Cartilage destruction in experimentally induced osteoarthritis.

Section of the anterior cruciate ligament in the knee joint of mature dogs resulted in a progressive fibrillation of both tibial and femoral condylar cartilages. Reduced tissue microhardness and increased water content preceded fibrillation while fixed charge density remained unchanged. A different histological pattern of initial fibrillation was found, however, in femoral and tibial cartilages which exhibited tangential cleft and vertical splits, respectively. Tangential fibrillation alone was associated with necrosis of superficial cells. This suggests that the mechanism of early osteoarthritic cartilage destruction varies in different articular surfaces.