Distraction fractures of the upper lumbar spine are most often associated with the wearing of seat-belts. Twenty patients with this spinal fracture were reviewed and half of them had intra-abdominal injuries. Eight patients required an exploratory laparotomy. Three distinct patterns of distraction fractures have been identified. Open reduction, local spinal fusion and Harrington instrumentation are recommended for unstable fractures and for those with neurological involvement. Four cases of non-union are included ln the series. Legislation for the compulsory wearing of seat-belts should encompass improvements in design and stricter criteria for installation.

The results of the use of Harrington rods in the treatment of spinal fractures were reviewed. It was found that with burst fractures where the anterior pillar was deficient there was a significant incidence of loss of reduction. Anterior bone supplementation is recommended in these fractures when major loss of height or angulation occurs. Several technical faults were detected which, in most cases, also led to a loss of reduction. Almost all patients with an anatomical reduction were free of pain. There was no correlation between the loss of reduction and the lapse of time before operation, the levels of instrumentation, the length of the fusion, the severity of the initial deformity, the degree of initial correction or the presence or absence of a neurological deficit.

One hundred and sixty-seven patients with adolescent idiopathic scoliosis were allocated prospectively to one of three different groups for correction before undergoing posterior spinal fusion and Harrington instrumentation, In group 1 single curves were corrected by a Risser turnbuckle plaster jacket and double curves by halo-pelvic traction. In Group 2 patients performed Cotrel dynamic traction for three weeks and this was followed by correction in a plaster cast. In Group 3 patients were given Cotrel dynamic traction for one week only and the operation was performed without a plaster cast. There was no significant difference in the overall correction achieved among the patients in the three groups except that double curves corrected slightly better in Group 2. The correction achieved by Cotrel dynamic traction after three weeks was not significantly different from that obtained at 48 hours. An anteroposterior radiograph of the spine taken during Cotrel dynamic traction was a valuable guide to the mobility of the curve and is preferable to radiographs of the patients bending laterally, particularly with respect to curves over 70 degrees. The paper concludes that correction before operation is not required routinely in adolescent idiopathic curves unless the deformity is a severe and rigid one in which case a radiograph during Cotrel traction is a useful assessment.

Twenty-eight patients with adolescent idiopathic scoliosis treated by anterior spinal fusion with Dwyer instrumentation were reviewed. The average length of follow-up was 6.9 years. This technique produced better correction of lateral curvature and rotation than Harrington instrumentation, particularly in the thoracolumbar and lumbar region. The length of spine requiring fusion was also shorter. There is, however, a tendency for Dwyer instrumentation to lead to kyphosis. Morbidity was significant and included one case of paraplegia, four cases of deep infection and one case of instrument failure. All of these complications, except one case of deep infection, occurred in patients with curves with an apex above the seventh thoracic vertebra.

In this series, 15 patients with ossification of the posterior longitudinal ligament underwent anterior decompression to relieve moderate or severe myelopathy, which in 11 included urinary disturbance. The operation consisted of partial resection of the vertebrae, release of the ossified plaque from the surrounding tissue and the insertion of an iliac bone graft. The extent of ossification was confirmed by computerised tomography before and after operation. The plaque was completely detached and moved forward in half of the patients, but only partially moved in the remainder. Symptoms improved considerably. Urinary disturbance disappeared in all patients, but sensory disturbance was left in most. Two patients had prolonged symptoms which were not relieved despite the complete release of the ossified defect.

Ten cases of a complication of Garden screw fixation of subcapital fracture, namely subtrochanteric fracture through the lower screw hole, are presented. Their possible aetiology, prevention and difficulties in management are discussed. It is recommended that, during the insertion of Garden screws, care should be taken to avoid multiple attempts at passing the guide wire. If subtrochanteric fracture occurs internal fixation with a nail plate or screw plate is advised. Ideally the nail or screw should be inserted along the track of one of the existing screws.

Ferrography is a technique for analysing wear by means of the magnetic separation of wear particles. To evaluate its application in human joints, the results of the ferrographic analysis of saline washings of symptomatic human knees were compared with the results of the arthroscopic examination of the same knees. Ferrography was found to be an extremely sensitive monitor of articular erosion, with a resolution far greater than that of arthroscopy. This was particularly apparent with knees suffering from a torn anterior cruciate ligament: arthroscopy detected no damage to the cartilaginous surfaces whereas ferrography detected a substantial level of "microdamage". The spectrum of wear particles showed qualitative and quantitative alterations depending upon the condition of the knee. Ferrography thus holds much promise as a potential differential diagnostic technique of great sensitivity, with particular relevance to the very early changes which precede clinical symptoms. Study of wear particles is also justified by evidence indicating an active role in the pathophysiological progression of arthritis.

A method of analysing the results of knee replacement operations, which makes it possible to estimate the annual failure rate and the proportion of implants which will survive successfully for 10 years, is applied to the post-operative data for 365 operations, using Freeman, Sheehan and Manchester prostheses, carried out from 1972 to 1980 at Harlow Wood Orthopaedic Hospital. Two criteria of success are defined. On both, and for all prostheses, the annual failure rate is found to be much lower in the first two than in the later years. Thus, account must be taken of the period since operation if the success of different prostheses is to be validly compared. This is not possible using conventional statistical methods. But significant trends in annual failure rates and significant differences between prostheses can only be identified from samples larger than are usually available in individual series. Hence it will be necessary for many centres to co-operate in pooling results if reliable conclusions are to be reached and valid comparisons made.

One hundred and seventy-four consecutive patients with symptoms of derangement of the knee were examined with an arthroscope under local anaesthesia using a continuous pressure-irrigation system. A 0.2 per cent prilocaine-saline solution was used as irrigation fluid. In the first 19 patients the serum level of prilocaine was monitored for six hours after the start of irrigation. Eighteen of the 174 patients had a transcutaneous partial meniscectomy at the same time as the examination. All the patients tolerated the examination well. The distension of the knee produced by the pressure-irrigation system provided a high degree of diagnostic accuracy. The serum levels of prilocaine were low throughout the monitoring period reaching a mean peak value of 0.28 micrograms per millilitre after one hour. There were no adverse side-effects. This technique provides a safe and efficient method to meet the increasing demands of arthroscopic procedures of the knee.

A programme for early mobilisation using a temporary prosthesis was evaluated in 17 children who had had an amputation above the knee for sarcomata. The temporary prosthesis had a performed adjustable polypropylene quadrilateral socket which was able to accommodate changes in the size of the stump during the first few months after amputation. The adjustable sockets were assembled onto wooden knee-shank-foot units or onto modular components covered with foam. The wooden units were better for routine use as more adjustment was possible between the socket and the knee and because they were more durable in active children. Prosthetic fitting usually took one hour and was carried out 10 days after the amputation to coincide with the start of the chemotherapy programme. The prosthesis was cosmetically acceptable, easy to use and provided a simple and economical way of rehabilitating the amputees and restoring their morale. After two to three months a new prosthesis with a laminated socket suspended by a waistband was supplied. The skin tolerated the closer fit of this socket and the small fluctuations in the size of the stump that occurred with each course of chemotherapy were easily accommodated by varying the thickness of the stump sock. A self-suspending laminated socket was provided after completion of the chemotherapy. The permanent sockets were assembled onto wooden components but the girls usually preferred the modular system covered with foam. The chemotherapy and rehabilitation programmes were successfully co-ordinated so that the children spent as little time as possible away from their normal activities.

Two cases of congenital pseudarthrosis of the ulna due to neurofibromatosis are reported. Similar radiographic changes in the ulna were found, with distortion of the capitulum and part of the trochlea and bowing of the radius. In one patient the head of the radius was dislocated and in the other it dislocated readily during pronation. A possible mechanism to explain the findings was suggested. On the basis of these and a review of the literature it is recommended that the main aim of treatment should be maintenance of the normal relative lengths of the radius and ulna by early excision of the pseudarthrosis to remove the restraining effect of the abnormal ulna. This will allow normal development of the lower end of the humerus and radius and prevent dislocation of the radial head.

Twenty-three patients, aged from 10 to 60 years, underwent open reduction for untreated posterior dislocations of the elbow. The dislocations had been unreduced for periods varying from one month to two years. All patients underwent a standard procedure based on the Speed technique. Complications after operation included one case of gross sepsis and five cases of ulnar neuritis. Most patients gained a useful range of flexion-extension of the elbow. Neither the age of the patient nor the duration of the unreduced dislocation influenced the result.

Twenty-four patients treated for tibial shortening secondary to poliomyelitis were reviewed at least 20 years after operation. All subjects were active and only one expressed doubt about the value of tibial lengthening, considering the period of hospitalisation to have been a significant drawback. Approximately five centimetres were added to the length of the treated tibiae. Only one of the nine patients with lengthening of over five centimetres was able to walk at a rate of more than five kilometres per hour, compared with seven of the remaining 15 whose tibiae had been lengthened five centimetres or less.