Osteoarthritis of the hip joint is caused by a lesion of the cartilage of the articular surface of the femoral head, which later involves the internal part of the femoral head, causing changes such as cystic degeneration of the femoral head. Ischemic necrosis of the femoral head, on the other hand, is caused by the destruction and interruption of blood flow in the femoral head and the development of lesions in the femoral head: cystic degeneration, collapse of the femoral head, etc., which only involves the cartilage of the hip joint surface at an advanced stage. Both require artificial joint replacement surgery in advanced stages. Many physicians are unable to distinguish these differences and, therefore, tend to confuse the two. The treatment for both is the same in the late stages and requires artificial joint replacement surgery. Femoral head necrosis and hip osteoarthritis should be distinguished mainly from the X-ray film: femoral head necrosis X-ray film shows a small or interrupted bone texture of the femoral head, uneven bone density, femoral head cysts, sclerosis, flattening or collapse; osteoarthritis is mostly early joint gap narrowing, acetabular and femoral head joint surface at the same time appear less smooth or appear wavy and other abnormalities, some patients can appear half The bone surface corresponding to the narrowing of the gap often has irregular osteosclerosis, there is osteophytes in the non-weight-bearing area around the acetabulum, the head of the femur is mushroom-shaped, the osteophytes at the edge of the acetabulum form dense triangular bone blocks or curved long strips, covering the outwardly enlarged head of the femur. Cystic lesions, which may have a sclerotic bone wall. Necrosis and osteoarthritis are essentially different, the former is ischemic necrosis, concave head, joint gap changes, etc., while osteoarthritis is mostly degenerative, with age-related, hyperplastic hardening, etc.