Magnetic resonance imaging in congenital dislocation of the hip.

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.