Steinberg staging of avascular necrosis

Steinberg staging of avascular necrosis of hip is a commonly used system (at the time of writing, mid-2016) similar to the Ficat and Arlet staging.

It is based on the radiographic appearance and location of lesion. It primarily differs from the other systems by quantifying the involvement of femoral head which allows direct comparison between series. Seven stages of involvement are identified. Following staging, extent of involvement of femoral head is recorded as mild, moderate or severe.


  • stage 0: normal or non-diagnostic radiographs, MRI and bone scan of at risk hip (often contralateral hip involved, or patient has risk factors and hip pain)
  • stage I: normal radiograph, abnormal bone scan and/or MRI
  • stage II: cystic and sclerotic radiographic changes
  • stage III: subchondral lucency or crescent sign
  • stage IV: flattening of femoral head, with depression graded into
    • mild: <2 mm 
    • moderate: 2-4 mm
    • severe: >4 mm
  • stage V: joint space narrowing with or without acetabular involvement
  • stage VI: advanced degenerative changes

Quantification of extent of involvement is necessary for stages I to V:

  • stage I and II
    • A, mild: <15% head involvement as seen on radiograph or MRI
    • B, moderate: 15% to 30%
    • C, severe: >30%
  • stage III
    • A, mild: subchondral collapse (crescent) beneath <15% of articular surface
    • B, moderate: crescent beneath 15% to 30%
    • C, severe: crescent beneath >30%
  • stage IV
    • A, mild: <15% of surface has collapsed and depression is <2 mm
    • B, moderate: 15% to 30% collapsed or 2-4 mm depression
    • C, severe: >30% collapsed or >4 mm depression
  • stage V
    • A, B or C: average of femoral head involvement, as determined in stage IV, and estimated acetabular involvement

See also