1.Trauma. Such as femoral neck fracture caused by external impact, hip dislocation, hip joint sprain and contusion, etc. 2, a lot of alcohol. The accumulation of alcohol in the body caused by long-term heavy drinking leads to the increase of blood lipids, which causes the increase of blood viscosity and slows down the blood flow, causing the blood coagulation to change and blocking the blood vessels, resulting in insufficient local blood supply and interruption of femoral head nutrition, causing femoral head necrosis. 3.Large or long-term use of adrenal glucocorticoids, etc. 4.Chronic cumulative strain injury. 5.Bone metabolism disorder. 6.Complicated necrosis after hip joint surgery. 7.Osteoporosis. 8.Bone structure changes lead to blood vessel compression resulting in blood flow disorders. All patients should understand these symptoms in order to have an understanding of their condition and better accept the treatment of the doctor, so that the necrosis of the femoral head is not difficult to treat and can be cured.