A, the occurrence of femoral head necrosis causes: the causes of femoral head necrosis are many, there are three common clinical causes of femoral head necrosis: namely, drug causes (taking glucocorticoid drugs), alcohol stimulation (long-term heavy drinking) and traumatic (femoral neck fracture). The most painful of these is often the drug-induced osteonecrosis of the femoral head. I often encounter some young patients in the clinic because of minor lesions in the eyes or throat, long-term use of informal drugs, which add glucocorticoids to increase the efficacy but are not indicated in the instructions, resulting in patients unknowingly suffering from osteonecrosis of the femoral head. Alcohol itself can cause osteonecrosis of the femoral head, so patients with early onset osteonecrosis of the femoral head must abstain from alcohol to avoid aggravating the condition. Femoral neck fracture, especially the head downstream fracture has a very high chance of femoral head necrosis, here to remind patients after the internal fixation of femoral neck fracture to regularly return to the hospital for review, in order to early detection, early treatment. Second, the signs and symptoms of femoral head necrosis: 1, pain. Pain can be intermittent or continuous, aggravated by walking activities, sometimes rest pain. Pain is mostly pins and needles, dull pain or soreness and discomfort, often radiating to the groin area, inner thigh, posterior hip and medial knee, with numbness in the area. 2.Joint stiffness and activity limitation. The affected hip joint flexes and extends unfavorably, has difficulty squatting, cannot stand for a long time, and walks with a duck walk. The early symptoms are limited abduction and external rotation activities. 3.Crippling. Progressive shortening limp, due to hip pain and femoral head collapse, or late onset of hip subluxation. 4. Localized deep pressure pain, pressure pain at the stop point of the adductor muscle, positive 4-character test, positive Gaja’s sign, positive A11is sign, positive TKdelelatuq test. The joint movement is limited, and the affected limb may be shortened, with muscle atrophy and even signs of subluxation. Sometimes the axial stroke pain is positive. Treatment of femoral head necrosis: 1. Before femoral head collapse: Firstly, we should remove the causes of the disease, such as alcohol consumption and medication, and then avoid strenuous activities and weight bearing to avoid femoral head collapse as much as possible, and then we can consider treatment measures such as drilling and decompression and autologous bone graft. 2, after the femoral head collapse: at this time, conservative treatment is often difficult to achieve the desired effect, hip arthroplasty has become the preferred treatment measures, as one of the most successful human surgery in the 20th century, the effect of hip replacement for the treatment of femoral head necrosis has long been widely recognized around the world.