1, high coagulation and low fibrinolysis state leads to osteonecrosis 90% of the osteonecrosis seen clinically is related to the use of hormones and alcohol abuse. However, some people who also use hormones and alcohol do not develop osteonecrosis. In our survey, some people who used nearly 30,000 mg of methylprednisolone hormone did not develop osteonecrosis, while some people who used only 175 mg developed osteonecrosis of multiple joints, some people who used alcohol throughout their lives did not develop osteonecrosis, while a few people who drank only small amounts of alcohol developed osteonecrosis. The most likely mechanism that has been the focus of recent national and international research is the intravascular coagulation theory. This theory has been confirmed in subsequent studies. Current studies suggest that coagulation and fibrinolysis abnormalities may play an important role in the development of osteonecrosis. These factors can be inherited or acquired, but a hypercoagulable and hypofibrinolytic state is most likely to be the final common pathway for the development of osteonecrosis by initiating the development of an intermediate mechanism of intravascular coagulation. The development of osteonecrosis is a complex physiopathological process based on high lipid, high coagulation and low fibrinolysis, with multiple factors acting together. The occurrence of hormonal osteonecrosis of the femoral head may also be related to the overall state of the organism or to the underlying systemic disease itself. Thrombosis and fibrinolysis is a complex process, and problems in any one link in the whole waterfall chain reaction may stimulate the final thrombosis, and genetic variants and defects associated with hypercoagulable and hypofibrinolytic tendencies congenital have been identified. 2, there are the following high-risk triggers susceptible to osteonecrosis (1) adrenocorticotropic hormone for the most common cause of femoral head necrosis in the country. According to statistics, prednisone 30mg daily for one month, about 1/3 of the people will cause osteonecrosis. There is a greater risk of high-dose shock therapy in the short term. (2) Alcoholic osteonecrosis is common in the northern part of China. May be related to alcohol-induced disorders of fat metabolism in the liver. According to statistics, if you drink more than 450ml of alcohol per week, long-term drinking can occur osteonecrosis, but individual differences are great. (3) Decompression disease or Caisson’s disease, which can involve multiple organs of the body. The cause of osteonecrosis is the separation of nitrogen from the blood during decompression, which cannot be exchanged in the lungs and accumulates in the tissues and small blood vessels. Nitrogen is five times more soluble in fat than in water, so it accumulates in the bone marrow, which is rich in fatty tissue, and causes osteonecrosis. This type of osteonecrosis can occur when returning from a high pressure state to an atmospheric pressure state or from an atmospheric pressure to a low pressure state, such as highland life and diving workers. (4) Sickle cell anemia. The incidence of osteonecrosis is between 12% and 20%, due to increased blood viscosity, slowing blood flow and the formation of blood clots. (5) Idiopathic osteonecrosis, which Chandler called “coronary heart disease” of the hip joint. Some of the causes are unknown, and some are due to a combination of factors. In recent years, due to the progress of research, many patients have found the cause, so the proportion of diagnosed idiopathic osteonecrosis is decreasing. 3, post-traumatic osteonecrosis caused by hip fracture is a common cause of osteonecrosis. Femoral neck fracture, traumatic dislocation of hip joint, femoral head fracture, etc. can cause femoral head necrosis. Claffey found that if the femoral neck is displaced upward by 1/2 the diameter of the femoral head, the superior supporting band artery supplying blood to the femoral head is torn. Statistically, about 80% of femoral neck fractures cause varying degrees of ischemia in the femoral head, but about 30% eventually collapse. Osteonecrosis is related to the external force of the trauma, the degree of displacement and the appropriateness of the treatment. Medical trauma, such as forceful massage, femoral neck osteotomy, synovectomy, etc., can also cause osteonecrosis of the femoral head. The incidence of osteonecrosis of hip dislocation is 4% to 10%, and its occurrence is related to delayed repositioning and the degree of trauma.