Forty-eight images using magnetic resonance imaging (MRI) in 16 hips with Perthes' disease were evaluated over a mean period of two years. MRI depicted exactly the infarcted zone in the femoral head before typical radiological changes were evident. Early determination of the extent of the infarcted bone on MRI benefits those patients who require treatment. Follow-up MRI scans at six-monthly intervals, reflected the chronological stages of the repair process in each group classified according to Catterall.

A study of structures which obstruct reduction of hip dislocation was performed on 15 hips by magnetic resonance imaging (MRI). Before treatment started, MRI studies were performed on 10 patients, six of whom were treated conservatively, after which further MRI studies helped to establish a concentric reduction. In the other four conservative treatment failed and they were operated on; in them the MRI studies were compared with arthrographic and surgical findings. In all but one of these 10 patients, MRI enabled us to differentiate between an everted and an inverted limbus. In five other patients with unsatisfactory development of the hip following closed reduction, MRI was compared with earlier arthrographic studies. MRI provided accurate anatomical information which would not have been obtained by arthrography. It clearly has great potential in assisting the surgeon to select the appropriate form of treatment.