[Osteonecrosis of the hip in adults].

Osteonecrosis of the hip (ON) in the adult is still an unsolved therapeutic problem. New pathophysiological findings have increased our knowledge of the disease course. Technical progress in imaging modalities and a better understanding of pathomorphology have improved the diagnostic procedure. The most significant progress for pathophysiology, early diagnosis and therapeutic decision making has been evolved by the routine use of MR-imaging. Using the international ARCO staging system, the pathomorphological and imaging changes during the different ON stages are described in this review. A diagnostic algorithm for ON is proposed. There are numerous conservative and surgical therapeutic approaches to ON, and the number of these is still increasing. A short overview of the most common therapeutic concepts is given. Finally, recommendations for therapeutic decision making for daily practice are proposed.