Rigid posterior fixation of the skull to the third, fourth and fifth cervical vertebrae was achieved in three patients who, as a result of operation, had gross instability of the craniocervical junction. An anatomically contoured steel loop was secured to the occiput via small burr holes and to the vertebrae by sublaminar wiring. This technique has the advantage over bone grafting, either alone or with cement, in that it affords rigid stabilisation, allows early mobilisation and may contribute to eventual bony fusion.

Twelve cases of sternal injury associated with spinal fractures have been reviewed. The sternum is regularly buckled or fractured in patients with high thoracic spinal fractures. Our review suggests that sternal injuries may also be associated with spinal fractures outside this region, and with types of fracture other than crushing of vertebral bodies. Injury to the sternum, when due to indirect violence, is almost always associated with a severe spinal column injury. A displaced fracture of the thoracic spine, with or without an associated sternal fracture, can produce significant widening of the mediastinal shadow on a chest radiograph. This is caused by a paravertebral haematoma, and can be difficult to differentiate from widening due to an aortic rupture.

We report three patients in whom a fractured odontoid process was associated with a fracture of the superior articular process of the second cervical vertebra. Although there were no signs of neurological disorder, damage to the C1-C2 joint in all three patients made fusion necessary. Forced lateral flexion is suggested as the possible mechanism of injury.

A method of stabilising spondylolisthesis using Dwyer instrumentation is described and the results in seven patients are presented. The operation is straightforward, has few complications and also succeeds in reducing the angle of slip.

The results of surgery in 59 patients with Scheuermann's kyphosis are reported at an average follow-up of 56 months. These show that in skeletally immature patients, in whom the iliac apophysis has not yet fused to the body of the ilium, posterior fusion alone is adequate and is followed by little loss of correction. For skeletally mature patients combined anterior and posterior surgery is recommended. In all cases a period of pre-operative treatment is important. It is stressed that the indications for surgery are limited.

The term "congenital scoliosis" contributes little to our understanding of aetiology, for "congenital" simply means "to be born with" and is applicable to deformities present at birth whether these are genetically determined or acquired in utero. The presentation of monozygotic twins, one of whom has congenital scoliosis (vertebral anomalies) while the other is normal, provides a rare opportunity to study the cause of this deformity. Three pairs of monozygotic twins, previously unreported, are presented with a review of the previous literature. These cases add weight to the argument that congenital scoliosis may be acquired in utero rather than being genetically determined.

The development of the iliolumbar ligament and its anatomy and histology were studied in cadavers from the newborn to the ninth decade. The structure was entirely muscular in the newborn and became ligamentous only from the second decade, being formed by metaplasia from fibres of the quadratus lumborum muscle. By the third decade, the definitive ligament was well formed; degenerative changes were noted in older specimens. The iliolumbar ligament may have an important role in maintaining lumbosacral stability in patients with lumbar disc degeneration, degenerative spondylolisthesis and pelvic obliquity secondary to neuromuscular scoliosis.

Arthroscopic surgery of the shoulder was performed on 439 patients over a 10-year period: these patients are reviewed after a minimum follow-up of one year. Diagnostic arthroscopy is known to be valuable and we have found that arthroscopic surgery also is safe and effective. It was useful in treating frozen shoulder, early osteoarthritis, isolated tears of the glenoid labrum and lesions of the biceps tendon. It was less useful in treating partial tears of the rotator cuff, tendonitis and severe osteoarthritis, and of little value in treating complete tears of the rotator cuff or in treating patients in whom previous operations on the rotator cuff had failed. It may prove to be a useful method of performing synovectomy in rheumatoid arthritis and of treating instability.

Techniques are described by which metal implants can be designed and produced to fit precisely a bony site at a subsequent operation. CT scans and solid modelling were used to produce an accurate three-dimensional representation of the surface of the bone. These techniques were applied to the production of an internal fixation device for shoulder arthrodesis after the resection of a neoplasm of the proximal humerus. The reconstruction utilised a free vascularised fibular graft between the scapula and the distal humeral remnant, fixation being secured with the custom-made implant.

One hundred and nine children with myelodysplasia were evaluated and classified according to the level and type of paralysis and its effect on functional ability. Thirty-one per cent of the patients were paralysed at the thoracic level, 26% at the upper lumbar level, 30% at the lower lumbar level and 13% at the sacral level. Fifty-four per cent of these patients demonstrated the classic flaccid paralysis in the lower limbs with normal upper limbs; 9% were flaccid in the lower limbs, but were spastic in the upper; 24% were spastic in the lower limbs; 13% were spastic in the upper and lower limbs. Patients with spastic lower limbs required more orthopaedic procedures, more days in hospital and in casts, and were less likely to walk than those with flaccid paralysis. Patients with spastic upper limbs were less likely to be independent in activities of daily living and were more likely to require special schools than patients with normal upper limbs. In addition to the spinal cord level of the lesion, the degree of spasticity is important in the evaluation, treatment and prognosis of myelodysplastic patients.

The results of 75 total hip replacements in 42 children with juvenile chronic arthritis are reported after a mean follow-up of 5.4 years. Their ages ranged from 11 to nearly 17 years at operation and many had active disease. Severe pain and marked stiffness of the hips were limiting their independence. At least half of the children were still growing and continued to grow after operation. The patients were carefully selected and gratifying results were obtained, but pre-operative assessment and overall supervision by a rheumatologist are important. Technical difficulties related to the size and maldevelopment of the hip are discussed. There was no infection and the single case of loosening of a femoral component after nine years has been successfully revised.

We report 60 synovectomies of the knee in 51 children with juvenile chronic arthritis. Synovitis had been present for an average of 5 years and the average age at operation was 13 years. Results were evaluated in terms of pain, knee movement, relapse of synovitis and radiological change during a follow-up averaging 7.5 years. The relief of pain was rewarding and there was a slight postoperative gain in range of knee movement in most cases. The older the patient at onset of disease, the greater the risk of pain during follow-up. Progressive joint destruction was more common in younger patients, those with systemic or polyarticular disease, and those with highly active disease at the time of operation. Recurrence of synovitis was more frequent in patients who had their operation in a phase of high disease activity; this occurred most often in patients with polyarticular disease.

Closed rupture of the middle slip of the extensor hood of a finger is easily missed until the late appearance of a buttonhole deformity. Early diagnosis gives the best chance of satisfactory treatment, but Boyes' test becomes positive only at a late stage. A new test is described in which, from a 90 degree flexed position over the edge of a table, the patient tries to extend the proximal interphalangeal joint of the involved finger against resistance. The absence of extension force at the proximal joint and fixed extension at the distal joint are immediate signs of complete rupture of the central slip. The theoretical basis and the method of performing the test are discussed.

The value of remanipulating a Colles' fracture which has redisplaced after primary reduction was assessed in 50 patients. In those over 60 years old, remanipulation failed to achieve a lasting improvement in position, while the majority of those under 60 years maintained a significant improvement in dorsal angulation. It is concluded that the elderly patient does not benefit from this procedure.

The cavities left after resection of bone bridges for partial closure of growth plates in children have commonly been filled with free fat grafts. Such cavities have been seen to elongate and thus enlarge during growth after the operation, but the fate of the grafts has been unknown. Similar cavities, made in the tibiae of growing pigs were filled with autogenous fat and studied by radiography for periods of up to 9 1/2 months. These cavities elongated in a manner similar to those in the clinical cases, and histological section showed them to be filled with living adipose tissue. The volume of this tissue had continuously increased in parallel with the growth in length of the bone. The fate of the grafts used in children may be similar to that seen experimentally.

Fifty-six patients with ununited intracapsular fractures of the femoral neck were treated by internal fixation and muscle-pedicle bone grafting. All had some absorption of the femoral neck, and many had avascular necrosis of the femoral head. At operation the sclerosed surfaces of the fractures were freshened, the avascular femoral head was decompressed and the muscle-pedicle graft was fixed with silk thread wrapped around pins. Satisfactory union occurred in 42 patients (75%), and delayed union in seven, of whom four (7%) eventually united without further treatment and three united after osteotomy. Non-union occurred in five patients and technical failure in two.

External fixation of fractures of the leg may give uneven results and a high rate of complications. We postulate that three basic principles can govern the optimal use of these devices. The external fixation frame should avoid damage to vital anatomical structures, it should allow access to the injured area and it should meet the mechanical demands of the patient and the injury. From 1978 to 1981 these principles were evaluated prospectively in 75 consecutive cases of complex tibial injury treated with an external frame. Most were open fractures. The study confirmed that the principles were safe and effective; they have general application and do not depend on the use of a particular frame or device. By following them we have eliminated the majority of complications seen after traditional methods of external fixation.

Of 135 consecutive patients admitted with subtrochanteric fractures of the femur, 104 were studied; half had internal fixation with a Zickel nail and half had a nail-plate device. Fractures treated with a Zickel nail had significantly less blood loss during operation and took less time to walk with full weight-bearing, but the incidence of technical error at operation was higher. Errors included malalignment of the cross-pin, penetration of the femoral cortex and comminution of the greater trochanter. There was mechanical failure within one year of surgery in 17% of the nail-plate series but no implant failures in the Zickel nail group within the same period. The total time spent in hospital was similar in both groups. The Zickel nail provides better fixation for subtrochanteric fractures than a simple nail-plate but, because of technical difficulty, its use should be reserved for surgeons of reasonable experience.

The results of triple arthrodesis performed in 80 feet and followed for an average of 13 years are reviewed. Although the majority of patients were very pleased, the results of objective assessment were less favourable. There was a high incidence of degenerative joint changes in the ankle and midfoot and also of pseudarthrosis, avascular necrosis of the talus and residual deformity. Pre-operative rigid equinovarus deformity produced the majority of the poor results. It is suggested that bony resection alone might not be the best means of correcting severe equinus.

We report the results of a simple technique of ankle arthrodesis which is, however, indicated only when the foot can be reduced manually to a functional position. A special milling-cutter with an expulsion piston is used to obtain a cylindrical bone graft which is reintroduced having been reversed from left to right and rotated through 90 degrees. The operation is simple and very rapid. It has been performed on 72 patients, 62 of whom have been followed up for an average of six years. Fifty-seven were painless with bony fusion in a functional position; one was solid and painless but in valgus. In only four patients were the results unsatisfactory.

The acute childhood diseases haematogenous staphylococcal osteomyelitis and septic arthritis were studied concurrently using avian models which closely resemble the human diseases. Ultrastructural studies during the initial stages of bone and joint infection showed that adherence of bacteria to cartilage, bacterial proliferation, cartilage destruction and subsequent bacterial spread along the vascular channels within cartilage were common to both disease processes. Histological studies revealed that transphyseal blood vessels were present in the growing chickens and were a likely explanation for the frequency of the concurrence of acute osteomyelitis and adjacent joint infection following intravenous injection of bacteria. Transphyseal vessels provide a direct connection between the growth plate (physis) and epiphyseal cartilage supplying a route for bacteria to spread from an osteomyelitic focus in the metaphysis to the epiphysis and subsequently to the joint lumen.

The Denis Browne abduction harness was used in the management of 127 abnormal hips in 104 children at Queen Mary's Hospital for Children from 1966 to 1980, both as the initial treatment for unstable hips recognised soon after birth, and for children presenting later and whose hips first required reduction by gradual abduction in traction. The incidence of significant avascular necrosis was 3.1%, and occurred only in the primary treatment group, emphasising again the need for gentle care of infant hips. There have been no other significant complications and the appliance has functioned well.

We studied the mechanical and biochemical properties of articular cartilage from 22 osteoarthritic femoral heads obtained at operation and 97 femoral heads obtained at autopsy. Cartilage from the zenith and from the antero-inferior aspect of each head was tested both in tension and in compression. Water content, swelling ability and proteoglycan content were measured, the cartilage was examined histologically and the density of the underlying bone was assessed. Fifty-five of the autopsy specimens were defined as macroscopically normal because they exhibited no progressive fibrillation patterns on staining with Indian ink; but significant changes in water content, bone density and tensile strength related to age were seen in this group. In 20 pairs of femoral heads which were both macroscopically normal, we found, surprisingly, that cartilage from the left and right sides of the same patient was sometimes very different. Compared with the normal autopsy specimens the osteoarthritic specimens had a significantly increased swelling ability, a lower proteoglycan content and impaired mechanical properties, being both weaker in tension and softer in compression. Abnormal autopsy specimens had values intermediate between those of osteoarthritic and normal groups. Results from this abnormal group suggest that there is no primary loss of proteoglycan in early osteoarthritis.

In order to define the predisposing factors and outcome of infected arthroplasty of the knee, a retrospective analysis of a consecutive series of 471 knee arthroplasties was performed. There were 23 cases of superficial wound infection and 25 of deep infection. Superficial wound infection alone resulted in a painfree gait, with little limitation of movement. Rheumatoid arthritis, the use of constrained prostheses and the presence of a superficial wound infection, all predisposed to deep infection. Deep infection was eradicated by long-term antibiotics in only two patients in whom skin cover was successfully provided by a gastrocnemius musculocutaneous flap. Excision of a sinus track, wound debridement and exchange arthroplasty were universally unsuccessful. Arthrodesis, however, in 11 out of 12 cases, provided the painfree gait these patients desire.

A new method of demonstrating sagittal laxity in the anterior cruciate-deficient knee is described. Seventy such knees were compared to 70 normal knees. Sagittal laxity was recorded as the average displacement of the medial and lateral femoral condyles. This displacement index was significantly different between the two groups of knees (P less than 0.0001). A range for normal and abnormal knees is discussed. Quantitative assessment of the degree of sagittal laxity by clinical evaluation is shown to be unreliable. Only the pivot-shift test demonstrated any significant correlation with the amount of sagittal displacement (P less than 0.05).

Minor degrees of malalignment of the patella and anatomical abnormalities including a flattened sulcus angle and an increased ratio between patellar tendon length and patellar length (PT:P) have been suggested as predisposing factors in the causation of chondromalacia patellae, as well as patellar instability. In order to confirm or refute this hypothesis a prospective study has been performed comparing the congruence and sulcus angles and the PT:P ratio in a group of 35 patients with chondromalacia confirmed by arthroscopy and a group of 33 patients with instability, with those of a group of 50 knees in normal volunteers. While there was a statistically significant correlation between an increased sulcus and congruence angle and a high-riding patella in patients with instability, no correlation could be identified in patients with idiopathic chondromalacia.

We reviewed 230 patients an average of 34 months after they had undergone partial or total meniscectomy by surgeons of different experience in a busy unit. Open and arthroscopic meniscectomies were compared. Arthroscopic partial meniscectomy resulted in a significant reduction of inpatient stay and earlier return to work and sport. Analysis of the type of meniscal damage showed that arthroscopic removal of "bucket handles" achieved better results than open techniques. Comparatively poor results were found for lateral meniscectomy.

Hyperphosphatasia, or hereditary bone dysplasia with hyperphosphatasaemia, is a rare genetic disorder which is characterised by failure to transform woven into lamellar bone. Clinical, radiological and histological features establish the diagnosis, fractures, deformities, diffuse sclerosis on radiographs and high serum alkaline phosphatase being characteristic. We report the case of a 27-year-old man with follow-up at the same hospital for 20 years. Attempts at treatment with calcitonin and disocium etidronate (EHDP) failed, but stapling of the growth plates at the knee was successfully performed. Transverse "brittle" fractures of the humerus, lower leg and ribs healed normally, but internal fixation and late bone grafting were required for a subtrochanteric stress fracture of the femur at the age of 24 years. At present the patient has no clinical problems and leads a normal life.

Tricho-rhino-phalangeal syndrome is probably not so much uncommon as unrecognised. Its significance to orthopaedic surgeons, apart from the functionally unimportant minor finger deformities, lies in its mimicking both Perthes' disease and diaphyseal aclasis. The 14 cases analysed in this paper illustrate the wide range of clinical variation.

Three cases are reported in which an osteosarcoma developed in relation to an enchondroma in a long bone. Two of the cases were in the proximal femur whilst one occurred in the proximal humerus, both recognised sites for old calcified enchondromas or "cartilage rests". The ages of the patients at presentation were 55, 63 and 84 years and all were women. Two patients died with pulmonary metastases within six months of the onset of clinical symptoms. Despite their intimate relationship to the enchondromas, none of the osteosarcomas could be shown histologically to have arisen from tumour cartilage. It appears probable that these are cases in which independently arising tumours have merged to form a so-called "collision" tumour, but the possibility that they could have been derived by dedifferentiation of a previously benign neoplasm cannot be discounted.

Subperiosteal osteoid osteoma in a juxta-articular site presents a diagnostic challenge. The clinical features of joint stiffness, synovitis, muscle atrophy and local warmth may suggest arthritis rather than osteoid osteoma, while radiographs, bone scans and angiograms may not be diagnostic. We describe four cases of this rare condition.

We report and discuss a combined anterior, anterolateral and posterior approach to the lower cervical spine. This was used for the radical resection of a recurrent osteoblastoma which involved the lateral mass, pedicle, and lamina of the sixth cervical vertebra.