What are the common stages of femoral head necrosis?

  Good New Year, for femoral head necrosis currently common there are the following 3 stages, you are often heard in the consultation of femoral head necrosis to several stages, what exactly means many people may not understand. Now a brief introduction.
  1.Ficat staging
  Stage 0 No pain, normal x-ray, abnormal bone scan or MRI
  Stage I Pain, normal X-rays, abnormal bone scan or MRI
  Stage II Pain, cystic degeneration or/and sclerosis on X-ray, abnormal bone scan or MRI, no subchondral fracture
  Stage III pain, collapse of the femoral head on X-ray, abnormal bone scan and MRI, crescentic sign (subchondral collapse) or/and subchondral step-like collapse of the bone
  Stage IV Pain, acetabular lesions, joint space narrowing and osteoarthritis on x-ray, abnormal bone scan or MRI
  2.Steinberg classification
  Stage 0 Normal or no diagnostic indications on X-ray, bone scan and MRI
  Stage I Normal radiographs, abnormal bone scan and/or MRI
  A Mild: <15% of femoral head affected area
  B Moderate: 15% to 30%
  C Severe: >30%
  Stage II Cystic and sclerotic changes of the femoral head
  A Mild: <15%
  B Moderate: 15% to 30%
  C Severe: >30%
  Stage III Subchondral collapse (crescent sign), no flattening of the femoral head
  A Mild: <15% (length of articular surface)
  B Moderate: 15% to 30%
  C Severe: >30%
  Stage IV Flattening of the femoral head
  A Mild: <15% articular surface or collapse <2mm
  B Moderate: 15%-30% articular surface or collapse of 2-4mm
  C Severe: >30% articular surface or collapse >4mm
  Stage V Joint space narrowing and/or acetabular changes
  A Mild: femoral head involved as in stage IV, estimation of acetabulum
  B Moderate.
  C Severe.
  Stage VI Severe degenerative changes
  3.International classification of femoral head necrosis (ARCO)
  Stage 0 Biopsy results are consistent with necrosis, other tests are normal
  I stage bone scan or (and) MRI abnormalities
  A Mild: <15%
  B Moderate: 15% to 30%
  C Severe: >30%
  Stage II Uneven density of femoral head patches, sclerosis and cyst formation, decreased bone density on X-ray, no collapse of femoral head on X-ray or CT, abnormal MRI and bone scan, no change in acetabulum
  A Mild: <15%
  B Moderate: 15% to 30%
  C Severe: >30%
  Stage III Crescentic sign seen in frontal and lateral views
  A Crescentic sign length <15% joint surface or collapse <2mm
  B Crescentic sign length 15%-30% articular surface or collapse 2-4mm
  C Crescentic sign >30% of articular surface or collapse >4mm
  Stage IV Flattening of the articular surface, narrowing of the space, necrosis and sclerosis of the acetabulum, cystic degeneration and marginal bony redundancy.
  Ficat staging is a four-stage classification system, as long as it is based on the changes of femoral head X-ray. steinberg method is based on the former, adding MRI to assess the extent of femoral head necrosis content. arco combines biopsy and bone scan in addition to the above.