Table 2: Steinberg classification for hip osteonecrosis.
| Stage | Radiographs | MRI |
|---|---|---|
| 0 | Normal | Normal MRI and bone scan |
| 1 | Normal | Abnormal MRI and/or bone scan |
| 2 | Cystic/sclerotic changes | Abnormal MRI and/or bone scan |
| 3 | Crescent sign (subchondral collapse) | Abnormal MRI and/or bone scan |
| 4 | Flattening of femoral head | Abnormal MRI and/or bone scan |
| 5 | Narrowing of joint | Abnormal MRI and/or bone scan |
| 6 | Advanced degenerative changes | Abnormal MRI and/or bone scan |