Osteonecrosis is a specific disease. As defined by the International Society for the Study of Bone Circulation, osteonecrosis is the death of bone cells and bone marrow components following disruption of the blood supply and the subsequent repair process and outcome. As defined by the American Academy of Orthopaedic Surgeons (AAOS) in 2005, osteonecrosis of the femoral head is a disease that results from the death of bone cells and subsequent structural changes in the femoral head, causing collapse and dysfunction of the femoral head. Femoral head necrosis is a disease characterized by necrosis of osteocytes and bone marrow cells due to insufficient local blood supply to the subchondral bone of the femoral head from various causes. During the repair process, the mechanical properties of bone trabeculae decrease after the osteoclasts absorb the necrotic bone tissue, and fatigue fractures occur under stress, and cumulative fractures eventually lead to the collapse of the femoral head and subsequent osteoarthritis.