The clinical staging of femoral head necrosis is important for determining the prognosis and determining the treatment plan. ARCO staging is currently the commonly used staging method Stage 0: biopsy results are consistent with necrosis, the rest of the examination is normal Stage 1: positive bone scan or/and MRI A 30% range of MR femoral head lesions Stage 2: patchy uneven density of femoral head, sclerosis and cyst formation, no manifestation of collapse on plain film and CT, positive MRI and bone scan, no change in the acetabulum A 30% range of MR femoral head lesions Stage 3: crescentic sign on front and side Crescentic sign on radiograph A Crescentic sign length 4-mm Stage 4: collapsed and flattened joint surface, narrowed joint space, necrotic changes in acetabulum, cystic changes, cysts and bone spurs