Early diagnosis has been made easier using magnetic resonance imaging (MRI), however no common satisfactory therapy has been developed for the early stage of the disease. Early surgery aimed at preserving the femoral head has been proposed, such as vascularised fibula grafting. However, the results of this invasive technique do not seem to be widely reproducible, and more minor interventions such as core drilling have high failure rates. Evidence is increasing that the nitrogen containing bisphosphonates may be beneficial in the treatment of ON. Data from clinical trials with patients with ON of the hip suggested that the bisphosphonate alendronate would reduce pain and disability and may reduce progression to femoral head collapse that usually would require surgical intervention.