The cycle of femoral head necrosis is 3-5 years, and it takes 3-5 years for a patient to go from the beginning of femoral head necrosis, cystic degeneration, fragmentation, collapse, to osteoarthritis, the osteoarthritic stage. Each patient has a different onset and causes, and there are long and short cycles: for example, femoral head necrosis caused by trauma occurs after a fracture, such as a femoral neck fracture, and necrosis occurs 2 years after an intertrochanteric fracture of the femur. In hormone-induced osteonecrosis, the necrosis will occur after 3 years of prolonged and heavy use of hormones, and in a few patients, it will occur after 1.5 years of medication. Alcohol-induced osteonecrosis of the femoral head often occurs after the patient has been drinking for about 10 years, so the cycle of osteonecrosis of the femoral head is usually 3-5 years, but it depends on the person.