Chondrolysis in rats with vascular deprivation - Induced oisteonecrosis of the femoral neck

This report describes an animal model of chondrolysis, i.e., acute necrosis of the articular cartilage. The blood circulation of rats' femoral heads was disrupted by incising the periosteum at the base of the femoral neck and cutting the ligamentum teres. The joint cartilage was necrotic in 18 of the 30 and 21 of the 39 osteonecrotic femoral heads of rats killed on the 30th and 42nd postoperative day, respectively. Chondrolysis was limited to the superficial cartilage layer in mild cases. It involved the entire cartilage in the more severely affected instances. Chondroclasts abutted on the necrotic cartilage where fibrous tissue replaced the subchondral bone plate. At the most advanced stage, the cartilage was segmentally absent, polished bone constituting the articular aspect. Chondrolysis, rarely detected in otherwise healthy children, commonly occurs in patients with a slipped capital femoral epiphysis, a disorder commonly associated with osteonecrosis of the femoral head. The herein presented model may serve the study of necrosis of the cartilaginous and osseous compartments of the femoral head in a small laboratory animal.