Ninety-seven limbs, in eighty-one patients, with a diagnosis of congenital deficiency of the fibula have been reviewed. A classification was devised to distinguish the minimal hypoplasia of the fibula (Type I) from the well-known complete absence (Type II). Congenital anomalies of the femur were present in 76 per cent of patients with Type I deficiency and in 59 per cent with Type II. The shortening of the limb was by 13 per cent in Type I and by 19 per cent in Type II, and the percentage shortening was fairly constant during growth. A detailed description of the spectrum of other congenital anomalies was found to be characteristic: for example, the ball and socket formation of the ankle, tarsal coalition and anomalies of the foot. The treatment aimed simply to equalise leg length in Type I deficiency, while amputation of the foot and the fitting of a prosthesis were necessary in Type II to obtain satisfactory function.

We have studied the histological appearances of forty femoral heads with idiopathic avascular necrosis. The characteristic histopathological changes of recurrent necrosis were present in 83 per cent. Recurrent necrosis occurred widely after revascularisation had progressed as far as the subchondral zone. The aetiology of idiopathic avascular necrosis of the femoral head may be a chronic condition which produces repeated infarction. The deformation and incomplete revascularisation of the femoral head may be due to repeated episodes of infarction as well as to mechanical factors related to weight-bearing.

Forty hips, which had previously been the site of tuberculous or pyogenic arthritis and which had later developed a degenerative arthritis, were treated by low-friction arthroplasty some forty years after the original infection. The results suggest that, when healing of the primary infection has been followed by a long period of quiescence with acceptable function before the onset of degenerative change, the arthroplasty can be confidently expected to result in greatly improved function and that this improvement is long-lasting.

Seventy-nine cases of fracture of the femoral shaft treated by cast-brace and early walking have been reviewed. Discrepancy in femoral length was assessed by scanogram. The cases were analysed to relate the incidence of shortening greater than 2 centimetres to the type and site of the fracture, and the time which elapsed from injury until the cast-brace was applied. Such shortening was encountered most frequently when the cast-brace was applied within the first two weeks from injury or after six weeks and in those patients with comminuted fractures of the middle third of the femoral shaft.

Forty-one arthrodeses of the shoulder in thirty-nine patients suffering from rheumatoid arthritis (thirty women, nine men) have been reviewed. Using internal fixation and external splints the position of the shoulder was maintained in 55 degrees of abduction, 25 degrees of horizontal flexion and enough internal rotation to allow the patient to reach the mouth. The mean period of immobilisation in a thoracobrachial splint was nine weeks, and 90 per cent of the shoulders had solid bony fusion at review. After arthrodesis the total range of scapulothoracic movement improved by about 60 per cent, giving results rated as excellent in fifteen cases (36 per cent), as good in thirteen (32 per cent) and as fair in thirteen (32 per cent). Arthrodesis can be recommended as an easy, cheap and reliable method of treating a shoulder which has been severely destroyed by rheumatoid arthritis.

The records of 110 cases of ulnar neuritis in 100 patients have been reviewed an average of 4.4 years after anterior transposition, or release of the aponeurosis. Seventy of the patients were reviewed personally. In over half the cases no precipitating cause was apparent. At operation the nerve was constricted by the flexor carpi ulnaris aponeurosis in fifty cases but in twenty-five no abnormal pathology was found. Recovery was greatest when operation was performed within three months of the onset of symptoms. In those cases where no abnormality was found, and those in which adhesions in the postcondylar groove involved the nerve, simple release was less effective than anterior transposition. It is therefore recommended that release be restricted to patients with a short history and with an obvious aponeurotic constriction unaccompanied by adhesions. Anterior transposition is the operation of choice where no abnormality is seen or where the nerve is dislocated, compressed or tethered proximal to the aponeurosis of flexor carpi ulnaris.

The clinical characteristics of sleeve fractures of the patella are described and the methods of treatment are reviewed. Attention is drawn to the fact that the diagnosis may be missed because the distal bony fragment may be so small as not to be detectable by radiography. This is important because a large fragment of articular cartilage also separates. The best result was obtained from reconstitution of the extensor apparatus by internal fixation of the patellar fracture with repair of the quadriceps expansion.

An electromyographic investigation of patients with subluxation of the patella has been carried out on the parts of the extensor apparatus which actively contribute to the alignment of the patella, both before and after the operation to correct this disorder. The electromyographic pictures have revealed a sharp fall in the activity of the vastus medialis, with full recovery to normal values after a corrective operation. Even if the aligning function of the patella is altered by a variety of factors, the present study confirms the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism.

Twelve closely related members of one family were found to have small or absent patellae. Seven of these patients also had abnormalities of the pelvic girdle and upper femora. There was a resemblance to the nail--patella syndrome in the patellar abnormalities but not in the associated conditions, and it would therefore appear that the syndrome described is a new variety of congenital abnormality of the knee.

Standardised radiographs of the weight-bearing foot were analysed in fifty young patients undergoing osteotomy of the first metatarsal for hallux valgus. True metatarsus primus varus was not found more frequently than in a control series. The intermetatarsal angle was significantly greater in affected feet compared with controls. The structural abnormality in hallux valgus in the young is therefore due to a valgus disposition of the second and subsequent metatarsals, rather than varus inclination of the first metatarsal.

Experiments have been carried out on rhesus monkeys to determine the effect of the application of a pneumatic tourniquet on the ultrastructure of the muscles of the lower limb. Tourniquets were applied for periods lasting between one and five hours. The changes in the muscle lying immediately under the cuff of the tourniquet were more marked than those observed in muscle distal to the cuff. Three hours appears to be close to the limit of the time that a muscle can resist the sustained compression of a tourniquet.

From a total of 1571 surgically excised menisci, 112 (7.1 per cent) were found by gross and microscopic examination to contain one or more cysts. All of these cysts were associated with tears, either primarily horizontal or with a horizontal component. Tracks were often demonstrable leading from the tear to the cysts, and in some cases of osteoarthritis, detritus of bone could be found in their periphery. It is concluded that the cysts are fuelled by synovial fluid. The relationship of cysts to "myxoid" change of the meniscus is discussed.

Old calcified fibrin coagula are frequently found in simple bone cysts. They provide a scaffold on which new bone is laid down, in a process analogous to endochondral ossification. It is suggested that these coagula are derived in substantial part from the plasma-like contents of the cyst, after the release of plasma-clotting factors as the result of injury. Major haemorrhage is not involved and in many cases there is no antecedent fracture. The phenomenon is not seen in other common cystic conditions of bone and its recognition is thus helpful in the histological diagnosis of simple bone cyst. Cystic bone infarcts and their possible confusion with simple bone cysts are also briefly discussed.

The treatment of bone cysts by topical injection of methylprednisolone acetate was initiated at the end of 1973, and the late results are reported in this paper. In seventy-two cases followed up for one to three years favourable results have been obtained in about 90 per cent. The technique of local injection and the surgical equipment employed, in the case of focal recurrences, are considered. With this method, surgical treatment of bone cysts in youth is seldom necessary.

Four cases of extra-osseous osteosarcoma were found among 242 cases recorded as osteosarcoma in the Swedish Cancer Registry during the years 1958 to 1968. The tumours occurred in middle-aged and elderly patients. Three of the tumours were situated in the proximal part of the thigh and one in the scapular region. Histopathologically, all tumours were subclassified as osteoblastic osteosarcomas. The patients were treated by primary local excision which in one case was followed by a radical en bloc excision of the entire tumour bed. All cases subjected to simple excision died of metastatic disease five to twenty-four months after diagnosis. The patient treated by en bloc excision is alive and apparently free from disease fourteen years after diagnosis.

A retrospective study of patients with osteosarcoma was undertaken to determine whether there was a relationship between biopsy and survival. Fifty-seven patients treated at the Karolinska Hospital, Stockholm, between 1938 and 1959 were included in this study, all of whom were less than thirty years old, had a metaphysial osteosarcoma in a long bone but had no pulmonary metastases at the time of diagnosis; all were treated by amputation. No clinical variants of osteosarcoma were included. Twenty-four of the fifty-seven patients had an amputation without a prior biopsy; the others had biopsies before amputation. These two groups were fairly closely matched in age, sex, site and size of tumour, and in the level of amputation; some patients in each group received radiation before operation. Evaluation of these two groups of patients revealed that the performance of a biopsy, with or without a delay of not more than thirty days between the biopsy and the definitive operation, had no adverse effect on survival.

A randomly selected sample of 3494 children evenly representing a total population of 37 391 schoolchildren aged between eleven and twelve was screened for idiopathic scoliosis by the bending test. Ten per cent of the children showed clinical evidence of scoliosis and 6.4 per cent had positive radiological findings. Small curves were equally distributed between the two sexes, while large ones were more common in girls. Children with fair hair and blue eyes showed a higher percentage of positive findings than children with a dark complexion. A group of 112 children with curves between 7 and 16 degrees were followed up for an average of nineteen months. The pattern and evolution of these curves showed their close relationship to established scoliosis. Potential factors of instability and deterioration of the curves were evaluated.

Hemicircumferential division of the periosteum was performed on the upper tibia of the rabbit. Division of the medial side regularly caused a valgus angulation, but other injuries about the upper tibia had no effect. The cause of deformity after periosteal damage is discussed.

The passage of technetium-labelled methylene diphosphonate (99mTc-MDP) across rat bone was examined by autoradiography. The autoradiographs showed that shortly after an injection of the bone-seeking agent there was activity outside the bone, within the bone marrow and also adjacent to the highly vascular epiphysial plate; the distribution of the isotope in the incubated bone appeared to be non-uniform, a high concentration being seen adjacent to the epiphysial plate and also on the surfaces of the bone. The evidence suggested that a two-fold mechanism resulted in the uneven distribution of 99mTc-MDP. The first factor probably represented the regional distribution of blood flow with a transcapillary movement of the tracer from the capillary bed to the extravascular space; the subsequent incorporation of the tracer into bone appeared to depend on the nature of the bone matrix.