The causes of femoral head necrosis include alcoholism, after hormone therapy, after local radiation therapy, decompression sickness, systemic lupus erythematosus, coagulation dysfunction, hemoglobinopathy, and trauma, etc. Alcoholism and hormonal femoral head necrosis are the most common in China. Various causes of impaired blood circulation to the femoral head can lead to ischemia and necrosis of the femoral head and the consequent bone tissue repair response, which in turn leads to femoral head collapse and degenerative changes of the hip joint. Ischemia, necrosis, collapse and osteophytes are the different pathological stages of femoral head necrosis. Ischemia is reversible, while necrosis, collapse and osteophytes, are irreversible pathological changes.