Ischemic necrosis of the femoral head is a common clinical disease, which seriously affects the life and work of patients. The common causes of ischemic necrosis of the femoral head are: 1. Traumatic ischemic necrosis of the femoral head: severe trauma causing fracture of the femoral neck, fracture non-healing and necrosis of the femoral head may occur. Although some hip trauma does not cause femoral neck fracture, it may also injure the trophoblastic vessels of the femoral head and lead to ischemic necrosis of the femoral head. 2, non-traumatic ischemic necrosis of the femoral head: including the use of hormones, excessive alcohol consumption, hemoglobinopathy, decompression sickness, etc. Studies show that 10-30% of non-traumatic ischemic necrosis of the femoral head is related to hormone application. It is the average daily dosage or peak amount that is associated with osteonecrosis, not the cumulative amount or the length of treatment. Larger doses, even when used for a short period of time, carry a higher risk. The use of hormones equivalent to greater than 20 mg of prednisone per day carries a greater risk of osteonecrosis. The risk of osteonecrosis may be particularly high in kidney transplant patients, perhaps due to primary mineral deficiency and sparse cancellous bone structure. 3. Excessive alcohol consumption (alcoholism) is another major factor causing non-traumatic osteonecrosis. However, it is still difficult to define “excess”. A prospective study pointed out that drinking more than 400 ml of alcohol per week, the relative risk of osteonecrosis increased by 9.8 times. The relative risk of osteonecrosis increased from 2.7 times to 9.0 times for those who drank 10,000 years of alcohol compared to those who drank less than 4,000 years (the year of drinking refers to the amount of alcohol consumed per week x the number of years of drinking). 4. Non-traumatic osteonecrosis is also associated with a number of hemoglobinopathies. These include sickle cell anemia (sickle cell disease), sickle hemoglobinopathy, and sickle thalassemia. The incidence of osteonecrosis in these populations has been reported to be between 4% and 20%. Decompression osteonecrosis, which is largely historical and now rare, is associated with working environments that use compressed air (diving sickness), caused by poorly controlled decompression while diving into the deep sea.