One hundred and fifty patients in Hong Kong with a diagnosis of tuberculosis of the thoracic, thoracolumbar or lumbar spine were allocated a random to the "Hong Kong" radical resection of the lesion and the insertion of autologous bone grafts (Rad. series) or to debridement of the spinal focus without bone grafting (Deb. series). All patients received daily chemotherapy with para-aminosalicylic acid (PAS) plus isoniazid for 18 months, with streptomycin for the first three months. After exclusions, the main analyses of this report concern 119 patients (58 Rad., 61 Deb.) followed up for 10 years. During the first five years the allocated regimen was modified because of the spinal lesion in 14 patients, but there were no further modifications between five and 10 years. No patient developed a sinus or clinically evident abscess or a neurological abnormality between five and 10 years. Bony fusion occurred earlier and in a higher proportion of patients in the Rad, series but at five and 10 years there was vary little difference between the series. Over the period of 10 years there was a mean increase in vertebral loss of 0.05 of a vertebral body in the Rad. series and 0.23 in the Deb. series. In both series most of this loss occurred in the first 18 months, with very little subsequent change in the next eight and a half years. Over the 10 years there was a mean reduction in the angle of kyphosis in the Rad. series of 1.4 degrees for patients with thoracic and thoracolumbar lesions and 0.5 degrees for those with lumbar lesions. By contrast, in the Deb. series there were mean increases in the angle of 9.8 degrees and 7.6 degrees respectively. In both series most of the changes had occurred early, and persisted subsequently. At 10 years 57 of 58 Rad. and all 61 Deb. patients had a favourable status, 50 (86 per cent) and 54 (89 per cent) respectively on the allocated regimen without modification.

A series of 75 patients who had undergone anterior cervical fusion between 1965 and 1977 were reviewed. The patients were divided into two groups: those in Group A had had the level of fusion indicated by cine radiography, whereas in Group B the level had been determined by plain radiographs and clinical symptoms and signs. Results showed that cine radiography was the more accurate diagnostic technique. Accurate diagnosis of the level to be fused, the careful clinical selection of patients and sound bony union were found to be vital to the success of anterior cervical fusion. The incidence of pseudarthrosis was significant in single-level fusions and was even greater in double-level fusions and in patients with a history of trauma, especially whiplash injuries. It was rare to develop recurrence of symptoms in adjacent levels after fusion of a level localised by cine radiography.

Acute myelopathy is a rare complication of Scheuermann's disease. Three patients are reported where spinal cord compression occurred at the apex of a kyphos. All were male, aged 14, 18 and 20 years, and each had a profound neurological defect associated with a short, sharp kyphos in the low thoracic region. Each patient underwent anterior decompression and all made an almost full recovery. It is deduced that factors which may influence the onset of cord compression include the angle of kyphosis, the number of segments involved, the rate of change of the angle, local anatomical variations, trauma, and possible secondary impairment of the vasculature of the cord.

Twenty-three adults with fractures of the odontoid process are reviewed. Te possible reasons for the high rate of non-union in reported series are considered: these include the type of fracture, its displacement, the presence of a gap at the fracture site, imperfect reduction and inadequate immobilisation. Type 2 fractures (at the base of the odontoid process) are the commonest and also the most liable to nonunion. In their treatment, reduction is important; as seen in the lateral radiograph at least two-thirds of the fracture surfaces should be in contact. Skull traction is not advised and halo-cast fixation is the treatment of choice; with this method 87.5 per cent of recent odontoid fractures united.

Thirty-seven patients treated for os odontoideum are reviewed. In 20 patients the treatment was conservative and in 17 consisted of occipitocervical or atlanto-axial fusion. Two patients died after the operation and another, who lived abroad, was lost to follow-up. The remaining 34 patients were followed up for an average of eight years: 19 improved, 14 were unchanged and one deteriorated. In the subgroup of 25 patients without cord signs, there were no significant differences between the two modes of treatment. Analysis of the radiological features of the upper cervical spine in 21 patients revealed a minimal sagittal diameter of less than 13 millimetres to be associated with a high risk of permanent cord damage. There was no correlation with the degree of instability per se. On the basis of this analysis, guidelines are suggested for the management of patients with an os odontoideum.

Three cases of spinal osteomyelitis due to brucellosis are reported, all in women. Radiological confirmation was delayed for at least three months after the first clinical manifestation, while in one patient a bone scan was positive at an early stage. In two of the three cases the diagnosis was delayed because of insufficient awareness of the disease. Spinal osteomyelitis caused by Brucella is indistinguishable radiologically from that caused by other micro-organisms and needle aspiration or exploration is frequently performed to establish the correct diagnosis. Increased awareness of brucellosis and the carrying out of appropriate blood cultures and serological tests may make these procedures unnecessary.

Seventeen patients with congenital spondylo-epiphysial dysplasia from six centres in Britain have been investigated and two variants delineated. There is wide clinical and radiological variability in each group with overlap between them, but 12 of the patients had very short stature and grossly disorganised hips with severe coxa vara, and the five remaining patients were less seriously affected with height only a little below the third percentile and only mild coxa vara. Both groups can be diagnosed at birth but the two cannot be differentiated on clinical and radiological grounds until after the age of three to four years when the developing severe coxa vara and difference in stature become apparent. All cases were sporadic with the exception of a concordant twin-pair.

Seventy-seven children admitted with a provisional diagnosis of acute osteomyelitis over a three year period have been reviewed. Acute haematogenous osteomyelitis was confirmed in 45 of these patients whose ages varied from three days to 14 years with a mean of 6.2 years. All patients were treated with intravenous fusidic acid and cloxacillin with splintage for three weeks followed by oral antibiotics for a further period of six weeks. Only seven patients required operation. One patient had recurrence of infection; all other patients were cured with no evidence of chronic osteomyelitis. It is suggested that surgical drainage of acute haematogenous osteomyelitis is seldom needed and that high intravenous doses of antibiotics in combination with splintage are adequate treatment in most cases.

A previously undescribed syndrome affecting the fingers of women is presented. The patients experience a sharp pain and then the fingers become blue and numb. The discoloration resolves within 72 hours without the changes normally associated with an ecchymosis. Clinical and haematological examination of six patients failed to show any common factors or associated systemic disease. This syndrome is of no clinical significance to the patient, but it is important for clinicians to be aware of it because the acute phase can cause anxiety, suggesting more serious vascular disease.

The release of gentamicin sulphate, sodium fusidate and diethanolamine fusidate from Palacos and CMW cements was studied using elution and serial plate transfer tests. Further tests were made to assay the drug remaining in the cement after antibacterial activity could no longer be detected by the above methods, to detect the sustained slow release of the residual drug, and to ascertain the mechanism of release. The results confirmed that the release of gentamicin sulphate could be detected for longer from Palacos cement than from CMW cement, but the opposite was true for sodium fusidate. Little difference was found in the case of diethanolamine fusidate. Comparison of elution and serial plate transfer tests, and of results of elution in buffers of different pH, demonstrated that the test method employed had a significant effect on the results, and the omission of details of methodology from some publications made comparison and evaluation of results difficult. Varying quantities of residual drug were found in cement from which antibacterial activity could no longer be demonstrated; further tests for sustained, slow release showed that the antibiotic did not remain fixed in the cement but was released at a rate too slow to be detected in the elution and serial plate transfer tests. It is concluded that antibiotics are released from the cement by a process of diffusion, but tests to determine the mechanism of diffusion were unhelpful. The theory of diffusion of drugs through solid matrices, and the clinical implications of the experimental findings, are discussed.

Twenty-six patients with rheumatoid arthritis who had undergone bilateral replacement of the hip and knee were reviewed at a mean follow-up time of 51.6 months. A further operation was necessary in five patients due to complications of replacement of the knee, and seven patients still had significant pain in at least one replaced joint. There were no cases of infection due to operation. Seventeen of the patients still used walking aids, but one-third of these did so because of pain in joints that had not been replaced. Patients preferred painless total replacement of the hip to that of the knee.

The measurements of the angle of anteversion of the femoral neck by ultrasound scanning is described. The method was compared with direct measurement in 30 dried femora, and was then used in 18 normal volunteers and eight patients. The method is non-invasive, accurate and easily applicable. Findings in normal subjects included variation of the angle of anteversion from 10 to 34 degrees with a maximal difference between sides of six degrees. The expected rotational deformity of the femur was found in patients with unilateral intoeing.

Thirty-five patients were treated for Type III fractures of the intercondylar eminence of the tibia and were followed up for two to seven years. There were 20 Type IIIA fractures and 15 Type IIIB fractures. The avulsed fragment was reduced by operative arthroscopy and maintained either by extension and immobilisation in a cast or by crossed percutaneous pin fixation. Involvement of the medial collateral ligament or lateral meniscus was confirmed by valgus stress radiographs and by arthroscopy. Primary surgical repair through a separate incision was required in a significant number of patients. At follow-up, few patients suffered ligamentous instability, lack of extension, atrophy of the quadriceps, pain or effusion, and symptoms were minimal. Patients requiring surgical repairs of collateral ligaments or of peripheral detachments of the meniscus generally required a longer period of rehabilitation. Arthroscopic reduction and percutaneous pin fixation provided an effective treatment and significantly decreased the time spent in hospital and the morbidity experienced after alternative treatments.

The role of arthroscopic meniscectomy in middle-aged patients has not previously been evaluated. This paper reports on 73 knees in 68 patients aged over 40, all of whom were shown arthroscopically to have meniscal tears and who were felt to be suitable candidates for meniscectomy. Many of these patients had typical traumatic meniscal tears, and if no degenerative joint changes were present at the time of meniscectomy, 95 per cent of them had good or excellent results an average of two and a half years later. In those instances where degenerative joint changes were present, removal of the offending segment of torn meniscus produced 80 per cent good or excellent results over the same period of time. These facts seem important now that arthroscopy permits such precise diagnosis of meniscal tears and of joint degeneration.

A prospective study was made of 100 knees which had been operated on for various kinds of internal derangement. An observer, who did not know the clinical condition of the knee, recorded whether or not there were articular lesions of the femoral condyles. Lesions were found to be localised to a triangular area on the medial condyle and to a strip on the lateral condyle. Similar lesions have been described in association with flexion deformities in rheumatoid and osteoarthritic knees. Lesions were found in 49 out of 50 knees which had been locked for more than three days. They were also found in 29 knees in which there appeared to be full extension before operation, but where there was either a torn meniscus with a history of intermittent locking or serious anterolateral instability. In these cases it was considered that the final "screw-home" mechanism of full extension had been lost. Lesions were not present in 10 knees which appeared locked, but in nine of these the interval between injury and operation was less than three days. Lesions were not found in eight knees where there was full extension and no history of locking or instability. In four knees with a plica syndrome similar lesions were present.

The occurrence of a radiolucent line at the interface of bone and cement in total joint prostheses is a frequently observed, although little understood, phenomenon. Because of an operative technique utilised in instances of bone loss, we have, within a single implant mass used in each of a series of 18 total knee replacements, been able to observe two separate interfaces, one between bone and cement and the other between bone and cobalt chrome. The average period of observation was 32 months. All of the knees except one demonstrated a lucency at the bone-cement interface; only one of the knees had a similar lucency at the bone-CoCr interface. One of the knees was studied histologically. In the light of the universal observation of macrophages at bone-cement interfaces and the recent finding that osteoclasts are derived from macrophages, these observations are significant in relation to the aetiology of bone-cement lucencies.

Thirty-five cases of osteochondritis dissecans of the talus, operated on between 1950 and 1978, were studied. Twenty-four were available for follow-up an average of 47 months later. Three standard surgical approaches were used, and the osteochondritic fragment removed. In some cases the base of the defect was drilled. Good results were obtained in 15 patients, and fair in nine. There were no poor results. It was concluded that the defect is caused by trauma; that early operation gives the best results, 12 months being the critical delay time; that drilling the base of the defect improves results; and that the sex of the patient and the location of lesion are of little significance.

The effect of calcaneal traction on the compartmental pressure in the legs of five individuals with tibial fractures was studied. Mean resting pressures without traction were found to be 31.9 mmHg for the deep posterior compartment and 27.0 mmHg for the anterior compartment. For each kilogram weight of traction applied the deep posterior pressure rose by 5.7 per cent of the resting value and the anterior pressure by 1.6 per cent. It is suggested that the weight of traction should be only sufficient to render the patient comfortable and maintain alignment of the limb. Excessive traction is likely to increase the risk of compartmental ischaemia. The application of six kilograms of traction would raise the mean resting pressure by 34 per cent from 31.9 to 42.7 mmHg.

Although a variety of techniques have been used with varying success to induce scoliosis in animals, primates have rarely been used. A series of monkeys is presented where scoliosis developed incidentally during the routine virulence testing of live, attenuated, oral poliomyelitis vaccines by intraspinal injection. The site and extent of histological damage in the different anatomical areas of the spinal cord were examined in 25 scoliotic monkeys and 25 matched controls. Analysis of the data demonstrated that there was significantly greater damage on the convex side of the spinal cords of the scoliotic animals, particularly in the sensory areas-the posterior horn and Clarke's column. Scoliosis was not thought to be caused by clinical poliomyelitis as the involvement of the anterior horn was not significantly greater than in the scoliotic animals than in the controls. These observations are taken to support the view that scoliosis may develop as a result of asymmetrical weakness of the paraspinal muscles due to the loss of proprioceptive innervation.