Intervertebral disc cells exsist in a precarious nutritional environment. Local concentrations depend on both nutritional supply and demand. Little is known about the metabolism of disc cells; existing data focuses on intact tissue, where the local metabolic environment is unknown. We have thus developed a closed chamber to study the metabolism of isolated cells under controlled conditions.

Bovine disc cells were isolated from coccygeal discs and transferred to the sealed chamber, in which embedded electrodes measured pH, pO2 and glucose concentration, and a port allowed sampling and addition of metabolic reagents. Metabolic rates were assessed from concentration changes. Cell viability was assessed and intracellular ATP measured at completion of each experiment.

Under standard conditions, metabolic rates were similar to those measured in tissue, with a glucose:lactic acid ratio of approximately one to two. We have also examined the effect of extracellular pH on nucleus pulposus cell metabolism. Between pH 7.4–6.8, metabolism is insensitive to extracellular pH, and lactic acid production agrees with the literature 1, 2. Below pH 6.8, lactic acid production fell linearly with decreased pH. At pH 6.4, lactic acid production had fallen by 60%, and intracellular ATP by 80%.

These results show a fall in lactic acid production with extracellular acidification, which in vivo arises mainly from lactic acid produced by the cells. This may be protective. However the decrease in metabolism, and hence loss of ATP, may have a detrimental effect on the cells. There is thus a complex interplay between different components of the nutritional environment. Investigating these in combination should give valuable information about disc cell metabolism, as changes in cells metabolism can affect nutrient availability and hence cellular activity and viability.

Scoliosis is a disease characterised by vertebral rotation, lateral curvature and changes in sagittal profile. The role of mechanical forces in producing this deformity is not clear. It is thought that abnormal loading deforms the disc, which becomes permanently wedged. Modelling and in vitro studies suggest that such deformations should increase intradiscal pressure. Intradiscal pressure has been measured previously in a variety of clinical environments. The aim of this study is to measure pressure profiles across scoliotic discs to provide further information on the role of mechanical forces in scoliosis.

Pressure readings were obtained in consented patients with ethical approval using a needle-mounted sterilised pressure transducer (Gaeltec, Dunvegan, Isle of Skye) calibrated as described previously. The transducer needle was introduced into the disc of an anaesthetised patient during routine anterior scoliosis surgery and pressure profiles measured. Signals were collected, amplified and analysed using Power-lab and a laptop computer.

Pressure profiles across 10 human scoliotic discs from 3 patients have been measured to date. Pressures varied from 0.1 to 1.2 MPa.

Annular pressures showed high pressure, non-isotropic regions on the concave but not convex side of these discs.

Nuclear pressures recorded from the discs of these scoliotic patients were higher than those recorded previously in non-scoliotic recumbent individuals.

One of the mechanisms which controls bone growth, repair remodeling and absorption is mechanical loading. There exists no long-term in vitro model to study bone cells together with their matrix, nor a model that can apply quantitative mechanical forces of physiological amplitudes and frequencies. The analysis of the mechanical properties of bone (Young’s modulus and visco-elastic moduli) on small pieces of bone is also difficult with present devices. We have built a device that can maintain full viability and physiological response of bone for a period of several weeks and integrates all three functions.

10mm diameter bone cores 5 mm thick were obtained from the trabecular bone of the distal ulna of a 24 months old cow by precision cutting with diamond saws and keyhole cutters (our pattern) in sterile 7–10°C phosphate buffered saline (PBS) and cultured in a variation of DMEM containing fructose HI GEM.

Results: The results of these studies have shown that perfusion of trabecular bone can maintain all cells and maintain bone structure for at least 72 days. In conventional methods for bone organ cultures, small bones, such as rat calvaria, quickly start to resorb bone and degenerate. In our perfusion system we see no evidence of change.. Initial experiments have indicated that there are 2 visco-elastic moduli of bone with different time constants, that the elastic modulus of trabecular bone varies is site dependant and that loading to 0.4% compression raises prostaglandin E2 and insulin-like growth factor 1 within a few hours. Mechanical stiffness of bone is increased by 35% when loaded for 20 days at 4,000μ, and decreases by 25% when not loaded. PTH at 10-10M increases stiffness over the load effect and 10-6M PTH decreases stiffness even in the presence of loading. Active osteoclasts are seen during the whole culture period indicating that the stem cells are present and functional.

We gratefully acknowledge support by the German Arthrose Foundation (DAH) and the AO in Davos, CH.

Discitis is uncommon in children and presents in different ways at different ages. It is most difficult to diagnose in the uncommunicative toddler of one to three years of age. We present 11 consecutive cases. The non-specific clinical features included refusal to walk (63%), back pain (27%), inability to flex the lower back (50%) and a loss of lumbar lordosis (40%). Laboratory tests were unhelpful and cultures of blood and disc tissue were negative.

MRI reduces the diagnostic delay and may help to avoid the requirement for a biopsy. In 75% of cases it demonstrated a paravertebral inflammatory mass, which helped to determine the duration of the oral therapy given after initial intravenous antibiotics.

At a mean follow-up of 21 months (10 to 40), all the spines were mobile and the patients free from pain. Radiological fusion occurred in 20% and was predictable after two years. At follow-up, MRI showed variable appearances: changes in the vertebral body usually resolved at 24 months and recovery of the disc was seen after 34 months.

Transverse fractures of the sacrum with neurological complications have been studied in four patients illustrating the following features: diagnosis is often delayed, there are radiological difficulties in making the diagnosis, and the indications for surgery are not well defined. Specific radiographic views are recommended. All the cases presented in this report responded well to conservative management.

Ten normal neonatal hips were examined in stillborn babies. At first, forcible Barlow manoeuvres did not produce subluxation or dislocation, but by repeated examination a previously stable joint could be rendered unstable. Dissection of the hips showed that the vacuum fit between the femur and the acetabulum was an important factor in neonatal hip stability. The posterior capsule was not a strong or, in itself, an important structure. It is postulated that the capsule and the labrum act together as 'O' rings to maintain the vacuum fit; it is possible that repeated examinations, by producing an effusion, could break the seal and allow instability.

We describe a simple, quick ultrasound screening test for CDH, and its use in a prospective study of babies with a 'high risk' factor, over one year from January 1987. From a birth population of 3,879, 812 hip scans were performed on 406 babies and 98 babies were abnormal. So far, there have been no late cases of CDH. Family history, breech malposition, and postural foot deformities were confirmed to be important risk factors, but babies with a simple click were equally at risk. Our early results indicate that a large proportion of the potential late cases are contained within our extended high-risk group.

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.

Patients with myelomeningocele who had had surgery to stabilise the hip were reviewed; the results of the 106 operations in 88 patients were assessed. In the earlier part of the series there were 55 children who had 64 iliopsoas transfers; later in the series 33 children had 42 varus-rotation osteotomies combined with adductor tenotomy, anterior obturator neurectomy and psoas division. The technical results of both operations were satisfactory: following iliopsoas transfer only 19% of the hips were either dislocated or subluxated; the corresponding figure for the osteotomy was 12%. Thus varus-rotation osteotomy with psoas division, adductor tenotomy and anterior obturator neurectomy was at least as effective in stabilising the hip as iliopsoas transfer. Nevertheless 80% of the latter and 61% of the osteotomy patients relied on wheelchairs for mobility.

In a prospective, controlled study 58 patients aged under 60 years with Colles' fractures were treated either by a forearm plaster or by the application of an external fixator. In 94% of those treated by a fixator it was possible to insert the distal pins of the frame into the fracture fragment, the fixation obtained being sufficient to forgo additional splintage. The external fixator proved more effective at holding the manipulated position, and the radiological loss of position during fracture union was minimal compared with that seen in patients treated in plaster.

In a randomised prospective trial 98 elderly women with trochanteric fractures of the femur were treated with either a 135 degrees Jewett nail-plate or a 135 degrees Dynamic hip screw. The results at six weeks, three months and six months were statistically analysed. There were no significant differences in the two groups with regard to pain, length of hospital stay, morbidity or mortality. Although operative difficulties and open reduction were more common with the Dynamic hip screw, at the end of six months more patients in this group were mobile and there was significant radiological evidence of better compression without loss of fixation.

Partridge bands have been developed and marketed on the assumption that their ribbed under-surface would ensure less interference with periosteal and cortical blood flow than other cerclage systems. Three cases are reported of serious clinical complications from loss of cortical bone under the band, and interference with the external bridging callus response.

Twenty-one patients with leg-length inequality underwent femoral lengthening using the Wagner technique. When reviewed, seven were found to have varying degrees of posterior subluxation of the knee. Critical assessment demonstrated that each of these was associated with a hypoplastic femur. It is postulated that posterior displacement of the tibia on the femur occurred as a result of the distal femoral and intraarticular bony deficiencies.

The diagnosis of acute osteomyelitis is often very difficult during the first 24 to 48 hours. Bone scanning has been a useful adjunct in this diagnosis by demonstrating increased uptake in the area or areas of involvement. Occasionally the pathological area is "cold" on scanning, which may lead to a misdiagnosis. This paper presents three cases demonstrating this unusual finding.