CT scans of 18 hips with typical congenital dislocation have been studied in 16 children. These show that the common position of dislocation is lateral, superior and slightly anterior, and that a "false acetabulum" can be distinguished even in young children. A defect in the posterior ischium causing distortion of the acetabulum was also present in most cases. The cartilage and the acetabular contents were well shown. Positions of reduction and the anteversion of the acetabulum and the femoral neck were studied. Hypotheses are presented on the mode of dislocation and on the cause of the pathological changes.

Ten children who had clinically stable hips at birth were radiographed at one month because they had factors predisposing to hip dislocation. In all cases one or both hips gave rise to a suspicion of dysplasia, though clinical abnormalities were slow to appear. Four of these hips subsequently dislocated. We believe that infants with late presentation of acetabular dysplasia and clinical abnormality belong to a different aetiological group from those with neonatal instability due to ligamentous laxity. The significance of this differentiation is that some infants presenting late have only recently dislocated, and the diagnosis has not necessarily been "missed" at neonatal examination.

From 1956 to 1965, congenital dislocation of the hip was treated in a standard manner in 191 cases. Reduction and plaster immobilisation was followed by a period in a Batchelor type plaster in full medial rotation. Femoral neck anteversion was then corrected by derotation osteotomy. In 95 children 117 hips were treated in this way and have been reviewed annually for 18 to 27 years. In 1983 they were assessed; there were 101 hips with good clinical results; radiologically, on a modified Severin scale, 62 were good, 39 were fair and 16 were poor. Derotation osteotomy proved to be the stimulus for growth of the acetabular roof in most cases; its safety, ease of performance and predictability suggest that it is superior to other methods of correcting the dysplasia.

The moulded baby syndrome comprises: head moulding (plagiocephaly); pelvic obliquity with unilateral loss of hip abduction in flexion; and occasionally scoliosis, torticollis and bat ears. The hips, however, are radiologically normal and do not require the treatment used in the management of congenital dislocation or dysplasia. A review of 67 hips confirms this finding.

Despite widespread use of gentamicin beads in the treatment of chronic infections of bone and soft tissue, no serious complications have been reported. This report describes a rupture of the femoral vein which occurred during the attempted removal of a chain of beads after radical excision of a chronically discharging Girdlestone arthroplasty. The patient later had a disarticulation at the hip. In the light of our experience with this and other cases we offer some suggestions as to the positioning of gentamicin beads, as well as the timing and method of their extraction.

Thirteen patients with dystrophic spinal deformities from neurofibromatosis treated by anterior and posterior fusion have been reviewed. The shortest follow-up was five years, the average seven years. Combined fusion produced satisfactory results in patients with a smooth kyphoscoliosis or with scoliosis without kyphosis, but it was unsatisfactory in patients with an angular kyphoscoliosis. Of the five patients with angular kyphoscoliosis, one had a persistent pseudarthrosis after operation and all had progression of the kyphosis despite the treatment. The morbidity rate also was high in this group of patients. Many of the complications were related to soft-tissue manifestations of the disease. It is recommended that very special attention be paid to the dystrophic angular deformity in neurofibromatosis; even anterior and posterior spinal fusion may fail to control its progression.

Serious neck injury in rugby football is becoming more common, especially in schoolboys. We report five who presented with spinal cord damage between 1977 and 1983, two in the 1982-83 season. The mechanisms of injury, the treatment, and the outcome are discussed. We suggest measures to reduce the incidence of this most serious injury and draw attention to the appropriate management in the critical phase directly after injury.

Operative treatment was performed in nine patients with cervical spondylotic myelopathy complicating athetoid cerebral palsy. The first two patients were treated by laminectomy, and the other seven by anterior interbody fusion. The symptoms in both the laminectomy patients improved after operation, but became worse again when cervical instability developed; they then had to have an anterior fusion in addition. In six of the seven patients who had primary anterior fusion a halo-cast (or a halo-vest) was used to keep the cervical spine immobile, and good bony fusion was obtained with satisfactory results. However, in one patient no halo apparatus was used, bony union did not occur and the radiculopathy reappeared. In cervical myelopathy complicating athetoid cerebral palsy laminectomy is contra-indicated; anterior fusion combined with a halo apparatus is, however, satisfactory.

Eleven articulated scoliotic spines were examined radiographically and morphometrically. Measurement of the curve on anteroposterior radiographs of the specimens gave a mean Cobb angle of 70 degrees, though true anteroposterior radiographs of the deformity revealed a mean Cobb angle of 99 degrees (41% greater). Lateral radiographs gave the erroneous impression that there was a mean kyphosis of 41 degrees while true lateral projections revealed a mean apical lordosis of 14 degrees. Morphometric measurements confirmed the presence of a lordosis at bony level, the apical vertebral bodies being significantly taller anteriorly (P less than 0.02). There were significant correlations (P less than 0.01) between the true size of the lateral scoliosis, the amount of axial rotation and the size of the apical lordosis. This study illustrates the three-dimensional nature of the deformity in scoliosis and its property of changing in character and magnitude according to the plane of radiographic projection.

Intramedullary spinal cord tumours may present as scoliosis without neurological signs. Those treating spinal deformities should be alert to this possible aetiology. The clinical features of 12 such cases are discussed with reference to early diagnosis and treatment. Patients with a painful scoliosis should be investigated with myelography as well as bone scintigraphy. Many intrinsic spinal cord tumours are now amenable to surgical removal. The prognosis for neurological recovery is poor once a severe deficit becomes established. The importance of early diagnosis and joint orthopaedic and neurosurgical management is emphasised.

A new technique for the transthoracic removal of a prolapsed intervertebral disc in the mid or lower thoracic spine is described. Investigations before operation include thoracic myelography, selective spinal angiography and CT scanning. Image intensification is used at operation to check the level of the prolapse. A tunnel in the coronal plane (vertebrotomy) is made through the posterolateral part of the disc and the adjacent vertebral bodies, to reach the spinal canal at the site of the prolapse. This gives good exposure and enables gentle removal of the disc prolapse and any associated osteophytes, under direct vision without need for retraction or pressure on the dura or spinal cord. Spinal stability is not compromised, and the blood supply of the cord is not disturbed. Five consecutive patients are reported, including one in whom the disc prolapse was calcified and had herniated into the spinal cord. All were treated successfully.

Radiolucent lines at the bone-cement interface beneath the tibial components were assessed in 91 consecutive Oxford meniscal knee replacements in 78 patients. Of 80 knees in which radio-opaque cement was used, a radiolucent line was observed in 77, with a radiodense line in the bone immediately adjoining. Radiolucent lines developed in the majority of patients within one year after operation. In 11 knees fixed with radiolucent cement (which precluded assessment of the radiolucent line) a radiodense line was observed beneath the lucent cement in all cases. Histological examination of the interface obtained from secure tibial components showed the lucent zone to be composed of fibrocartilaginous connective tissue and the radiodense line to be a thick lamella of bone. It is suggested that the living bone under a rigid prosthesis requires a layer of relatively compliant fibrocartilaginous material at its interface to accommodate load-bearing. Attention is drawn to the importance of the radiodense line: its presence may constitute positive evidence that healing at the level of bone section is complete and that equilibrium is established; its absence at a mature interface may indicate disequilibrium and impending failure.

The stability of union following the conservative treatment of tibial shaft fractures has been examined in 157 patients by a non-invasive method. With this technique it is possible to ascertain when the fragments are united and whether the strength of union is sufficient for full weight-bearing without protection. The mean time required for union was 14.0 +/- 9.2 weeks, with a range of 4 to 48 weeks. In 31 cases union was judged to be delayed; in 22 of these, intended operations were avoided because repeated stability determinations indicated progressive union. Of nine fracture variables examined, the only ones which significantly affected the time required to achieve union were the age and the weight of the patient. Irrelevant factors were the type and level of the fracture, the energy of trauma, soft-tissue injury and the presence of multiple injuries.

Seventy-two symptomatic knees were studied in 68 patients between 2 and 17 years of age. A firm clinical diagnosis was made in all knees before arthroscopy. The clinical diagnosis and the arthroscopic findings were compared to establish the accuracy of the clinical diagnosis. This was 42% in children under 13 years old (Group 1) and 55% in children between 14 and 17 (Group 2). Possible unnecessary arthrotomy was avoided in 58% of the knees in Group 1, and 31% of the knees in Group 2. The most common "incorrect" clinical diagnosis in Group 1 was that of a discoid lateral meniscus followed by a torn medial or torn lateral meniscus in that order. The most common "incorrect" diagnosis in Group 2 was a torn medial meniscus followed by a discoid lateral meniscus. It is considered that children presenting with knee symptoms should be managed by orthopaedic surgeons who are experienced in arthroscopic diagnosis.

The results obtained with a lightweight dynamic axial fixator in the treatment of fractures are reported. The apparatus comprises a single bar with articulating ends which clamp self-tapping screws and can be locked at an angle appropriate for axial alignment. A telescopic facility allows ready conversion from rigid to dynamic fixation once periosteal callus formation has commenced. Reduction and controlled distraction or compression are achieved by means of a detachable compressor unit. We treated 288 patients with fresh fractures and 50 with ununited fractures. The success rate for fresh fractures was 94%, with average healing times ranging from 3.4 to 6.5 months. In ununited fractures also, the success rate was 94% with average healing times ranging from 4.7 to 6.5 months. Complications were minimal. The device is versatile and can be applied in an average of 15 minutes. It permits ambulatory fracture care without sacrificing a sound anatomical result.

Equinus deformity of the ankle is one of the serious orthopaedic problems associated with Duchenne muscular dystrophy. Sixty-nine patients (age range 4 to 17 years) were treated, 43 conservatively and 26 operatively. They were followed up at six-monthly intervals for a minimum of two years and a maximum of six years. The patients were divided into three groups: independently mobile, mobile in calipers, and wheelchair-bound. It was found that conservative treatment could at best only minimise progression of the deformity. The indications for surgery, the operative procedure and the postoperative management are described; all varied according to the stage of the disease. The postoperative follow-up suggests that, though the deformity recurs, the patients have several years of benefit from the procedure.

Anterior and posterior drawer tests of the shoulder are described. Their purpose is to detect anterior and posterior shoulder instability and thereby to eliminate some of the failures of operative treatment. Their value in assessing unidirectional and multidirectional instability both before and after operation is discussed.

A case of bilateral avascular necrosis of the capitate is presented. A review of the literature has identified a clear-cut clinical syndrome. The aetiology and pathology of this syndrome is discussed and a new method of treatment is proposed.

Dislocation of both ends of the clavicle simultaneously is an injury usually sustained in a major accident; in this unusual case it resulted from a minor fall at home. The mechanism of injury and the treatment are discussed.

Six children with entrapment of the medial epicondyle in the elbow after closed reduction of a posterior dislocation were seen an average of 14 weeks after injury. The elbows were painful and the average range of flexion was 22 degrees. Two children had ulnar nerve involvement which recovered after operation. The epicondyle was removed from the joint and either reattached to the humerus or excised, and the muscles reattached. Two children had anterior transposition of the ulnar nerve, one for pre-operative hyperaesthesia, and the other to relieve tension on the nerve. At follow-up, at an average of 15 months after operation, flexion had increased fivefold, none of the children had pain and all were leading normal lives.

Cubitus varus is the most common complication of supracondylar fracture of the humerus in children. Although function of the elbow is not greatly impaired, the deformity is unsightly. It usually results from malunion, since growth disturbance of the humerus after this fracture is uncommon. The normal carrying angle can be restored by supracondylar osteotomy. This operation was done in 32 patients over a ten-year period, 16 of them using the technique described by French (1959). The results in 27 patients are reviewed in the light of previous reports. French's method proved safe and satisfactory.

One hundred and sixteen patients with 129 ununited fractures were treated either by rigid internal fixation and bone grafting or, in 14 tibial non-unions, by posterolateral bone grafting. In 37 actively infected cases this was combined with sequestrectomy and appropriate antibiotics. The final success rate was 98.4%. Technical errors or inadequate immobilisation after operation in patients with severe osteoporosis led to some early failures. No patient had a discharge or evidence of osteomyelitis after removal of metal. Rigid internal fixation with or without bone grafting is the treatment of choice for established non-union with bone loss when true synovial pseudarthrosis is present, when malalignment or shortening needs correction, and when prolonged immobilisation is either difficult or would lead to unacceptable stiffness in adjacent joints. Active osteomyelitis is not a contra-indication to internal fixation.

One thousand patients who received 1112 total joint replacements between 1966 and 1980 were followed up prospectively for an average of six years. These patients were not advised to take antibiotics prophylactically to cover subsequent dental or surgical procedures and, so far, only three cases of haematogenous infection at the site of the joint replacement have developed. Two hundred and twenty-four patients did subsequently undergo dental or surgical procedures and 284 patients developed infections in the respiratory tract, urinary tract or at multiple sites; none of these patients developed haematogenous infection. But of 40 patients who suffered recurrent skin ulceration and infection, three (7.5%) developed haematogenous infection of the replaced joint; two of these belonged to a group of 134 patients with rheumatoid arthritis. These results suggest that transient bacteraemia is not likely to infect a replaced joint in otherwise healthy patients. But an infected skin lesion producing chronic bacteraemia, or septicaemia due to a virulent organism, may well do so and patients with rheumatoid arthritis are at greater risk than those with osteoarthritis.

An unusual case of bilateral chronic sclerosing osteomyelitis of the clavicles is reported. A culture of resistant Staphylococcus aureus was obtained. Curettage of the lesions resulted in healing and symptomatic relief. There has been no recurrence on follow-up at one year.

In an attempt to improve the accuracy of diagnosis, 16 patients suffering from Morton's metatarsalgia were investigated clinically and electrophysiologically. The histological findings were related to these observations. The precise aetiology of Morton's metatarsalgia remains obscure, but the findings are compatible with an entrapment syndrome. Nerve conduction studies have a place in the investigation of patients with atypical presentation of pain in the foot. Further refinement of the electrophysiological technique should be possible.

Hemiarthroplasty of the hip and some other joints has been used for many years with satisfactory results, but the fate of articular cartilage when weight-bearing against metal has not been reported. Replacement of the head of the femur was carried out in one hip of each of 26 dogs, and the changes in acetabular cartilage studied at intervals of up to 24 weeks. There was early loss of proteoglycan, followed by surface damage to the cartilage, progressive degenerative changes, and growth of pannus from the articular margins. At 24 weeks after operation there was little remaining articular cartilage, while intense subchondral activity suggested that the bony skeleton was being remodelled to conform to the shape of the prosthesis. This study is not intended to suggest that hemiarthroplasty does not help patients.

Angular deformities of the distal radius of 15 sheep were induced by asymmetrical epiphysial distraction. Eleven sheep were between 10 and 20 weeks old; four were older than 24 weeks. Gradual distraction on the medial side of the limb caused partial separation of the epiphysis from the metaphysis, resulting in a valgus deformity. The distraction device was removed three to six weeks after insertion. Spontaneous correction of angulation with growth occurred in the younger sheep; but when the induced valgus angle exceeded 20 degrees correction was poor. In two sheep further distraction was applied on the lateral side and this produced complete correction. Premature closure of epiphyses did not occur after distraction and longitudinal growth of the bone remained normal. In the older sheep asymmetrical distraction succeeded in inducing angulation in only one case, and correction was poor.

A patient is reported who developed a fistula between the hip and the caecum 39 years after arthrodesis of her hip. She presented with a painful right hip and radiographs showed that the Smith-Petersen nail used for arthrodesis had moved up through the acetabulum and into the pelvic cavity. The nail was removed but within a week a fistula which discharged alimentary contents had developed between the hip and the caecum. The patient was treated conservatively, and three weeks later the fistula had closed.