A retrospective study is reported of 36 children and adolescents who had undergone spinal exploration and fusion for Type I of Type II spondylolisthesis of more than 10 per cent. The patients were examined and their radiographs studied. No progression of slip after operation was found even in the presence of a pseudarthrosis. Where altered mobility was present at the level above the fusion, this tended to be associated with pain. Posterolateral fusion relieved symptoms in 75 per cent, produced a sound fusion in 83 per cent and prevented further slip in all patients.

The Stanmore hinged total knee replacement was introduced in 1969 for severe destructive arthropathy of the knee, and the results of one hundred consecutive operations are presented after an average interval of two and a half years. Insertion of the prosthesis relieved pain in 94 per cent, improved the range of movement in 67 per cent, invariably restored stability and corrected valgus or varus deformity. Gross flexion contractures were improved but not always fully corrected. Serious complications were few, though of three cases of deep infection two came to amputation and one to fibrous ankylosis. There were no mechanical failures of components of the prosthesis.

A study of spondylolysis and spondylolisthesis in 142 children and adolescents is reported. In twelve of the seventy-nine patients followed for over a year the affected vertebra slipped further by 10 per cent or more. Increasing slip occurred mainly during the adolescent growth spurt, and was greater when spinal bifida or other vertebral anomalies were present. If at presentation the slip is less than 30 per cent then further slip beyond 30 per cent is unlikely. Decompression posteriorly is advised when signs of nerve pressure are present. Indications for spinal fusion are suggested; the intertransverse method of fusion was used in sixty-nine patients.

To measure the patellar height the ratio of the articular length of the patella to the height of the lower pole of the articular cartilage above the tibial plateau is measured on a lateral radiography of the knee, flexed beyond 30 degrees. Normal values lie between 0-54 and 1-06. The subluxing patella is at the upper end of the normal range, but, in chondromalacia, the male patellae were lower than average, but the female patellae were normal.

The pattern of fracture-dislocation of the upper part of the sacrum is demonstrated in three patients. The fracture line followed the segmental form of the sacrum and was usually caused by a posterior force against the pelvis which had been locked by hip flexion and knee extension. Fractures of the lumbar transverse processes also occurred, presumably from avulsion by the quadratus lumborum muscle. The damage to the sacral plexus found in all three cases recovered after several months. Radiographs of the injury are difficult to obtain in severely injured patients but oblique views of the sacrum help to determine the extent of the forward dislocation.

Twenty-six index patients with primary Madelung's deformity of the wrist were examined, as were sixty-five of their relatives. Standard radiographs were taken and measured to determine whether mesomelic dwarfism, a feature of dyschondrosteosis, was present. No case of mesomelia was found. No evidence of Madelung's deformity was found in the relatives of the index patients, who were all female. It is concluded that primary Madelung's deformity of the wrist is not an expressions of dyschondrosteosis, that it is not inherited, and that it does not occur in the male. One index patient with dyschondrosteosis was examined. Eight of her relatives were similarly affected, and three of these were male. It is suggested that previously recorded male cases of Madelung's deformity of the wrist were expressions of dyschondrosteosis or of secondary deformity.