1. The equipment used in the correction of scoliosis by the anterior route is described.

2. The important points in surgical technique are emphasised.

3. The results of operation on fifty-one patients are analysed.

4. Attention is drawn to the high rate of fusion, the stability of correction, and the brevity of the period of convalescence.

1. A high incidence of paraplegia following operations for the correction of severe scoliosis in adults led to an investigation of the normal blood supply of the human spinal cord.

2. This entailed three methods of study: micro-dissection of the vessels of the spinal cord in thirty-five cadavers; radiological measurements of the spinal canal in fifty healthy subjects; and a study of the macerated spinal column in six adult cadavers.

3. The blood supply of the spinal cord is shown to be least rich, and the spinal canal narrowest, from the T.4 to approximately the T.9 vertebral level. This is named the critical vascular zone of the spinal cord, the zone in which interference with the circulation is most likely to result in paraplegia.

1. A series of 226 upper tibial osteotomies is reviewed with special reference to the complications occurring in each of the six different operative techniques that have been used.

2 Wedge osteotomy above the tuberosity is the safest operation, but care must be taken to avoid a fracture into the joint.

3. Wedge osteotomy through the lowest part of the tuberosity may be indicated in the presence of large subarticular cysts or collapse of a tibial condyle.

4. The significance of weakness of dorsiflexion of the foot and the dangers of injury to the anterior tibial artery in osteotomies below the tuberosity are discussed.

1. A systematic collection of the clinical findings in fifty patients with pyrophosphate synovitis,among some 300 patients with obscure disorder of the knee, has been made over a period of eighteen months. The numbers of men and women were equal, the mean age being seventy years (range thirty-seven to ninety), and the mean age at the onset of symptoms fifty-nine years.

2. A difference in the clinical picture between the sexes was found. In men an acute synovitis predominated, in women chronic joint complaints.

3. A high incidence of accompanying disease was found, but none had a significant relationship to the arthropathy, although the high frequency (20 per cent) of synovitis following an acute severe illness of some other kind was striking.

4. No specific radiological sign except for calcifications in articular cartilage and menisci was found in these patients, and no relationship to osteoarthrosis could be established.

5. The great variability of symptoms and the surprisingly high incidence attracts attention to pyrophosphate synovitis as a cause of joint symptoms, especially in elderly patients.

1. A series of 298 unstable ankle fractures treated during the last ten years is reviewed.

2. Open reduction and rigid fixation with two screws, with early mobilisation after operation and avoidance of plaster, achieved a high percentage of satisfactory results. Accurate reduction diminishes the incidence of traumatic arthritis and pain.

1. Thirteen cases of fracture of the lateral process of the talus seen over a period of thirteen months are reported.

2. The mechanism of the injury would appear to be inversion strain of the foot with dorsiflexion of the ankle.

3. The diagnosis would no doubt be made more often if the possibility of this fracture were kept in mind, and if radiographs of good quality were taken with the ankle at 0 degree and the leg rotated inwards 10 to 20 degrees.

4. With regard to treatment, early operation appears to give good results, a single large fragment being reduced accurately and small or comminuted fragments being removed.

1. In a severe crush fracture of the calcaneus part of the lateral cortex may be displaced to lie under the tip of the lateral malleolus. This may cause local pain and tenderness, either by direct bony abutment or by compression of the peroneal tendons.

2. Such pain is usually relieved by excision of the tip of the lateral malleolus, a minor procedure.

3. Four of the five patients reported were completely relieved of lateral pain, and the fifth has only slight residual discomfort.

4. It is important to be aware of this lesion and not to advise subtalar or triple fusion when simple excision of the tip of the fibula would suffice.

1. Osteotomy for osteoarthritis of the hip induces a fibrin layer over the exposed bone which forms the basis of a fibrocellular protective mantle that can differentiate towards cartilage.

2. The process is accompanied by bone remodelling, which reduces sclerosis, resolves osteolytic foci and, in company with bone formation in the fibrous mantle, restores the subchondral plate.

3. Many important aspects of the pathogenesis of osteoarthritis and of its partial repair by osteotomy remain to be elucidated.

1. The surgical treatment of idiopathic aseptic necrosis of the femoral head has been reviewed in the light of experience gained from 240 hips operated upon.

2. When pain is not severe and the necrosis of bone as seen in serial radiographs is not rapidly progressive, simple observation and palliative medical treatment are indicated.

3. When pain disables the patient and collapse of the head is progressive, operation is indicated. If radiographs show necrosis limited to the anterior part of the head and sparing an arc of at least 20 degrees of the lateral part, either an osteotomy bringing the shaft into adduction and flexion or an "adjusted cup" arthroplasty is indicated, with a preference for the latter because it gives better results in a shorter time.

4. If at arthrotomy the necrosis appears to involve the posterior slope of the head, prosthetic replacement, preferably total, should be undertaken.

1. A controlled trial of ninety-nine patients with myelomeningocele has shown that immediate closure did not result in any significant (at P<0.05) reduction in mortality or alteration in muscle power.

2. If required, closure of the back may be delayed for forty-eight hours after birth or longer to allow a detailed clinical assessment of the infant.

3. The muscle power in the lower limbs is a useful guide to prognosis both in relation to mortality and the incidence of hydrocephalus.

4. Mortality is greatest in the first year of life.

5. In the urinary tract the commonest anomaly is neurogenic bladder. Other congenital anomalies were not more common than in children generally.

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. Attention is drawn to a type of foot in which painful plantar callosities form under one or more metatarsal heads. The affected metatarsal heads are shown to be depressed, or dropped, and this dropping is not caused by toe deformities.

2. An operation is described which elevates a dropped metatarsal head by a wedge osteotomy through the base of the metatarsal.

3. The various deformities of the tread are described, and the possible causes of this condition are discussed.

4. It is stressed that corrective metatarsal osteotomy is not appropriate for patients with deformities of their toes, who require correction of the toe deformity.

1. A modified technique of tendon transference for irreparable damage of the radial nerve is described. The tendon of the pronator teres is transferred to the two radial extensors of the wrist and to the tendon of extensor carpi ulnaris.

2. The method succeeds in preventing radial deviation on attempted dorsiflexion of wrist and helps to provide a powerful grip.

1. A case of multiple bone lesions in a patient infected by Avian-Battey bacillus is reported.

2. It is suggested that the prognosis in future Heaf-negative cases may be improved by studies of the cellular response to the infection.

1. A farmer who owned cattle infected with brucellosis presented with a painful, swollen wrist. Osteolytic lesions were seen radiologically. The wrist was explored. Histological features were those of a subacute granuloma. Brucella abortus biotype I was grown.

2. The clinical diagnosis, bone and joint radiology, pathology and microbiology are discussed.

1. The humoral immune response of rats against sheep iliac bone grafts has been examined.

2. Fresh, marrow-containing grafts elicited a brisk and sustained antibody response. Attempts to wash out the marrow were not uniformly successful in removing cellular antigens from the grafts.

3. Decalcifying and freezing bone grafts at —20 degrees Celsius do not impair immunogenicity to any significant extent. Immunogenicity was found to be reduced in grafts subjected to freeze-drying.

4. Deproteinised Oswestry bone grafts and Kiel grafts gave rise to antibody production in a few recipients, and in the case of the former this response did not occur until after six or seven weeks from grafting.

5. The highest degree of osteogenesis in composite bone xenograft-autografts was found by Salama and colleagues (1973) to occur in Oswestry bone grafts. It is suggested that osteogenesis in xenografts may be impaired by an immune response.

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.

1. The electric potentials in undeformed rabbit tibiae were measured in vivo and in vitro.

2. Surgically traumatised soft-tissues, particularly muscle, constituted the major source of voltage in vivo (up to 22 millivolts).

3. Electrical insulation of the tibia from attached soft parts abolished the high potentials on the bone.

4. Similarly high voltages could be reproduced in an excised tibia by substituting a battery for the injured muscle.

5. Changes in voltage also could be induced by altering blood flow rates or by rapid infusion of saline into the medullary space.

6. Death of the cellular elements in bone did not alter the voltage significantly.

7. The electrical contributions of the nervous system, and of dipole components of the extracellular matrix (such as collagen), either were inconsequential or of such low magnitude as to be "masked" by the larger "injury" voltages. Supported by grants from the United States Public Health Service (AM-07822) and the National Institute of Arthritis and Metabolic Diseases (TIAM-05408).

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.