cartilage not only survived, but also preserved its capacity for synthetizing sulphur-containing compounds, probably chondroitin sulphate.