This prospective study was performed to determine the true incidence of deep vein thrombosis of the lower limb in children who had undergone halo-femoral traction to correct scoliosis before operation. Bilateral ascending phlebography of the lower limbs was performed on 54 children two days before spinal fusion and Harrington rod instrumentation. Two patients developed clinical evidence of thrombosis whilst on traction. This diagnosis was confirmed by phlebography. The other 52 children had no clinical evidence of thrombosis and their venograms were normal. The incidence of thrombosis was 3.7 per cent and clinically silent thrombosis did not occur.

A study of the natural history and aetiology of deep vein thrombosis in 499 patients after total hip replacement is presented. Deep vein thrombosis was diagnosed by scanning the leg for 125Iodine-labelled fibrinogen for a period of 14 to 18 days and by ascending phlebography. It has been shown that deep vein thrombosis occurs ater than in patients who have undergone abdominal operations, and the risk period is longer. The peak of onset of thrombosis is on the fourth day after the hip replacement. Attempts at prophylaxis using subcutaneous heparin or intermittent pneumatic compression of the calves delay the appearance of thrombosis. Analysis of possible aetiology factors shows that the age of the patient, the degenerative disease of the hip, the surgical approach, and under-transfusion of blood, all have a significant effect on the incidence of thrombosis.

Osteomyelitis was induced in the tibiae of rabbits by injecting a suspension of Staphylococcus aureus and sodium tetradecylsulphate, a sclerosing agent. These rabbits were then divided into two groups: one group remained untreated and the other was fed a diet containing sodium salicylate. Two and four weeks after induction of osteomyelitis the tibiae taken from untreated rabbits with osteomyelitis and incubated in vitro released significantly more prostaglandin E and F than the control uninjected or uninfected tibiae. Tibiae taken from rabbits treated with sodium salicylate showed minimal radiographic changes and a significantly decreased release of prostaglandin E and F compared to the untreated rabbits. Prostaglandins are known to be potent bone resorbing agents and the results of this study suggest that they may also be involved in the destruction of bone which is characteristic of osteomyelitis. The treatment of rabbits with osteomyelitis using anti-inflammatory drugs, which block synthesis of prostaglandins, in addition to antibiotics, may prevent the destruction of bone and possible sequestration thereby decreasing the risk of chronic disease.

The release of prostaglandins E and F from the tibiae of rabbits and the surrounding muscle in vitro after fracture and pinning, or pinning alone, has been compared to the release from unoperated tissues. The fractured tibiae released significantly more prostaglandins E and F than the control tibiae three to 14 days after operation. The pinned tibiae also released more of the two prostaglandins, although this was significant only after 14 days. Consequently it was only around the third day that the fractured tibiae released significantly more prostaglandin E than the tibiae which had been pinned, but not fractured. Similar results were obtained for the release from the muscles surrounding the tibiae. Prostaglandins are important mediators of inflammation as well as potent stimulators of bone resorption. Their increased formation in response to fracture and pinning may stimulate the vascular changes, bone resorption and the proliferation of osteogenic cells observed after trauma to bone.

Thirty-three children with traumatic dislocation of the hip who had been treated at the Hospital for Sick Children between 1960 and 1977 were reviewed. The amount of trauma causing dislocation of the hip in younger children was less than that for older children. The most frequent complication was soft-tissue interposition which usually required a posterior arthrotomy to clear the interposed tissue. Less frequent complications included avascular necrosis, redislocation of the hip and an irreducible hip. Nineteen children were reviewed with an average follow-up time of 10 years. Clinical examination indicated that 84 per cent of these hips were normal but the radiographs showed that 47 per cent of the dislocated hips had a coxa magna of two millimetres or more. There was no correlation between the development of coxa magna and the clinical result.

Computerised tomography is useful in the diagnosis of abnormalities of the hip in children, particularly in assessing the size and shape of the acetabulum, the position and congruity of the femoral head relative to the acetabulum, and the degree of femoral anteversion or retroversion. It is most useful when limited hip movement and previous operations preclude adequate clinical examination and assessment by routine radiographic techniques. It is not recommended for routine use in screening congenital dislocation of the hip or in diagnosis or follow-up of Perthes' disease or slipped capital femoral epiphysis.

Stereoradiography with a base shift of the source of illumination was used to produce pairs of radiographs to be measured by stereophotogrammetric techniques. The direction of shift was parallel with the longitudinal axis of the body, so that each radiograph in the stereopair could be used for other clinical purposes. A base shift of 10 centimetres with a distance of 100 centimetres between the focus and the film gave acceptable value of stereoscopic parallax. The radiographs were measured using a Hilger and Watts medical stereometer. This method was checked with test specimens, namely an osteotomised pelvis in which one acetabulum could be rotated and an osteotomised femur in which the whole upper portion could be rotated against the shaft. Measurements made on the acetabulum and its radiographs showed a correlation coefficient of 0.9838 over the range 0 to 30 degrees of anteversion, with a mean error +2.54 degrees and a standard deviation of +/- 1.52 degrees (n = 21). For the femoral neck, over the range from 10 degrees of retroversion to 80 degrees of anteversion, the correlation coefficient was 0.9979, the mean error +2.46 and the standard deviation +/- 1.48 degrees (n = 30).

An analysis of 142 dislocations from a multicentre study of 6774 total hip replacements is reported. The incidence of dislocation was 2.1 per cent. Patients with neuromuscular disorder, those in a confused mental state, and those undergoing revision operations are at special risk. The commonest surgical error, present in nearly half the patients, was placing the acetabular cup too vertically or too anteverted. A less common fault was placing the femoral component too anteverted. Neither the original pathology nor the approach to the hip appeared to affect the likelihood of dislocation. The dislocations were divided into early and late, single and recurrent, and the success rate of treatment is described in these groups. One hundred and eleven patients (78.2 per cent) eventually obtained stability. Of those with a single dislocation, 62 per cent remained stable after a single manipulation. Thirty-four per cent of the patients required an open operation to achieve stability and it is suggested that, in many cases, open reduction alone is not enough; the mechanical fault needs to be corrected.

A series of 81 patients has been reviewed to determine the value of endoprosthetic replacement of the proximal femur and hip in the treatment of bone tumours. Standard statistical methods were used to evaluate the survival of the replacements and the patients. Taking removal of the prosthesis, irrespective of the cause, as the criterion for failure the survival of the replacements was found to be 63 per cent after 10 years. If deaths are regarded as failures, then the survival value falls to 48 per cent. The survival of patients with chondrosarcoma and osteoclastoma treated by endoprosthetic replacement compares favourably with survival after amputation or excision of the tumour.

The scaphoid fracture is commonest in young men in the age group 15 to 29 years, who have the highest incidence of non-union, take the longest time to unite, lose more time from work, and spend the longest time as outpatients. A union rate of 95 per cent can be achieved using standard simple treatment. All but a few fractures are visible on the first radiograph, and failure of visualisation at this stage is not associated with a bad outcome. The postero-anterior and semipronated views are the most important to scrutinise. Crank-handle injuries have a particularly bad prognosis when they produce a transverse fracture of the waist of the scaphoid. Poor prognostic factors are displacement during treatment, the fracture line becoming increasingly more obvious, and the presence of early cystic change. The severity of trauma is an important factor to elicit from the history.

Specimens of femoral cortical bone from normal subjects and from patients with osteoporosis were mechanically tested in tension to destruction. The osteoporotic bone showed less strength and less stiffness than the normal bone; these reductions are related to the increased cavity area in osteoporosis. Further, the osteoporotic bone is not able to absorb as much energy before fracture as the normal bone; but this difference is not related to changes in cavity area.

Thirteen patients suffering from rheumatoid arthritis had 19 stress fractures of the tibia or fibula. These patients characteristically presented with sudden, severe, unexplained pain with localised tenderness just below the knee or above the ankle. In seven patients examination of the adjacent joint indicated a flare-up of disease activity or a pyogenic arthritis. In six patients the diagnosis was delayed by the late appearance of callus in minute fractures. All patients had rheumatoid deformities of the ipsilateral lower limb: valgus deformities of the knee and subtalar joints occurred most frequently. All patients had osteoporosis; all except two had received steroid treatment and five had abnormalities of calcium metabolism. We suggest that deformities of the knee and ankle predispose patients with rheumatoid arthritis and osteoporosis to stress fractures of the tibia and fibula.

Failure of union of the tibia with a large defect is difficult to treat, especially in the presence of sepsis and adherent scars. Conventional methods of fixation and bone grafting are not easily applicable. Experiments on Macaca monkeys showed that a vascularised pedicle graft of the shaft of the ipsilateral fibula could be fixed across a defect in the tibia and remain viable, even if it was isolated from surrounding soft tissues. Transfer of part of the shaft of the ipsilateral fibula on a vascular and muscle pedicle was carried out in 11 patients with large tibial defects and sepsis. There was one failure because of severe infection, but the other 10 patients gained sound union in about four months. The tibia was then protected by a caliper for the 18 months of full reconstitution. The bone infection healed and there was no evidence of avascular necrosis. Although the salvaged limbs were scarred, stiff and ugly, none of the patients suffered from pain, recurrent oedema or persistent infection.

Eighty-three Guepar valgus-hinge prostheses and 30 prostheses with collinear femoral and the tibial components were inserted in 97 patients at Vancouver General Hospital between March 1975 and May 1978. One hundred and nine arthroplasties were reviewed between January 1979 and April 1980, after an average follow-up of 19 months. It was found that the amount of bone resected made arthrodesis difficult, that there was a very high incidence of patellar instability and that the disintegration of the Silastic bumper created a severe chemical synovitis. The results were excellent in 32, good in 23, fair in 8, and poor in 30. Patellar subluxation occurred in 28 per cent of the valgus prostheses, and in 10 per cent with the straight prostheses; it did not occur with the straight prostheses in rheumatoid joints. The chemical synovitis led to failure with devastating complications necessitating further operations in some knees.

Five patients severely affected by haemophilia, in whom six knees showed advanced haemophilic arthropathy, have been studied. The patients presented with painful limitation of movement and increasingly frequent episodes of spontaneous bleeding in the affected knees. These all showed secondary degenerative changes and varus deformity. A Corrective osteotomy of the proximal tibia was performed under full haematological cover without complications. Follow-up ranged from 6 to 36 months, with a mean of 18 months. At follow-up all patients were free of pain and had retained their range of movement. In the three patients with a longer follow-up there was radiological improvement. The most significant feature was that there was almost complete cessation of bleeding episodes into the knee in all patients and no progression of the arthropathy. The cost benefit implications of this corrective procedure are discussed.

The different methods described in the literature for the reduction of severe spondylolisthesis are reviewed. The case histories of two girls with neurological deficits in their legs due to Grade IV spondylolisthesis are described. Reduction and fusion by the posterior route in a one-stage operation were performed on these patients. For this purpose special instruments have been designed to exert a controlled force on the displaced vertebra in two perpendicular directions. Technical details of the procedure are reported. In both patients intervertebral and posterolateral fusion were carried out. Fusion was successful and redisplacement did not occur. There have been only few descriptions in the literature of a technique that reduces and stabilises spondylolisthesis in one stage. However, only patients with Grade III and IV spondylolisthesis require reduction and in less severe cases fusion without reduction is sufficient.

There are many difficulties associated with the localisation of the symptomatic segment in patients presenting with cervicobrachial pain with no evidence of impaired conduction in the nerve root. Ancillary radiological investigations such as myelography, epidural phlebography, and epidural myelograms are of unreliable diagnostic value. However, discography can be of value if the technique described here is used. Infiltration of the cervical nerve root with local anaesthetic has also proved useful in the localisation of the symptomatic segment. The techniques used in cervical discography and infiltration of the nerve root are described and their reliability is assessed.