The clinical staging of femoral head necrosis is important for determining the prognosis and determining the treatment plan. ARCO staging is 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 MRI femoral head lesion range <15% B femoral head lesion range 15-30% C femoral head lesion range >30% Stage 2: femoral head patchy uneven density, sclerosis and cyst formation, no collapse manifestation on plain film and CT, MRI and bone scan A MRI femoral head lesion range <15% B MRI femoral head lesion range 15-30% C MRI femoral head lesion range >30% Stage 3: Crescentic sign on frontal and lateral views A crescentic sign length <15% articular surface or collapse less than or <2-mm B crescentic sign length - 15-30% of articular surface length or collapse 2-4mm C crescentic sign length >30 % joint surface length or collapse >4-mm Stage 4: collapse and flattening of the joint surface, narrowing of the joint space, necrotic changes in the acetabulum, cystic changes, cysts and bone spurs