The pathogenesis of slipped upper femoral epiphysis is unknown but the condition has been linked with various endocrine disorders. Nine patients with slipped epiphyses in association with primary juvenile hypothyroidism are presented. In all patients, slipping occurred or symptoms developed in the affected hip before the hypothyroidism was diagnosed. A generalised pathology was suggested by the absence of trauma (8 patients), by bilateral slipping (6 patients), and by obesity and short stature in all patients. All cases had delayed skeletal maturation and characteristic metaphysial changes were seen on their radiographs. The clinical diagnosis of juvenile hypothyroidism can be difficult but it merits consideration in patients who have a slipped upper femoral epiphysis in association with short stature, obesity, delay in skeletal maturity, or any one of these.

Six patients with severe haemophilic arthropathy of the elbow have been treated by limited excision arthroplasty using a sheet of silicone rubber as an interposition membrane. There were no complications. The symptoms and signs before and after operation have been assessed using the grading system advocated recently by the World Federation of Haemophilia. In all cases there was relief of pain and increased movement. Moreover, the subsequent incidence of spontaneous haemorrhage into the elbow has been reduced with considerable cost benefit.

The operative and anaesthesic technique for 44 patients undergoing posterior spinal fusion with Harrington rod instrumentation for idiopathic scoliosis is described. There were two groups of 21 and 23 patients, matched for diagnosis and status before operation. The management of both groups was similar but in one group anaesthesia with induced hypotension was employed, using a mixture of sodium nitroprusside and trimetaphan. The mean blood loss at operation and after operation in this group was significantly lower than in the other group, with a consequent reduction in the transfusion requirement. No adverse sequelae were observed. All patients showed a drop in haemoglobin concentration after operation, despite clinically adequate blood transfusion.

One hundred and twenty-five patients with 194 feet affected by congenital talipes equinovarus were treated by the senior author during the period 1959 to 1980. Of these, 70 patients presented either at birth or in the early neonatal period, and 55 were seen later, having been referred from other centres. Seventy-five patients were subsequently reviewed by two of us; the remaining 50 were assessed from records and research files. Patients seen within four weeks of birth were termed "early", the remainder "late". Of the early group of 70 patients, 44 (with 68 affected feet) were reviewed and 26 (with 41 affected feet) were assessed from records. Excellent or good results were achieved in 94 per cent of feet treated conservatively and in 82 per cent of feet which required pantalar release. Of the 55 late referrals 32 patients (with 55 affected feet) were reviewed and 23 (with 30 affected feet) were assessed from records. Satisfactory results were slightly less frequent, but were achieved in 75 per cent of cases. There was no statistical correlation between early soft-tissue release and a good final outcome, but there was a positive statistical correlation between good clinical results and a high talocalcaneal index. Osseous correction (a laterally based wedge tarsectomy or a triple arthrodesis) was necessary at a later date in four feet (four per cent) of those who presented early and in 13 feet (15 per cent) of late referrals.

Two cases of coccydynia are presented. Their definitive treatment was excision of the coccyx and the pericoccygeal tissues. The histology in both cases revealed a glomus tumour of the coccygeal body and the symptoms were completely relieved after operation. Glomus tumours of the coccygeal body may be the cause of some cases of coccydynia.

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.

A study was made of the mechanics of blood-bearing in a series of patients treated with a cast-brace for fracture of the distal femur. Knee hinges incorporating strain-gauges, a simple force-plate on the floor and a standardised weight-bearing test were used to record axial loads through the cast-brace itself and through the fracture during the phases of healing. The cast-brace carried loads of only 10 to 20 per cent of body weight and functioned mainly as an antibuckling hinged tube. Patterns of weight-bearing recovery showed that the fracture itself limited loads to safe levels. A measure of the recovery of strength at the fracture was determined and termed the "fracture load index". Graphs obtained in this way demonstrated four biomechanical phases of bony union which correlated well with the stages of clinical healing. The clinical application of these results have led to improvements in the design of braces and the use of a cylinder cast-brace for fractures of the distal half of the femoral shaft and of a new type of brace with a hinge at the hip attached to the thigh cast for fractures of the proximal shaft. A simple clinical test is described by which it is possible to monitor the healing of fractures in cast-braces.

Six patients are described with idiopathic osteoporosis which began between the ages of 4 and 16 years. In four children the disorder was mild with pain in the back, vertebral collapse, qualitatively normal iliac bone biopsies, variable calcium balance and spontaneous recovery. The two remaining patients had progressive bone disease with deformity. One with a previously normal skeleton developed changes similar to those of osteogenesis imperfecta; in the other patient, who rapidly developed structural collapse associated with severe metaphysial osteoporosis, treatment was ineffective and the histological appearances of the bone suggested osteoblastic failure. Quantitative bone histology in four patients showed no evidence of excessive active resorption; and the ratio of Type III to Type I collagen in the skin was normal, in contrast to the findings in osteogenesis imperfecta. The significance of this study in relation to previous accounts is reviewed.

The correction of angular deformities of long bones by incomplete osteotomy, followed three weeks later by manual osteoclasis, overcomes the problem of secondary displacement sometimes seen after correction by complete osteotomy and makes internal fixation unnecessary. This paper presents an experience of twenty-six operations in eighteen patients. In all cases the deformity was corrected with excellent cosmetic and functional results. Complete bony union was achieved and there were no problems with displacement at the osteotomy site. Four cases are described in detail to illustrate use of the technique in different clinical situations.

A case is described in which a large area of unstable skin overlying a tibial fracture was replaced by a single stage skin flap transfer, using microvascular surgical techniques. The shortening of treatment time and the improvement in the local blood supply compared to that provided by orthodox skin flaps are noted. The improved blood supply at the fracture site may have encouraged bony union.

Paralytic clawing of the hallux may occur in children with congenital disorders of the neuraxis. Tenodesis of flexor hallucis longus allows correction of this deformity in early childhood. Seventeen of these procedures have been reviewed and good results were obtained in fifteen.

The clinical features of eight patients with myositis ossificans progressiva are described and the effects of treatment with the diphosphonate EHDP, together with surgical removal of ectopic bone, are assessed. Early correct diagnosis remains unusual, mainly because the significance of the short great toes is unrecognised, and because myositis may be mistaken for bruising, sarcoma or mumps. The diphosphonate disodium etidronate (EDHP) was given to all patients in an attempt to suppress calcification of new lesions; in five of them ectopic bone was removed during the treatment. EHDP sometimes delayed the mineralisation of newly formed bone matrix after surgical removal but this delay could not be predicted. The variable effect of EHDP may depend particularly on the amount absorbed and on the activity of new bone formation.

We describe unexpected adverse psychological and social results in three adult men with severe Little's disease who were made more mobile by successful surgery.

In a clinical, radiological and biochemical study of forty-two patients from Oxford with osteogenesis imperfecta, it was found that patients could be divided simply into mild, moderate and severe groups according to deformity of long bones. In the severe group (seventeen patients) a family history of affected members was uncommon and fractures began earlier and were more frequent than in the mild group (twenty-two patients); sixteen patients in the severe group had scoliosis and eleven had white sclerae; no patients in the mild group had white sclerae or scoliosis. Radiological examination of the femur showed only minor modelling defects in patients in the mild group, whereas in the severe group five distinct appearances of bone (thin, thick, cystic and buttressed bones, and those with hyperplastic callus) were seen. The polymeric (structural) collagen from skin was unstable to depolymerisation in patients in the severe group, but normal in amount, whereas the reverse was found in the mild group. This division according to long bone deformity may provide a basis for future research more useful than previous classifications.

1. The results of internal fixation are described in 470 tibial shaft fractures.

2. The immediate internal fixation of compound fractures was followed by so high an incidence of serious complications that the use of this method is not recommended. The immediate internal fixation of fresh closed fractures was also followed by many complications.

3. Delayed rigid internal fixation proved satisfactory for difficult fractures in which an acceptable reduction could not be obtained by closed means ; skeletal traction was of value in such fractures until the skin was soundly healed.

4. Delayed internal fixation reduced both the healing time and the complications.

1. Sections were cut from the third metacarpal, the radius, the femur and the third lumbar vertebra of thirty-four male and twenty-one female cadavera. The mineral content of these different specimens was measured by ashing and the relationships between the quantity of bone mineral present at these sites were examined.

2. In the females the whole bone density and mineral/unit length at both the midshaft metacarpal and the midshaft radius correlated significantly with the whole bone density at all the other sites.

3. In the males these correlations were much less significant and no significant correlation was found between the whole bone density of either the metacarpal midshaft or the radial midshaft and that of the third lumbar vertebra or the distal femur, although a highly significant correlation was found between those of the distal femur and the lumbar vertebra.

4. It is suggested that in women, measurements of either mineral/unit length or whole bone density of both the midshaft metacarpal and radius provide useful information on the whole bone densities at other sites throughout the skeleton. This work was supported by the Scottish Hospital Endowments Research Trust, the National Fund for Research into Crippling Diseases and G. D. Searle and Co. Ltd., High Wycombe.

1. Nineteen patients with spina bifida, myelomeningocele or lipoma of the cauda equina have been reviewed. Convex pes valgus was found in twenty-five feet. All patients had a neuromuscular imbalance between the evertors and invertors of the foot.

2. Results of release procedures only and of those which combine release procedures with tendon transfers are compared; they show that there is no consistently satisfactory operation for correction of the deformity when it exists with neuromuscular imbalance.

3. An operation in which release procedures are combined with the transfer of the peroneus brevis to the tibialis posterior and of the tibialis anterior to the neck of the talus is described. It has given satisfactory results in two out of three patients with paralytic convex pes valgus.

1. The use of the Metals Research Macrotome for cutting 100 μ thick sections of fresh, unfixed specimens of arthritic human femoral heads and normal goat condyles is described.

2. A technique for isolating living cells from these slices by decalcification followed by enzymic digestion is reported.

3. The microscopic appearances of the fresh slices, the decalcified slices and the isolated cells as seen by incident or transmitted fluorescent lighting, by phase-contrast microscopy, by scanning electron microscopy and by histological and cytological techniques are illustrated.

4. These techniques might be applicable to the examination of biopsy specimens of pathological bone or to basic research on bone cells.

1. Methods for culturing cells isolated from slices of arthritic human or normal mammalian cancellous bone are described.

2. The capacity of the cultured cells to take up and hydroxylate labelled proline has been investigated.

3. Sections of the partially decalcified bone and of the isolated cells have been examined by transmission electron microscopy.

4. The possible significance of the results and observations are discussed. We are deeply grateful to Dame Janet Vaughan, who very kindly read this manuscript and made several valuable suggestions and criticisms. We are much obliged to Dr Sylvia Fitton-Jackson for her advice on the techniques of tissue culture and for giving us the composition of her chemically defined medium. Dr Palfrey kindly allowed one of us, M. J. Dickens, to learn transmission electron microscopy in his department at St Thomas's Hospital Medical School under the expert tuition of Mr G. Maxwell. Mr R. Hockhan and Mr M. Hepburn of the University of Surrey Structural Studies Unit helpfully instructed in the operation of the transmission electron microscope. Our special thanks are due to Mr E. P. Morris for his competent and enthusiastic technical assistance.