[Pathohistology of femoral head necrosis]

Necrosis of the femoral head represents a special form of aseptic bone necrosis because it develops in the high load-bearing region of the hip joint. The incidence of the disease is not precisely known. Characteristic macroscopic findings include articular cartilage detachment in the load-bearing zone immediately below the subchondral osseous lamella, the bordering necrosis of the marrow space and bone cells, incursion of the spongiosa, and the gradual loss of roundness of the femoral head. The cause of the disease is a disorder in circulation supplying the proximal femur. The disease frequently occurs in disorders of lipometabolism, after steroid medication, in sickle cell anemia and chronic alcoholism, and after fractures of the femoral neck. Histopathological classification should distinguish between arthropathy with secondary femoral head necrosis and primary forms. Differential diagnosis based on histological findings should distinguish between primary coxarthrosis with secondary femoral head necrosis, metastases, and a few bone tumors in the epiphyses. Clear cell chondrosarcoma is particularly important in the context.