Forty-three patients with unilateral congenital short tibia with partial or complete absence of the fibula are reviewed. The factors influencing the degree of leg shortening at maturity are considered. Serial radiographic measurements of leg length in fourteen patients covering an average observation period of 9-3 years support the hypothesis that the relative difference in growth between the two limbs remains remarkably constant. By estimating the percentage difference between the normal and abnormal leg lengths on the first measurable radiograph it is therefore possible to predict the likely shortening at maturity. This method of prediction allows the surgeon to make the decision to proceed to Syme's amputation or to the use of an extension prosthesis at about one year of age when the child starts to walk.

A quantitative study of the vascularity and a qualitative study of the remodelling of the calcified cartilage and subchondral bone end-plate of adult human femoral and humeral heads were performed with respect to age. In the femoral head the number of vessels per unit area was found to fall 20% from adolescence until the seventh decade and in the humeral head 15% until the sixth decade. Thereafter an increase was noted in the femur but none in the humerus. More vessels were present at all ages in the more loaded areas of the articular surfaces: 25% more for the femur and 15% more for the humerus. The degree of active remodelling by endochondral ossification declined 50% from adolescence until the seventh decade in the femoral head, and 30% until the sixth decade in the humeral head, rising thereafter to levels comparable to those found at young ages. More remodeling was noted in the more loaded areas at all ages.

Two patients, a Japanese man and woman both aged eighteen, developed symptoms and signs of osteomalacia over a period of five years. Each of them had a benign osteoblastoma, one in the right fourth metacarpal and the other in the uppermost third of the right humerus. Resection of the tumours without any treatment by vitamin D resulted in rapid cure of the osteomalacia. Attempts to prove a phosphaturic humoral substance or vitamin D antagonist in the osteoblastoma of the humerus were unsuccessful, probably due to prompt excretion from the tumour cells.

A simple modification of Gallie's subtalar fusion is described as a salvage procedure in treating patients with pain from old fractures of the calcaneous involving the subtalar joint. Graft bone for the fusion is taken from the outer half of the calcaneus, thus avoiding disturbance of the tibia or iliac crest. Collapse of the donor site helps to narrow the widened heel present in these patients. The posterior approach allows the peroneal tendons to be freed from any adhesions, and at the same time release of the calcaneo-fibular ligament permits some correction of the valgus of the heel. The early results in six patients have been encouraging.

The development of genu valgum in a child after a fracture of the upper metaphysis of the tibia with a medial gap is due to the interposition of a flap of fibrous tissue consisting of pes anserinus and periosteum avulsed from the lower fragment. The ensuing biomechanical disturbance induces bowing of the shaft and asymmetrical growth at both ends of the bone. Four cases of established deformity are reported, together with two cases of fresh fracture successfully treated by surgical clearance of the fibrous tissue from the gap.

Deep infection, the most serious local complication of total hip replacement, prompted a study of the records of 135 patients (137 hips) thus afflicted in a nationwide survey of Canada. Particular attention has been paid to the natural history of the infection, and the problems of diagnosis are described. Twenty-one patients died after the insertion, or removal, of the prosthesis, and of the survivors of the original 135 patients only eighteen have been able to retain the prosthesis without further problems with the wound. The remaining patients had the prosthesis removed, and most dry wounds. Certain suggestions are made on management. The advice that a second total hip prosthesis should be inserted after a deep infection of the first implant is not supported.

Twenty-nine patients with thirty pseudarthroses after removal of infected total hip prostheses have been reviewed one to six years later. Six hips still had a discharging sinus. Complete removal of all cement was found to be essential for healing, and various points in the technique of its clearance have been made. In this respect radio-opaque cement was a great advantage, and lateral guttering of the femur was most effective. Compared with the situation before replacement considerable relief of pain was obtained in most patients but there was much less improvement in function.

The release of various penicillins and other antibiotics from two brands of polymerised bone cement has been studied in vitro and in vivo in mice. Bone cement plugs containing antibiotics demonstrated antibacterial activity as a result of diffusion of antibiotic from the plugs into the surrounding medium. With all antibiotics tested, from 2-5 to 10 per cent of the antibiotic in the cement was released in vitro in active form within twenty-four hours. Most of the activity appeared within three hours of the start of the test, but in some cases low levels of activity were detected after four days. Antibiotic cement plugs implanted in mice and rats produced low concentrations of antibiotic in the blood up to two hours after implantation, but activity was seldom detected subsequently. In general, penicillins and non-penicillin antibiotics showed similar diffusion characteristics, and the pattern of release in vitro and in vivo was consistent with the leaching of antibiotic from, or near, the surface of the bone cement.

The Norwich Health District (population 400,000) has been studied during a five-year period in an attempt to assess the value of examination of the hip in the newborn. It is confirmed that complicated deliveries produce higher rates of neonatal instability. But, in sixteen out of the seventeen cases with hip dislocations diagnosed late, delivery had been normal. It is estimated that after normal deliveries, hospital doctors detect only 50%, and family doctors only 28%, of cases of instability of the hip. It is concluded: 1) that the problem of congenital dislocation of the hip will not be eliminated by neonatal examination alone, even if skill in clinical examination could be improved and maintained; 2) that repeated examinations should be considered mandatory until the child is walking. In this regard, the value of the sign of limitation of abduction requires study; 3) that the public should be made aware by an appropriate health education programme that the problem of congenital dislocation of the hip has not yet been solved.

The anatomy of the autonomic sympathetic vasomotor nerve supply of bone was studied in rabbits by methods of histochemistry, and fluorescent and electron microscopy. Our observations show that the intraosseous vessels are richly supplied by adrenergic nerves. The large primary nerves are located on or about the surface of the vessel; the medium sized secondary nerves spiral around the long axis of vessels lying more deeply in the tunica adventitia; and the fine tertiary nerves form a rich plexus at the outer area of the tunica media. The tertiary nerves have various structures which probably contain neurotransmitter substance--that is, noradrenaline--and function as neuro-vasomuscular synapses. The sympathetic nerve supply of bone originates from the appropriate ganglion, and in the case of the tibial diaphysis it descends through the sciatic nerve and thereafter mainly through the medial popliteal nerve and enters the bone alongside the nutrient artery.

A rare form of injury to the distal tibial growth plate is described. Only two patients with such an injury have been reported previously. The injury, rotational displacement of the distal tibial epiphysis with posterior displacement of the fibula but without fracture, can be reduced easily and appears to have no lasting ill-effects.

A method of triple arthrodesis is described which involves inlay of the subtalar and midtarsal joints. It is applicable to the undeformed and valgus foot as is encountered in poliomyelitis, spasmodic flat foot, cerebral palsy and spina bifida. The operation was successful in controlling deformity and pain. The only significant complication was failure of fusion of the midtarsal joint which occurred in three of eighty-five feet (3-5%).

The results of operation performed within the first six months of life upon seventy-seven resistant club feet are presented. The indications for and the rationale of early operation are discussed. Particular attention has been paid to the relationship between the age at operation and the outcome more than four years later; the results were greatly superior when operation was undertaken early. Two surgical techniques are compared, the postero-medial release proving better than a simple posterior release. The relationship between clinical and radiological assessment is discussed, and also the influence of the results reported upon future practice.

In vitro studies on isolated bone cells were undertaken to investigate the presence of transplantation (histocompatibility) antigens. Bone cells were cultured with allogeneic lymphocytes and exposed to cytotoxic sera containing antibodies against transplantation antigens, to determine their antigenic profile. Preliminary results suggest that bone cells may not express lymphocyte stimulating antigens in an active form, at least after the isolation procedure performed. On the other hand, bone cells were killed by cytotoxic antibodies in a specific way, providing evidence for the presence of serologically defined (SD) transplantation antigens on the cell surface. Additional studies with absorbed sera suggest "sharing" of histocompatibility antigens between bone cells and lymphocytes. The relevance of the surface antigens of bone cells to clinical fields such as bone allotransplantation, susceptibility to various orthopaedic diseases and skeletal sarcomata is discussed.

A computerised image analyser has been used experimentally to determine its possible usefulness in quantifying bone density. Rats were prepared for this purpose and ash weight/volume readings were obtained on femora which had been radiographed and studied to estimate radiographic density by means of the image analyser. The findings indicated that rats can be prepared by administering oestradiol or by allowing an additional week's growth, both of which give a statistically significant increase of bone density. The computerised image analyser was able to detect these differences but the correlations, although real and linear, between ash weight/volume and radiographic density were not large. Further refinements in techniques will be needed before the system is applied clinically.

Thirty-one patients have been reviewed four and a half to thirteen years after total excision of the patella for fracture. This operation did not give the uniformly excellent results previously reported by some authors. The type of incision used was unimportant in the long term. Immobilisation in plaster-of-Paris for any period between one and eight weeks after operation had no adverse effect on the long-term results. There was no correlation between the amount of calcification or ectopic bone formation found in the patellar tendon and the degree of function or discomfort in the joint. There was no evidence that osteoarthritis is an inevitable sequel to patellectomy in man. Maximal recovery of knee function may take up to three years after patellectomy. In this series 22% of patients had excellent results, 39% good results and 39% poor results, according to defined criteria. The implications of these findings are discussed.

Seven patients with macrodactyly in the foot are reported. None showed any stigmata of neurofibromatosis and all were found to have excessive accumulation of fibro-fatty tissue as the most striking pathological feature. It is suggested that this may represent the basic lesion in this condition. The literature is reviewed and attention is drawn to the differences between macrodactyly in the hand and in the foot.

A case is reported four years after successful total replacement of the left humerus for chronic osteomyelitis of six years' duration, with an axillary sinus that had persisted despite repeated operations and more distally a pathological fracture that had failed to united after bone grafting. The disability was such that the patient had requested amputation, but he returned to his previous work as a driver six months after the total replacement and there has been no recurrence of infection.

Five cases of Kienbock's disease occurring in a group of fifty-three adults with cerebral palsy are described. The increased incidence of the disease is attributed to the flexed posture habitual in the affected wrist and to an effect on the pattern of blood supply to the lunate.

In a family study in which thirty-four patients with osteochondritis dissecans and eighty-six of their first-degree relatives were examined clinically and radiologically, only one relative was found to have osteochondritis dissecans. No association with other forms of osteochondritis, endocrinological abnormalities or dwarfism was found.