Femoral head necrosis, known as ischemic necrosis of the femoral head, or aseptic necrosis of the femoral head, is a lesion caused by localized poor blood flow to the femoral head for a variety of reasons, which leads to further ischemia of bone cells, necrosis, fracture of bone trabeculae, and collapse of the femoral head. The clinical manifestations are hip pain, joint movement and walking dysfunction. Common causes include application of hormones, alcohol abuse, trauma, and history of related diseases. Depending on the severity of the disease, it is divided into stages 0 to 4. The femoral head may gradually collapse and flatten, joint space narrowing, bone redundancy formation, shortening of the lower limbs, subluxation and dislocation, which can lead to severe pain and functional impairment.