Routine examination for spinal deformity as part of a school health screening programme was introduced in Singapore in 1981. The three different ethnic groups included in the study provided figures for the prevalence of idiopathic scoliosis in an Asian population. A three-tier system of examination was used and a total of 110744 children in three age groups were studied. In those aged 6 to 7 years the prevalence was 0.12%. The prevalence in those aged 11 to 12 years was 1.7% for girls and 0.4% for boys, a ratio of 3.2 to 1. In girls aged 16 to 17 years the prevalence was 3.1%. In the latter two age groups there was a significantly higher prevalence in Chinese girls as compared with Malay and Indian girls. The optimal age for school screening seemed to be 11 to 12 years, but repeated examinations may be worthwhile.

A study of 130 scoliotic children with curves measuring 10 degrees or more has been performed in order to elucidate the importance of stature, growth and development. Girls with adolescent idiopathic curves measuring 15 degrees or more were taller than girls with smaller idiopathic curves and taller than those whose scoliosis was secondary to leg-length inequality (pelvic tilt scoliosis). No differences were observed as regards growth velocity or development. The increased standing height may be genetic but the uncoiling effect of the normal kyphosis to give a flat lateral profile is a more likely cause. The familial trend in idiopathic scoliosis may therefore be explained by the genetically determined shape of the spine in the median (sagittal) plane.

A radiological study of 50 patients with thoracic Scheuermann's disease revealed two types of lateral spinal curvature. A total of 43 lateral curves was present in 35 of the patients. Thirteen were apical at the same level as the Scheuermann's kyphosis and were due to vertebral-body wedging in the coronal plane; these curves had a mean Cobb angle of 15 degrees, occurred with equal prevalence in boys and girls and were directed equally to right and left. Thirty curves occurred in regions of compensatory lordosis (mean 5.6 degrees) situated above or, more commonly, below the Scheuermann's kyphosis. These scolioses had a mean Cobb angle of 16 degrees, were more often convex to the right than to the left and were significantly more prevalent in girls than in boys. The presence of these kyphoses and scolioses in the same spine, separated by only a few vertebrae, emphasises the importance of the sagittal plane in idiopathic spinal deformities and strongly suggests that idiopathic scoliosis and Scheuermann's disease share a common pathological process.

A review is presented of 13 young patients with congenital scoliosis who were treated by epiphysiodesis of part of the vertebral bodies combined with posterior fusion, both on the convex side; the plan was to arrest growth on the convexity which, combined with growth of the concave side, would result in progressive correction of the curve. The first patient was operated on at the age of four years and has now reached skeletal maturity with complete correction of her curve. Several others, still growing, are showing progressive correction. Only three curves, in which kyphosis was more severe than scoliosis, have deteriorated since operation. Although full assessment must await skeletal maturity of all the patients, this approach appears to have sufficient potential to justify an early report.

Seven patients treated in infancy by a lumbar theco-peritoneal shunt for idiopathic communicating hydrocephalus presented later in childhood after developing a characteristic orthopaedic syndrome. This included a severe, rigid and progressive lumbar hyperlordosis, severe bilateral restriction of straight leg raising and abnormalities of stance and gait. Four of the patients, who had severe hyperlordotic curves of over 90 degrees, required operations to correct their extreme deformity. The recommended method of correction is a three-stage procedure: first, anterior wedge resection osteotomies at several levels in the lumbar spine, then a period of "90-90" femoral traction, and finally a posterior fusion and stabilisation using Harrington instrumentation. The results were good, with few complications.

Fourteen patients with ankylosing spondylitis had an extension osteotomy for severe flexion deformity of the spine. The Smith-Petersen technique was modified by using a compression device which allows a slow, finely controlled closure of the osteotomy, and provides rigid internal fixation. There were no serious neurological complications. All the patients were able to see straight ahead after operation, and all had solid fusion at nine months, having maintained good correction.

Moire topography was added to school scoliosis screening in Singapore in 1982. The results from 1342 topographs, assessed in isolation, were used to study the accuracy of the method in predicting the radiographic location and magnitude of scoliotic curves. Accuracy in identifying the site of the curve was 68% in the thoracic spine, 54% in the thoracolumbar spine, and 15% in the lumbar region. There were 12.7% false-positive results and 4.3% false negatives. Of patients with a deviation of one moire fringe, 76.5% had a curve of 15 degrees or less; of those with a deviation of four moire fringes, 69% had a curve greater than 26 degrees. The prediction of the Cobb angle was less accurate when there was a deviation of two or three fringes. It is suggested that moire topography as a screening device should be reserved for use in the second tier of screening, since the forward-bending test is an effective and cheap method for the first tier of a mass school-screening programme.

The management of displaced subcapital fracture of the hip is still controversial because of the high incidence of complications after internal fixation or hemiarthroplasty. To avoid some of these complications we have used primary total hip replacement for independently mobile patients over 65 years of age. A total of 163 cases, operated on over four years, have been reviewed. There were relatively more dislocations after operation for fracture than after total replacement for arthritis, and these were associated with a posterior approach to the hip. Only seven revision operations have been required. Of 57 patients who were interviewed an average of 42 months after replacement, 62% had excellent or good results as assessed by the Harris hip score. All the others had major systemic disease which affected their assessment. This inadequacy of current systems of hip assessment is discussed. It is concluded that total hip replacement is the best management for a selected group of patients with this injury, and that further prospective studies are indicated.

Ten uncemented total hip replacements were performed in 1975 using an implant in which the cobalt-chrome femoral stem was coated to give a porous surface. In all but one case a high-density polyethylene head was used. The radiological changes in the upper femoral shafts were assessed between three and nine years later. Seven showed extensive stress-relieving changes, loss of calcar, stress fractures at the root of the lesser trochanter with subsequent detachment, and osteoporosis followed by avulsion of the greater trochanter. In these seven patients the lower part of the stem appeared to be soundly embedded, although in only one was there evidence of bony incorporation. It is suggested that if the fixation of a fully coated implant of this sort remains sound, gross atrophy of the upper femoral shaft develops after five years. This atrophy, associated with an implant which can be removed only at the expense of further bone destruction, presents substantial problems if revision is needed.

Fracture of the polyethylene acetabular cup is a rare late complication of total hip replacement. Five cases are reported. In each one this followed a fall, and involved a Muller arthroplasty which had previously been symptomless. It is postulated that ridges or other irregularities of bone, produced by keying holes, could lead to areas of thin cement and potential weakness of support for the cup.

The joint surfaces of 60 hips obtained from the cadavers of elderly Asians were studied to determine the incidence, the grade and the distribution of both non-progressive (age-related) and progressive degenerative changes. It was observed that in the Asian population of 40 to 90 years of age, non-progressive changes were common, being seen in 66% of the acetabular specimens and 50% of the femoral heads. Only one specimen of the 60 showed unexplained progressive degenerative change. We conclude that primary osteoarthritis of the hip is rare in Asians.

The relationship between the route of inoculation, the dose of inoculum and the development of infection after prosthetic replacement has been determined in an animal model. The rabbit hip served as the model and a Staphylococcus aureus isolated from an infected human hip arthroplasty was introduced using different protocols. The 50% infective dose (ID50) was determined for comparative purposes. Contamination of the wound site with only a few bacteria was likely to result in infection. It was considerably more difficult to induce infection when the operation was performed without inserting the prosthesis, which suggests that the implant inhibits the body's mechanism for dealing with the insult. It was difficult to produce infection by inoculating the organisms into the bloodstream: if this inoculation was delayed till three weeks after operation the animals were often grossly septicaemic by the time the arthroplasty was infected. The results emphasise the importance of minimising intra-operative contamination and the efficacy of antibiotic cover.

The factors involved in the mechanism leading to traumatic posterior dislocation of the hip are examined. In 47 adult patients who had previously suffered such a dislocation, ultrasound scans were used to measure femoral anteversion on both the affected and the uninjured side. In 36 normal adult volunteers, used as controls, similar measurements were made. Femoral anteversion on both the injured and uninjured side was significantly reduced in the patients compared with the volunteers. These findings are discussed in the light of previous work which indicates that medial rotation is a factor in the mechanism of posterior dislocation of the hip. It is suggested that reduced anteversion acts like medial rotation to make the hip more susceptible to posterior dislocation, and that the less the anteversion the more likely is the injury to be a dislocation rather than a fracture-dislocation. It is concluded that patients who suffer such dislocated hips belong at one extreme of the normal population, having either reduced femoral anteversion or even retroversion, and that this anatomical feature selects towards hip dislocation rather than to injury of the femoral shaft, knee or tibia during the appropriate type of accident.

The gait pattern of five amputees was recorded by visual observation and also by a quantitative measurement system. The results were compared with the gait pattern predicted from biomechanical analysis. Visual observation was found to be an unreliable clinical skill. The observers recorded only 22.2% of the predicted gait deviations and were unable to comment on 15.6% of all the required observations. The gait parameters which were difficult to assess visually, namely step length and step time, are considered by most workers to be of particular value as diagnostic clinical indicators in gait assessment. The measurement system used was accurate in recording gait deviations and picked up 3.4 times as many deviations as visual observation. This report demonstrates the inadequacy of visual observation as a diagnostic method and emphasises the need for measurements.

Fifty-three failed knee replacements were revised using minimally constrained implants with smooth uncemented intramedullary stems and metal-backed tibial components. Polymethylmethacrylate was used only to replace lost bone near the surface of the implant. Excluding four knees which had serious postoperative complications, 91% had successful relief of pain, 84% had over 90 degrees of movement and 80% could walk for more than 30 minutes. Review of the radiographs showed that there were no progressive lucencies at the interface between bone and cement, and no subsidence of components or changes in alignment. At the uncemented stem-to-bone interface, thin white lines developed near the metal, and their significance is discussed. This revision technique is an effective treatment for aseptic failure of primary total knee arthroplasty.

Six boys with fragmentation of the proximal pole of the patella are reported; the condition was bilateral in one. Four of the six presented with symptoms of Osgood-Schlatter's disease or Larsen-Johansson disease of the same or of the contralateral knee, but they had no symptoms or signs relating to the proximal pole of the patella; one also had features suggesting minimal chondromalacia patellae. Two boys had no objective abnormality in either knee. It is suggested that the fragmentation may be a further form of traction osteochondritis of the attachments of the quadriceps mechanism. Attention is drawn to its characteristic radiographic appearance, its association with other forms of juvenile traction osteochondritis (which are commonly symptomatic), and to its occurrence in boys aged 10 or 11 years.

Avulsion of the distal pole of the patella in spastic children with a flexed knee gait may upset the equilibrium of the knee and cause deterioration in walking. We emphasise the clinical features, discuss the mechanism and outline the principles of treatment.

The effects of advancement of the tibial tuberosity by inserting bony wedges was studied on cadaveric specimens of the knee. The geometry, the contact areas and the forces acting on the patellofemoral joint were investigated, and the forces acting on the tibiofemoral compartment were calculated. A 1 cm advancement was found to be optimal in reducing the high patellofemoral joint forces occurring at 90 degrees and 110 degrees of flexion, whilst causing least reduction of the contact areas; the stresses on the joint were reduced significantly. Advancement by 2 cm and by 3 cm drastically reduced the congruity and the size of the contact area. It was also shown that 2 cm and 3 cm advancement caused an increase in forces at the patellofemoral joint and also in the tibiofemoral joint in a direction tangential to the articular surfaces.

A series of 19 patients with severe rheumatoid arthritis had replacement of both hips and both knees. They are reviewed after a mean follow-up of 27 months. The preferred programme is to replace hips before knees. Pain was relieved in all the patients and function was improved in all but two. Severe rheumatoid disease and prolonged immobilisation before the operations were not contra-indications to a successful outcome, but the presence or the development of cervical myelopathy combined with gross upper limb deformity militated against a good result.

A study was made of knee stiffness after fractures around the knee in patients with spina bifida. Thirty-one patients with 45 fractures were followed up for 2 to 15 years after the fracture. Knee stiffness was found in 67% of patients; this amounted to loss of up to half the normal range of movement. The stiffness appeared at two months from the time of the fracture and was established by six months. However, in all patients it had resolved by three years, so that their mobility was not affected in the long term. It is concluded that though stiffness is common after fractures in patients with spina bifida, it should be treated expectantly as it will resolve within three years without specific treatment.

Hand function in 33 patients with myelomeningocele, aged from 4 to 17 years, was investigated by clinical examination and formal tests of co-ordination and dexterity. The average score for hand function was 59% of normal and only two children had clinically normal upper limbs. Twenty-eight patients (85%) had cerebellar ataxia, either alone or combined with other abnormal signs, most commonly upper motor neuron lesions. Hand function was significantly better in children of 11 years and older, in children under 11 with milder degrees of hydrocephalus, and in the younger children who were right-handed. Function was not shown to be better in those with lesions lower in the spine, nor in those with stable spines as has been previously reported. When co-ordination of the upper limb, manual dexterity and simultaneous movements of both arms were examined separately, these three were affected equally. Some abnormalities of hand function could be overcome by encouraging affected children to sit up and to practise skillful use of their hands as early in life as possible.

The Ontario Crippled Children's Centre has completed a two-year research project designed to develop effective strategies for training the preschool child to use a myoelectric prosthesis. Two programmes were developed: one home-based with the parent as primary trainer, and the other Centre-based with a therapist as trainer. Seventeen children were successfully trained and fitted with myoelectric prostheses. Both training programmes appear to be equally effective, proving that informed parents can assume responsibility for the training of their children. Economic implications are self-evident. The functional assessment of the children's skill with the myoelectric prosthesis is very encouraging so far. However, long-term studies are indicated for adequate assessment of the cost-effectiveness of early myoelectric fitting. As a result of this study, effective training methods can now be used in routine clinical service; a manual is available to provide guidelines.

The value of fitting adult upper limb amputees with electrically powered prostheses is assessed. In a series of 164 amputees, complete or useful acceptance of an electrically powered prosthesis was recorded in 80% of below-elbow amputees, 69% of above-elbow amputees and 72% of high level amputees. Patients expressed satisfaction with the combination of comfort, cosmesis and function. Results indicate that, accepting the high cost, an electrically powered prosthesis can provide important function to the upper limb amputee.

Reports of excision of the clavicle in the nineteenth century literature are reviewed, and certain operative complications discussed. Osteomyelitis was the most common indication, and was described first in this country by Syme in 1833. The first successful excision of the entire clavicle was performed by McCreary of Kentucky in 1813. The removal of tumour-bearing clavicles provided memorable challenges at a time when anaesthetics were not available, blood transfusion unknown and antibiotic therapy non-existent.

Severe crush injuries affecting the bones of the carpus are rare. We review the nine cases that have previously been described and report four additional cases which we have treated and followed up. All 13 present remarkable similarities, with disruption of the carpal arch through the capitate-hamate articulation distally and the piso-triquetral joint proximally. Three slightly different variations of this pattern of fracture-dislocation are identified. The flexor retinaculum must be involved to allow the displacement which is seen, and there is usually an extensive laceration of the thenar eminence. Treatment by closed reduction is usually successful. Long-term follow-up shows that, in the absence of nerve or vascular damage, the results are surprisingly good.

We report a case of periosteal chondroma of the proximal humerus with multiple cartilaginous masses extending around two-thirds of the metaphysial circumference. The humerus was short, presumably because the tumour interfered with growth at the epiphysial plate.

Excellent results can be achieved by plating fractures of the shaft of the humerus in patients with multiple injuries. This helps in nursing care and in the management of other injuries. In 38 patients admitted to a regional trauma centre, 39 humeral shaft fractures were plated. There were 27 men and 11 women, with an average age of 31.5 years. Fourteen of the humeral fractures were compound and 20 had significant comminution; 23 were fixed by a plate on the day of admission and all 39 by the twentieth day. Follow-up of 34 fractures showed that all had united, 33 primarily. All patients but one had a fully functional shoulder and no patient with a fractured humerus alone had lost any elbow movement. Complications were rare--one case each of non-union, fixation failure and infection. No permanent nerve injuries were produced at operation. The plating of fractures of the humerus in these circumstances has been shown to produce excellent results and has a place in the management of the patient with multiple injuries.

The protective effect of local hypothermia was studied in pig's limbs made ischaemic by long, repeated application of a pneumatic tourniquet. Twenty-one Landrace pigs were anaesthetised on two separate occasions six days apart and a pneumatic tourniquet at 500 mmHg pressure was applied to the same forelimb for three and two hours respectively. Ten of the pigs had local hypothermia from cold gel packs placed around the limb during the first tourniquet application; the other 11 had the ischaemic limb exposed to room temperature. In comparison with the normothermic limbs, the hypothermic ischaemic limbs had significant slowing of metabolism. The hypothermic limbs also showed less inflammatory response and a faster rate of recovery, both immediately after removal of the tourniquet, and by the end of the experiment, 10 days after the first tourniquet. Local hypothermia produced by this technique was shown to be safe and effective, while appearing to protect muscles exposed to prolonged tourniquet-induced ischaemia.

A case of locked hypersupination of the distal radio-ulnar joint is described in which the ulnar displacement was purely rotational rather than volar. The mechanism of injury is discussed in the light of cadaveric dissections which reproduced the injury.

In a randomised trial we compared the effects of two different antithrombotic regimens on the incidence of venographically established deep venous thrombosis (DVT) in 83 patients undergoing surgery for fracture of the femoral neck. Group A received dextran 40 peroperatively plus 0.5 g aspirin a day beginning before operation and continuing for 10 days after. Group B received heparin calcium 5000 iu subcutaneously plus dihydroergotamine (DHE) 0.5 mg intramuscularly, given 8-hourly, beginning before operation and continuing for 10 days after. Two patients in Group A and three in Group B developed proximal DVT, while the incidence of all DVT was 33% in Group A and 29% in Group B, a difference which was not significant. Haemorrhagic complications were much more common in the dextran/aspirin group: the volume of drainage fluid, the number of patients transfused and quantity of blood transfused, and the drop in haemoglobin level were all significantly greater in Group A. We conclude that the DHE/heparin regime is preferable to dextran/aspirin because it is safer and no less effective.

Two cases of aneurysmal bone cyst in the pelvis which healed spontaneously are described. Spontaneous regression of aneurysmal bone cysts has not previously been well documented. Our experience with these two cases suggests that radical intervention is not always necessary.

We have studied the use of filamentous polyglycolic acid (Dexon) for the induction of neotendon in the calcaneal tendon of sheep. Uniformly good results were obtained, with the formation of a thick neotendon. However, in a control group the power of spontaneous regeneration of the tendon was studied; it was found that, provided overlengthening of the gap was prevented, an equally good tendon resulted. It is concluded that this particular model is not an appropriate one for testing neotendon induction, despite its use for this purpose in the past. The favourable results of using filamentous polyglycolic acid as a tendon replacement suggest that it should be further investigated (in a more suitable model) since it may well have useful clinical applications.