The determination of the treatment for ischemic necrosis of the femoral head is based on the degree of osteonecrosis (stage and extent of necrosis), and the choice of treatment differs depending on the stage of osteonecrosis. 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 (stage III or above), 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%), then the clinical efficacy of head preservation surgery will be significantly reduced, therefore, the best treatment method is to choose artificial joint replacement.