Making the correct diagnosis and staging of femoral head necrosis at an early stage is the key to determining the treatment and estimating the prognosis. The diagnosis of femoral head necrosis mainly relies on medical history, physical examination, X-ray and MRI examination. Other auxiliary examination methods include radionuclide scan, CT, etc. Early clinical symptoms of femoral head necrosis are not typical, and internal rotation of the hip joint leading to pain is the most common symptom. After the femoral head collapses, limited range of motion of the hip joint may occur. X-ray examination should include anteroposterior and frog positions of the pelvis. X-ray changes usually appear several months after the onset of femoral head necrosis and include cystic changes, sclerosis or crescentic signs, the latter being the result of subchondral bone collapse. Recent studies have shown the limited value of technetium 99 scans for the diagnosis of femoral head necrosis, with MRI and histology confirming a false negative rate of 25% to 45%. MRI has high sensitivity and specificity (99%) in the diagnosis of early femoral head necrosis and has become the best test available for the diagnosis of femoral head necrosis. There are many staging methods for femoral head necrosis, such as Marcus, Ficat and Arlet, Steinberg, Pennsylvania University staging, etc. Most of them are based on X-ray and clinical symptoms, which have certain limitations. 1992 International Staging Criteria for Femoral Head Necrosis of the World Academy of Bone Circulation Research (ARCO) includes MRI performance and assessment of the degree of femoral head It is a more ideal staging method for femoral head necrosis.