We measured the stability of fixation in femoral neck fractures treated with von Bahr screws, investigated the influence of impaction and correlated peroperative stability with the clinical results. Stability was measured at operation using a metal probe fitted with strain gauges. Its tip was anchored in the subchondral bone of the femoral head and its lateral end was fixed in the lateral femoral cortex. The shearing force produced by longitudinal compression applied to the foot of the operated leg was recorded. The results in 41 consecutive patients all followed for 30 months, showed that fractures with early loosening or nonunion had all had significantly poorer stability than the fractures that had healed. Impaction improved stability in only 23 out of the 41 fractures; in the others stability had deteriorated or was unchanged.

We describe a method of internal fixation for femoral neck fractures which has been newly developed to reduce the frequency of early complications. Two cannulated screws are inserted in the axis of the femoral neck to reach into the subchondral bone of the femoral head. The screws are inserted over guide pins and the tip of the screw is self-tapping and designed to provide good anchorage in the femoral head. We used this method in 44 consecutive patients in a prospective study with no exclusions, followed for a minimum of 24 months. All fractures healed within 12 months, and there were no cases of early loosening or nonunion. In four cases, late segmental collapse had developed during the mean follow-up period of 30 months.

The effect of hypobaric spinal anaesthesia or narcotic-halothane-relaxant general anaesthesia on the incidence of postoperative deep vein thrombosis was studied in 140 elective total hip replacements in a prospective randomised manner. Deep vein thrombosis was diagnosed using impedance plethysmography and the 125I fibrinogen uptake test, combined, in selected cases, with ascending contrast venography. The overall incidence of deep vein thrombosis was 20%. Nine patients (13%) developed deep vein thrombosis in the spinal group and nineteen (27%) in the general anaesthetic group (p less than 0.05). The incidences of proximal thrombosis and of bilateral thrombi were also less with spinal anaesthesia than with general anaesthesia. It is concluded that spinal anaesthesia reduces the risks of postoperative thromboembolism in hip replacement surgery. The presence of varicose veins, being a non-smoker and having a low body mass index were associated with an increased incidence of deep vein thrombosis.

We aimed to find out whether the Hastings bipolar prosthesis moved in a bipolar fashion after its use for displaced fractures of the femoral neck. In 65 patients non-weight-bearing movement was assessed radiographically and compared with an earlier study of the Monk prosthesis. In 70% of patients, the only movement was between the acetabulum and the prosthetic shell, the prosthesis behaving as if it were unipolar. This did not change with time, but there was a slight improvement in the range of movement, particularly in flexion. The absence of movement between the outer shell and the metal head is most probably due to the design of the prosthesis and makes this prosthesis unsuitable for use in osteoarthritic hips.

We studied cartilage degeneration in 45 canine acetabula after implantation of prostheses with articulating surfaces of low-temperature isotropic (LTI) pyrolytic carbon, cobalt-chromium-molybdenum alloy and titanium alloy for periods ranging from two weeks to 18 months. Gross specimens and histological sections were compared with the nonoperated (control) acetabulum of the same animal. Cartilage articulating with LTI pyrolytic carbon exhibited significantly lower levels of gross wear, fibrillation, eburnation, glycosaminoglycan loss, and subchondral bone change than with metallic surfaces. Survivorship analysis showed a 92% probability of survival for cartilage articulating with LTI pyrolytic carbon at 18 months, as compared to only a 20% probability of survival for cartilage articulating with either of the metallic alloys.

Of 24 intertrochanteric osteotomies for avascular necrosis of the femoral head, 22 were followed up for an average of 63 months. Sixteen of the 22 cases had good or excellent results, including 5 of the 6 cases with Stage II disease and 11 of the 16 with Stage III changes. Success seemed to be inversely related to the size of the lesion. There were six major orthopaedic complications, but despite these we feel that the operation has a definite role in the treatment of the young active patient.

The occurrence of osteonecrosis following renal transplantation is well recognised but its pathogenesis remains unknown. We have quantified the number of empty osteocytic lacunae in the subchondral bone of femoral heads from a control group of patients, and compared these with femoral heads from a group of renal transplant recipients without evidence of overt osteonecrosis. There is a significant increase in empty osteocytic lacunae in renal transplant patients. We conclude that loss of osteocytes precedes other manifestations of osteonecrosis.

We reviewed the results of 14 total hip replacements in patients with juvenile chronic arthritis. The mean age at operation was 16 years (range 12 to 22 years); follow-up was from four to 11 years (mean 8.5 years). Postoperatively pain relief was sustained in all but one hip, while movement generally remained significantly restricted. No hip has as yet required a revision operation, although eight hips (57%) show radiological changes suggestive of impending failure. All patients had severe polyarticular involvement with associated restriction of locomotor activity. Potential causes contributing to loosening such as continuing diaphyseal bone growth and increased immunocompetence in adolescence are discussed.

In rabbits and goats, test implants with a porous surface of two layers of Tl-6A;-4V beads were examined at intervals for bond strength with bone. Half of the implants were coated with hydroxyapatite by plasma spray. The bonding strength with bone in the coated specimens was about four times greater than that of the uncoated specimens at two weeks, and twice as strong at six weeks. Twelve weeks after implantation, the strengths were similar. The hydroxyapatite coating of the beads provided earlier and stronger fixation.

A manufacturing technique to increase the bonding between bone cement and metal prostheses has been assessed in the laboratory by "push-out" tests, and the effects of contamination of the cement and of the prosthesis with blood and intramedullary contents have been studied. The technique, known as pre-coating, increases bond strength; this increase is preserved after contamination of the cement which does, however, cause some lowering of interface shear strength. The implications for clinical practice are discussed.

We have investigated the effect of joint tamponade and of traction in extension on the oxygen and carbon dioxide tensions in the femoral head of the immature goat, using mass spectrometry. Tamponade of 75 mmHg caused the oxygen tension in the femoral head to drop from 48 +/- 4 mmHg to 29 +/- 3 mmHg. Traction in extension further decreased the oxygen tension. Both these changes were highly significant. The partial pressure of carbon dioxide increased, but to a lesser extent and only effusion together with traction gave a statistically significant effect. Our study showed that joint effusion can produce hypoxia in the bone as a result of impaired blood flow to the femoral head. The application of traction increases this haemodynamic effect.

Three cases are reported which presented as "irritable" or "observation" hips and failed to respond to rest at home and in hospital. In each case a campylobacter organism was grown from the faeces; none were found in a group of 20 patients in the paediatric ward for other reasons. The patients responded to a course of erythromycin. It is postulated that they may have had a reactive arthropathy of the hip and suggested that cultures for Campylobacter be made as part of the investigation of irritable hip.

Perthes' disease is common in certain urban areas within Britain. It is one manifestation of a generalised growth disorder and nutritional causes are suspected. Orthopaedic surgeons throughout the Yorkshire region recorded all new patients with Perthes' disease over two years. There were large geographical differences in incidence which could not be explained by urban-rural or social class differences. No cases were recorded in a large area within the eastern part of the region, which is in high-grade farming land and has had a relatively low infant mortality throughout this century.

We describe three patients who developed gross calcaneus deformity following surgery for talipes equinovarus. One also had an associated valgus deformity and another had supination of the forefoot; all had intractable problems with footwear. Operation for transfer of the tibialis anterior to the heel, with correction of the associated deformities, was successful and improved both their gait and the shoe problems.

Anteversion of the femoral neck of 30 unpaired dry bones was measured directly, by ultrasound, and by computerised tomography. The angles measured directly corresponded well with the angles found by CT scan, but there was poor correlation between these and the angles measured by ultrasound. At present ultrasound seems to be unsuitable for the measurement of anteversion of the femoral neck.

We report two patients with permanent dislocation of the proximal tibiofibular joint and no history of trauma. Both needed operation, one for persistent pain and the other for common peroneal nerve involvement, and both had a good result.

Over a 25-year period, 12 patients had from 2.5 to 5.1 cm operative shortening of the tibia and fibula for leg length discrepancy at between four and 18 years of age. All recovered normal function and there was minor cosmetic impairment in only two cases. The only vascular complication was temporary delay in return of the circulation to the foot after tourniquet removal in one patient. The procedure is valuable for discrepancy of tibial length in patients when they present too late for epiphyseal arrest, when there is doubt as to the appropriate timing for epiphyseal arrest, or when it is uncertain at an earlier stage whether there is need for surgical correction.

We reviewed 47 patients with neurofibromatosis and dystrophic spinal deformities; 32 of these patients had been untreated for an average of 3.6 years and in them the natural history was studied. The commonest pattern of deformity at the time of presentation was a short angular thoracic scoliosis, but with progression the angle of kyphosis also increased. Deterioration during childhood was usual but its rate was variable. Severe dystrophic changes in the apical vertebrae and in particular anterior scalloping have a poor prognosis for deterioration. The dystrophic spinal deformity of neurofibromatosis requires early surgical stabilisation which should be by combined anterior and posterior fusion if there is an abnormal angle of kyphosis or severely dystrophic apical vertebrae. Some carefully selected patients can be treated by posterior fusion and instrumentation alone.

Ultrasound can be used to outline the spinous processes and the laminae, and thus to measure axial rotation. Using our own technique, we measured vertebral rotation in 47 patients with idiopathic scoliosis. There was a strong linear relationship between the Cobb angle and the rotation of the apical vertebra in untreated patients, but this relationship was lost in patients who had had brace treatment. Vertebral rotation can easily be measured by ultrasound. This is a harmless and fairly rapid investigation which can be used at routine follow-up examination of patients with idiopathic scoliosis.

We report two cases of Serratia marcescens infection at the sites of spinal fractures and emphasise the fact that neurological deterioration soon after spinal fracture may be due to acute vertebral osteomyelitis.

We have developed a simple technique for demonstrating the sagittal profile of each rotated level of a scoliotic spine and used it to determine the patterns of lordosis and kyphosis in each of six clinical types of idiopathic scoliosis. The currently accepted classification of scoliosis is inaccurate and a modification is proposed. The three main types of scoliosis were shown to have sagittal profiles distinctly different from each other and from normal. Single structural curves had short lordotic sections at their apices, limited above and below by kyphosis. Double curves showed longer lordotic sections limited only by one area of kyphosis. Lordosis throughout the thoracic and lumbar spine was associated with triple curve patterns. The biomechanical effects of the abnormal sagittal profiles provide a simple explanation for the genesis and progression of the different types of scoliosis, and the recognition of the pattern of the sagittal abnormalities permits treatment to be designed on a sound anatomical basis for individual cases.

We reviewed 20 adult patients with spondylolysis and isthmic spondylolisthesis an average of 10.5 years after treatment by anterior spinal fusion. Nineteen patients had excellent or satisfactory results. Ten of the patients were symptom-free at one year, and 15 were asymptomatic at final follow-up. Anterior spinal fusion can produce results comparable to those of posterior fusion with or without decompression. The results tend to improve with time in contrast to the known worsening of late results after posterior decompression without fusion.

We have reviewed seven patients who had triceps transfer after an old brachial plexus injury. All patients had a useful functional improvement with a good range of powerful elbow flexion; five patients could manage to bring their hand to their mouth. The basis of patient selection and the relative advantages of triceps transfer are discussed.

We aimed to determine the distribution of the ABO and Rh blood groups in 832 patients with a tendon rupture. Among these, the frequency of blood group O (52.8%) was significantly higher than in the general population of Hungary (31.1%) and the frequency of group A was significantly lower. Of the 83 cases of multiple ruptures or re-rupture, 57 patients (68.7%) had group O blood. The dominance of group O was found for all sites of tendon rupture, but there was no significant association with the Rh groups. Individuals with blood group O appear to have an increased risk of tendon rupture.

We compared retrospectively consecutive series of patients with cervical dislocation treated at two Australian centres. In Perth, 82 patients were treated by closed reduction and postural nursing. In Adelaide, 85 patients had closed reduction and early surgical stabilisation by interbody fusion. There were 46 bilateral dislocations, 101 unilateral dislocations, and 20 anterior subluxations. On admission 30 patients had complete tetraplegia, 17 incomplete tetraplegia, and 120 had minimal or no neurological loss. Our results indicated that closed manipulation under general anaesthesia is a safe and effective means of reduction in the acute stage. There was a high mortality rate for acute surgery in patients with complete tetraplegia. Early surgical stabilisation by dowel fusion reduced bed and hospital stay in patients with no neurological loss, but seemed to impair neurological recovery in patients with a neurological deficit on admission. Conservative management after reduction of bilateral dislocation or anterior subluxation led to a higher incidence of instability in patients with minimal or no neurological loss; in such cases surgery to stabilise the injured segment is indicated.

Neck injury of the whiplash type may lead to the cranial symptoms of the Barre-Lieou syndrome. Forty patients with this syndrome and 40 without it were investigated by a variety of imaging techniques. There was a clear correlation between root sleeve defects at C3/4 shown by special oblique myelographic views and cranial symptoms. Good results were obtained by anterior cervical discectomy and fusion at C3/4 in 21 cases. It is suggested that the syndrome may result from irritation of the sympathetic nervous supply at this level.

Unlike most other tumours, myeloma causes bone destruction without an osteoblastic reaction; we tried to assess whether myeloma secretes a humoral factor that inhibits osteoblasts. Human bone-derived cells were either co-cultured with myeloma cells, or cultured in medium conditioned by myeloma cells. Bone-derived cell growth was measured by cell counts and by uptake of tritiated thymidine (3H-Tdr); growth was inhibited when cultured in medium conditioned by myeloma cells and some inhibition was seen when the bone-derived cells were co-cultured with myeloma cells. The inhibiting effect was dose-dependent and also dependent upon the density of the myeloma cells conditioning the medium. The results of our study suggest that myeloma secretes an osteoblast inhibiting factor of less than 50,000 Dalton molecular weight.

Traumatic hemipelvectomy is rare, and is usually accompanied by injury to the genito-urinary tract and bowel. Recently, there have been an increasing number of reports of patients who have survived this injury, probably as a result of improved early care. We report three such cases and review the literature. The amputation wound should not be closed initially; early re-exploration to remove any dead tissue is indicated, and this should be repeated as necessary.

We assessed patellofemoral joint function by combining the measurement of maximal isometric extensor torque at the knee with clinical and radiological measurements in order to calculate the patellofemoral contact force. Eighteen volunteers established the normal ranges of results and the reliability of the system. Of the 39 patients with a variety of knee problems, 29 had anterior knee pain, and all had a subsequent arthroscopy. Patients with anterior knee pain and lesions in the patellar cartilage had significantly reduced isometric contact forces, but those with normal patellofemoral cartilage had normal contact forces. Our method may be useful in providing an objective assessment of anterior knee pain and a quantitative means of monitoring its treatment.

Seventy-six patients (83 ankles) with chronic lateral instability of the ankle were treated by a simple reconstructive operation, namely, a subperiosteal release on the distal part of the lateral malleolus. The released flap, including the insertion of both the anterior talofibular and the calcaneofibular ligaments, was reattached to the malleolus more proximally. Seventy-five patients (82 ankles) were examined at a mean of 24 months (range 12 to 70) after operation. In 78 ankles (95%) the result was excellent or good. Forty-four of the 51 patients (86%) whose sporting activities were restricted before operation had no restriction at follow-up. Recurrence of instability occurred in one ankle, following a further injury two years after operation.

A system for assessment of function after major pelvic injuries is proposed. This numerical system developed from a five-year prospective study of 60 patients. Five factors were assessed and scored: pain, standing, sitting, sexual intercourse and work performance. The total score then gave a clinical grade as excellent, good, fair or poor. The scoring system allows comparison between early and late results and also between various methods of treatment.

Eighty-two of 85 patients who had sustained a fracture of the waist of the scaphoid in 1985 were reviewed more than one year after injury. The incidence of nonunion, defined as a clear gap at the fracture site one year after injury, was 12.3%. This was much higher than expected. Most of the patients with nonunion had symptoms and had appreciable restriction of wrist movement. In a further 25% of the patients at review, the site of the fracture could be easily identified although it appeared to have healed. These patients were older and more of them were women. Three-quarters of these patients had symptoms but their wrist movement was essentially normal.

We report the technique and results of percutaneous cerclage used in treating 186 torsional fractures of the tibia, most of which were due to skiing accidents in young patients. It is recommended only for this type of fracture and has the advantages of simplicity, a low rate of complications and a relatively brief period in hospital.

We report a case of lethal air embolism during diagnostic arthroscopy using air to distend an acutely injured knee. Air had escaped from the joint through an intra-articular fracture and entered the venous system. During arthroscopy, pressure within the joint may be 5 to 10 times higher than venous pressure, so any medium may escape. We advise that the use of air, especially in freshly injured joints, should be abandoned in favour of saline or carbon dioxide.

An eight-year-old boy presented with massive pseudomalignant heterotopic ossification around the upper femur. The mass was completely excised because of severe pain, systemic illness and a flexion contracture at the hip. Symptomatic improvement was swift, but two weeks later the mass had recurred and was even more extensive. During the subsequent 18 months of conservative management he has been free of pain and there has been progressive resorption and remodelling of the heterotopic bone. There is now no limitation of physical activity and movement at the hip is full.