We report the cases of teenage twin girls presenting within months of each other with severe symptoms from lumbosacral disc prolapses, requiring laminectomy in one and chemonucleolysis in the other. CT scans showed similarities in spinal configuration, including the presence of disc bulges at the L4-5 level. This suggests a strong hereditary factor in prolapse of intervertebral discs, but a review of the literature showed little information on that aspect.

Twenty-one cases of the Charnley low-friction arthroplasty were revised because of recurrent or irreducible dislocation. Three main reasons for this revision, usually in combination, were identified: loss of the abductor mechanism due to trochanteric detachment; shortening of the limb due to high placement of the socket or low section of the femoral neck; and malorientation of the components. Sixteen patients had no further problems after revision. One patient had a single dislocation, four had more than one dislocation although they managed to cope with them and did not require a further revision.