The treatment of femoral head necrosis There is no single method to cure ONFH of different types, stages and volumes of necrosis, and a reasonable treatment plan should take into account the stage, volume of necrosis, joint function, as well as the patient’s age and occupation. Non-surgical treatment of femoral head necrosis It is important to note that the efficacy of non-surgical treatment of ONFH is still unpredictable. I. Protective weight-bearing There is still debate in academia as to whether this method can reduce femoral head collapse. The use of double crutches can effectively reduce pain, but the use of wheelchairs is not advocated. For early stage (0, I, II) ONFH, non-steroidal anti-inflammatory and analgesic agents can be used. For high coagulation and low fibrinolytic state, low molecular heparin and corresponding traditional Chinese medicine can be used. Physical therapy includes extracorporeal shock wave, high-frequency electric field, hyperbaric oxygen, magnetic therapy, etc., which are beneficial to relieve pain and promote bone repair. Surgical treatment of femoral head necrosis Most ONFH patients will face surgical treatment, which includes two types of surgeries: preserving the patient’s own femoral head and artificial hip joint replacement. Surgery to preserve the femoral head includes medullary core decompression, bone grafting, and osteotomy, and is indicated for patients with ONFH in ARCO stages I, II, and early stage III, with 15% or more of the necrosis volume. If the method is appropriate, artificial joint replacement can be avoided or postponed. I. Femoral core decompression (core decompression) It is recommended to use a fine needle of about 3 mm in diameter and drill multiple holes under fluoroscopic guidance. It can be combined with autologous bone marrow cell transplantation and bone morphogenetic protein (BMP) implantation. This therapy should not be used in advanced stages (stages III and IV). Second, with vascularized fibula transplantation for stage I, II, III ONFH, with good efficacy. Principles: (1) decompression of the medullary core of the femoral head, which interrupts the vicious cycle of ischemia and intraosseous hypertension (a possible cause of ON); (2) removal of necrotic bone that hinders the recanalization of the femoral head; (3) filling the defect with fresh cancellous bone, which plays an osteoinductive role; (4) filling with a viable cortical bone column to support the subchondral bone surface and accelerate the recanalization process, while limiting weight-bearing for a period of time after surgery to protect the healing structure. (4) filling with a viable cortical bone column to support the subchondral bone surface and accelerate the process of revascularization, while limiting weight bearing for a period of time after surgery to protect the healing structure. Bone grafting without vascularization is more commonly used in transtemporal rotor decompression bone grafting and transtemporal femoral neck bulb decompression bone grafting. Bone grafting methods include compression grafting and support grafting. The bone grafting materials used include autologous cancellous bone, allograft bone, and bone replacement materials. These procedures are suitable for ONFH in stage II and early stage III, and have better results in the middle stage if applied appropriately. Osteotomy The necrotic area is moved out of the weight-bearing area of the femoral head, and the non-necrotic area is moved out of the weight-bearing area. The osteotomies applied in clinical practice include internal or external osteotomy and transfemoral rotational osteotomy. This method is suitable for ONFH with moderate necrosis volume in stage II or early or middle stage III. This procedure will bring more technical difficulties for later artificial joint replacement. V. Artificial joint replacement Once the femoral head has collapsed heavily (late stage III, stage IV, stage V), and joint function or pain is heavy, artificial joint replacement should be selected. For patients under 50 years of age, limited femoral head surface replacement, metal-to-metal surface replacement, or dual-action femoral head replacement are available. These arthroplasties are transitional procedures that preserve more bone for later revision, but each has its own indications, technical requirements, and complications and should be chosen carefully. Arthroplasty has a positive effect on advanced ONFH, and it is generally believed that non-cemented or hybrid prostheses have better medium- and long-term outcomes than cemented prostheses. Artificial joint replacement for femoral head necrosis is different from joint replacement for other diseases, which requires attention to some related issues: 1. In addition, there are controversies in academic circles regarding the treatment of asymptomatic ONFH. Some studies suggest that ONFH with large necrotic volume (>30%) and necrosis in the weight-bearing area should be treated actively and should not wait for symptoms to appear.