[The non-traumatic femur head necrosis in the adult. II: radiologic diagnosis and staging].

In recent years diagnosis, and in particular early diagnosis, of osteonecrosis of the hip has been much improved by modern imaging modalities. Magnetic resonance imaging is widely accepted as the primary imaging modality for the early detection of this disorder and can help to facilitate the therapeutic management in later stages. However, plain radiographs, bone scans and computed tomography are still important techniques, which cannot be avoided in most cases. This paper describes the relative values of the different modalities. The staging system used is the international ARCO system.