Dislocation is the most frequent serious complication following total hip replacement for subcapital femoral fracture. We report a prospective study, using matched groups, which compared the range of hip movement following hip replacement for arthritis and for fracture. The range of movement was significantly greater in the fracture group. We suggest that this is a predisposing factor for dislocation.

Fractures of the femoral shaft are generally considered to affect young patients, but we have reviewed 24 cases in patients over 60 years who have been treated by locked nailing, usually by closed methods. Most were women with low-velocity injuries, but despite this, 14 fractures were significantly comminuted. The complication rate was 54% with a peri-operative mortality of 17%. Most complications were the general ones of operating on elderly patients. Specific complications included: fractures below an abnormal hip, proximal fracture related to the nail and poor purchase in the distal femur. In all survivors, the femoral shaft fractures united satisfactorily, and the fixation allowed early mobilisation. The locking nail appears to be an effective method of managing femoral shaft fractures in the elderly patient.

Magnetic resonance imaging (MRI) was used to compare the appearance of the spine in 20 adolescents with proven symptomatic intervertebral disc herniations with that in 20 asymptomatic patients who acted as controls. Abnormality in the signal from the nucleus pulposus of one or more discs was present in all patients, while only four of the 20 controls had any abnormal signals. In all the patients the symptomatic disc produced an abnormal signal and in most a herniated fragment of the nucleus pulposus was identified. Fifteen of the 20 patients had multiple-disc abnormality: six had three abnormal discs and nine had two. This suggests there was an underlying diathesis in patients who later developed disc herniation.

The role of antibiotics in the treatment of disc-space infection is controversial. This study assessed the tissue penetration of flucloxacillin and cephradine into the normal intervertebral disc after intravenous administration of a bolus dose of antibiotic. Twenty-five discs were removed from 12 adolescent patients having anterior spinal surgery to correct scoliosis; antibiotic had been administered between 30 minutes and four hours before operation. Despite high blood levels, no antibiotic could be detected by bioassay or by high-pressure liquid chromatography (h.p.l.c.) in any of the specimens from the nucleus pulposus or the annulus fibrosus.

Magnetic resonance imaging (MRI) of the spine produces images which reflect the chemical composition of the intervertebral disc. We have conducted a prospective study of the serial changes in the MRI appearance of the intervertebral disc after chemonucleolysis with the enzyme chymopapain. Fourteen patients were studied after single-level chemonucleolysis and the results compared with a control group of 17 discs in six patients who had diagnostic discography without enzyme insertion. A consistent pattern of gradual loss of signal from the nucleus pulposus culminating in complete loss of nuclear signal was seen in all cases after chemonucleolysis. Chymopapain therefore produced MRI changes analogous with premature gross disc degeneration. The rate at which this occurred varied; complete loss of signal took at least six weeks. Transitory minor end-plate changes were present in five patients, probably representing a mild chemical discitis. No similar changes were seen in the discography group.

The lumbar spines of 22 patients were examined for disc degeneration by magnetic resonance imaging (MRI) and by discography. The results from 50 intervertebral discs visualised by both techniques were independently assessed and graded on a five-point scale from normality to gross degeneration and then compared. In 44 discs the results agreed. Of the six discs which gave differing results, four discrepancies were due to observer error and two to incorrect placement of the discographic needle. MRI was shown to be more accurate than discography in the diagnosis of disc degeneration. It has several major advantages, which should make it the investigation of choice.

Weakness of dorsiflexion of the foot is a common complication of proximal tibial osteotomy and it has been suggested that this may be caused by an anterior tibial compartment syndrome. A prospective study of 20 patients undergoing tibial osteotomy was undertaken, in which compartment pressures were recorded and related to clinical signs. In 10 of the patients, the operation site was drained, and in 10 no drainage was employed. The undrained group showed significant elevation (greater than 45 mmHg) of the anterior compartment pressure in seven patients, and five of these had transient clinical signs. Only one patient had any permanent deficit, a minor asymptomatic weakness of extensor hallucis longus. In the drained group the pressures remained below 30 mmHg in all except two patients, who both had only a minor pressure rise and no significant early clinical signs. However, two patients from this group later developed weakness of dorsiflexion, probably due to common peroneal nerve injury, the cause of which is not clear.