Healing of osteochondral grafts. An animal study

Aim: Autologous grafting has developed into one of the preferred methods of treatment for focal osteochondral lesions, although basic research on this topic remains sparse. In an animal study, questions regarding the healing of such osteochondral transplants are clarified. Method. An autologous oste ochondral transplantation was performed on the ovine knee using the standar d operative protocol. Two groups, consisting of 10 sheep each, were evaluat ed after 3 and 6 months, respectively. Results. During the clinical evaluat ion of the, specimens, neither osteophytes nor synovial changes were observ ed. The consistency of the cartilaginous tissue began to reach a level equi valent to the surrounding tissue only after 6 months. Macroscopically, the superficial border of the transplanted osteochondral plug could easily be o utlined at both time points. Radiographically, a solid osteointegration of the graft could already be documented at 3 months. In contrast, integration of the chondral surface of the OAT was not seen macro- or microscopically at any point in time. A firm physical interdigitation of the reconstructed joint surface could not be demonstrated. Conclusions. The lack of integrati on of the cartilaginous portion of the transplanted plugs into the reconstr ucted joint surface leads to questions regarding the long-term survival of the joint itself.