Destruction of joint homografts. An experimental study.

The host synovium undergoes a striking transformation at about 26 weeks after joint homografting. Histologically the synovium invaded and destroyed the graft with which it came in contact, becoming markedly hypercellular; the infiltrate consisted mainly of plasma cells and lymphocytes. The synovium at this stage closely resembled a rheumatoid pannus. The cartilage in contact with this invasive synovium lost its staining qualities, failed to take up S-35, and was gradually destroyed. The mechanism causing this transformation remains unclear. It is postulated that these changes could be due to an inflammatory or immune response.