In clinical practice, the determination of the treatment method for ischemic necrosis of the femoral head is based on the degree of osteonecrosis (stage and extent of necrosis), and the choice of treatment method is different for different stages of osteonecrosis. Generally speaking, early stage of osteonecrosis can be treated by head preservation surgery, so that many patients with osteonecrosis can be cured; late stage of osteonecrosis can be treated by artificial joint replacement surgery, so that almost all patients with late stage of osteonecrosis can be relieved of their pain and return to normal work and life. The relationship between specific stages and treatment methods is as follows: Generally speaking, when the femoral head has not collapsed or the area of osteonecrosis is small (<15-30%), head preservation surgery (medullary decompression, bone grafting, intercrural osteotomy) can be chosen. If the femoral head has already collapsed (above stage III), or if signs of collapse appear (crescent sign or subchondral bone fracture in the femoral head, cystic degeneration in the corresponding femoral head area), especially if the area of necrosis is large (>30%), the clinical efficacy of head preservation surgery will be significantly reduced, therefore, the best treatment method at this time is to choose artificial total hip replacement.