Fresh immature articular cartilage allografts. A study on the integration of chondral and osteochondral grafts both in normal and in papain-treated knee joints of rabbits.

The integration of immature cartilage allografts to knee joints of both normal rabbits and those submitted to arthritis through papain was studied for a period of up to 9 months. Two types of grafts were compared: chondral--constituted only by cartilage, and osteochondral--cartilage plus a thin layer of subchondral bone. The integration of the grafts was analyzed through inspection of the articular surface and histologic sections. The viability of the grafts was checked through the incorporation of 35SO4 on the chondral matrix. The following conclusions were drawn: (1) A large member of the grafted cartilages were well accepted without histological evidence of immunological rejection, and metabolically active 9 months after transplantation. (2) The chondral graft was found to be superior to the osteochondral one regarding the integration, but both showed tendency to degeneration with time. (3) The presence of arthritis previously induced by papain affected the integration of the grafts causing a higher precentage of degeneration on the grafts causing a higher precentage of degeneration on the grafted cartilage.