The causes of femoral head necrosis femoral neck fractures, sprains, falls, hip dislocations, acetabular insufficiency is prone to femoral head necrosis, the incidence is generally in 75-95% causes of femoral head necrosis there are a variety of causes. The most common are the following four aspects: 1, trauma: femoral neck fracture, sprain, fall, hip dislocation, acetabular insufficiency is prone to femoral head necrosis, the incidence is generally in 75-95%, most of the fracture surgery can occur after osteonecrosis. Hip injury (including hip dislocation, femoral neck fracture, rotor fracture, etc.) directly affects the local blood supply, especially the femoral head, and causes femoral head necrosis. In hip dislocation combined with fracture, the necrosis rate is as high as 90%. If the fracture dislocation is not rectified for more than 24 hours, the femoral head will be 100% necrosis. 2, hormonal drugs: long-term use of large amounts of adrenocortical steroids (such as: prednisone, dexamethasone and so on), can cause osteoporosis, arterial vascular obstruction, so that bone cells, bone marrow cells gradually necrosis. 3, rheumatism: half of them occur in cold and wet climate areas, prevalent in China, less in southern China, gradually increasing in the north, often combined with ankylosing spondylitis and rheumatoid arthritis. 4, chronic alcoholism: alcoholism can cause abnormal lipid metabolism, clinical data confirm that long-term heavy drinkers, femoral head necrosis rate significantly higher. The reason for this is that alcohol can cause increased blood viscosity causing bone microcirculation disorders and necrosis.