A case is reported of a patient who presented with a soft-tissue tumour at the site of a total hip replacement. This tumour proved to be a malignant fibrous histiocytoma.

The occurrence of an osteosarcoma at the site of a cobalt-chrome total hip replacement is described, and the possibility of the tumour arising as a result of the liberation of cobalt particles is discussed. The experimental and clinical evidence relating tumour formation to the presence of particulate metals, and to the presence of solid and particulate polyethylene, is presented. It is considered that the risk of tumour formation at the site of any total hip replacement is very small.

Seven hips with protrusio acetabuli which showed complete or partial resolution of the protrusion after replacement with Ring's prosthesis are reported. It is suggested that this prosthesis offers a simple and effective method of treating painful protrusion into the pelvis; it allows healing of the medial wall of the acetabulum while avoiding many of the hazards of other methods of treatment.

In order to improve the fixation of the stem in primary Charnley low-friction arthroplasty, the medullary canal was routinely closed off with a cancellous bone block. A prospective study of 611 consecutive arthroplasties were carried out between 1 and 5 1/2 years (average 2 years and 9 months) after operation. There were two cases of radiological loosening of the stem, both of which could have been avoided. Five other patients showed demarcation of the bone-cement junction at the calcar; two of these are considered to be "at risk" of loosening. There was no evidence of radiological loosening of the stem in 604 cases and the method is recommended for routine use in primary total hip arthroplasty.

Three cases of severe osteogenesis imperfecta are reported. Each was treated by closed intramedullary rodding, combined with osteoclasis to correct deformity. Operation was performed within a few months of birth. Both tibiae and both femora were stabilised in one operation, using x-ray image intensification to monitor placement of the rods. The technique used to insert the rods is described. The procedure appeared to be entirely satisfactory in reducing the incidence of fractures and it allowed the affected infants to be handled much more easily.

Of 47 patients with spina bifida who had had transplantation of the iliopsoas more than 10 years previously, 32 (68%) were community walkers, 3 were household walkers and 12 were non-walkers. Comparison with other published reports showed that, at the very least, the patients reviewed had not had their walking ability jeopardized by the inevitable loss of hip flexor power. Furthermore, all but three of the community walkers were able to climb and descend stairs. There was a high proportion of non-walkers in those patients whose operation had been performed in the first year of life and such early surgery is no longer recommended. We also found that the pre-operative assessment of muscle power had, in some patients, been inaccurate. Finally, we found that, at review, the power of the transferred muscles was poor, suggesting that transplantation is beneficial because it achieves permanent and major reduction in hip flexor power; this usually prevents recurrent hip flexion deformity and dislocation.

Three hundred and nineteen patients who had chondromalacia patellae and persistent patellofemoral pain after six months of conservative management underwent arthroscopy and arthroscopic surgery. The results in four aetiological groups were reviewed at one year and five years after operation. Morbidity was minimal. Lavage produced early remission in all groups. Shaving offered a particular advantage in the post-traumatic group. Lateral release plus shaving and lavage was beneficial in the group with maltracking patellae and in half of the idiopathic group. In the group with unstable patellae, lateral release produced good results in only one in four patients. In conclusion, we consider that arthroscopic surgery has a useful role to play in the management of chondromalacia patellae.

Late degenerative changes are known to follow meniscectomy, but there is little agreement on their incidence or on which patients are most at risk. A total of 210 patients have been reviewed 10 to 22 years after meniscectomy, and long leg radiographs taken of both knees. Radiological degeneration was seen in 18%, while 7% had significant symptoms and signs. Statistical analysis showed increased changes in older patients, in those with abnormal leg alignment, and in those who had undergone lateral as against medial meniscectomy. Our findings emphasise the important mechanical function of the meniscus and support the current cautious approach to meniscectomy, especially for patients in high risk groups. They also indicate the value of early high tibial osteotomy for symptomatic varus deformity after medial meniscectomy.

The revascularisation and remodelling of allografts used to replace the anterior cruciate ligament in the canine knee were studied by microangiographic, histological and biomechanical methods. The 26 allografts were obtained from the patellar tendons of other dogs and were stored by deep freezing. In a control study a strip of patellar tendon from the same leg was used as an autologous free graft. Microangiography showed that the allografts had been revascularised from the sixth postoperative week, and had later developed an intrinsic vascular pattern similar to that of a normal anterior cruciate ligament. Histologically, the allograft regained a fibrous framework similar to that of a normal ligament, and showed no evidence of immunological rejection. Biomechanical tests on the allograft replacements showed that their mean maximum tensile strength at 30 weeks was about 30% of that of the control ligaments. There were no significant differences between the mechanical properties of the allografts and the autografts.

A retrospective review of medial compartment arthroplasty in 22 patients (22 knees) is reported. The operations were performed between 1973 and 1978. Eighty-six per cent were rated good or excellent using the knee rating system devised by the Hospital for Special Surgery, New York. Excellent or good results were achieved in six patients who had previously had a high tibial osteotomy. At the time of follow-up significant loosening had not occurred, although progression of patellofemoral disease was noted. This study supports the promising results reported for unicompartmental resurfacing arthroplasty in the elderly.

Mechanical abnormalities of the patellofemoral joint are among the many causes that have been suggested for adolescent knee pain. This study seeks to identify these factors. Measurements of joint mobility and lower limb morphology were made on 446 pupils at a comprehensive school, 136 of whom had suffered knee pain in the previous year. The pupils with symptoms enjoyed sporting activities significantly more than their symptom-free contemporaries. Joint mobility, the Q-angle, genu valgum and anteversion of the femoral neck were not significantly different between those pupils with and those without anterior knee pain. Data on lower limb morphology of normal adolescents are presented. Examination of 52 hospital outpatients aged 13 to 36 years with anterior knee pain produced results comparable with those for the pupils. It is concluded that chronic overloading, rather than faulty mechanics, is the dominant factor in the genesis of anterior knee pain in adolescent patients.

Talectomy was performed on 10 patients (15 feet) for club foot deformity in arthrogryposis multiplex congenita. These were reviewed after an average follow-up of eight years. At follow-up nine feet were plantigrade, and six had less than 15 degrees residual equinus at the ankle. All the feet were asymptomatic but had mild residual adduction of the forefoot and marked stiffness of the hindfoot. Seven feet developed spontaneous bony ankylosis in the tibiotarsal joint. The common technical errors were incomplete removal of the talus and incorrect positioning of the calcaneus in the ankle mortise.

Eighteen patients (34 feet) with arthrogryposis multiplex congenita treated by talectomy for rigid equinovarus deformity were reviewed. The average follow-up was 11 years. Twenty-four feet (71%) were considered satisfactory; the remainder were improved. Seven feet required further operations to correct recurrence of the deformity, but finally all could be fitted with boots or shoes and all patients could walk. The history of talectomy is reviewed and the operative details described.

Previous reports have suggested that the blood supply derived from the anterior tibial artery is absent or markedly diminished in 85% of severe, untreated club feet. To investigate these claims, we used a Doppler technique to study the arterial pulses in 40 children with 63 club feet. In feet with mild or moderate deformities the anterior tibial pulse was always present; in feet with severe deformities it was absent in two out of 30 feet in children under three years and in seven out of 18 feet in children over three years. These results confirm that the incidence of pulselessness increases with the severity and duration of deformity, but not to the extent previously suggested by angiographic studies. The significance of these findings is discussed.

Eighty-seven feet have been reviewed after arthrodesis of the first metatarsophalangeal joint stabilised by chromic catgut. Radiological union was present in 90% of patients at the mean review time of six years. Twenty-four patients had significant metatarsalgia before operation and only two failed to improve afterwards. Excellent or good subjective results were reported in 94% of patients at review. Chromic catgut is advocated as a simple and effective method of stabilising an arthrodesis of the first metatarsophalangeal joint.

Cadaveric lumbar spine specimens of "motion segments", each including two vertebrae and the linking disc and facet joints, were compressed. The pressure across the facet joints was measured using interposed pressure-recording paper. This was repeated for 12 pairs of facet joints at four angles of posture and with three different disc heights. The results were that pressure between the facets increased significantly with narrowing of the disc space and with increasing angles of extension. Extra-articular impingement was found to be caused, or worsened, by disc space narrowing. Increased pressure or impingement may be a source of pain in patients with reduced disc spaces.

The use of nuclear magnetic resonance (NMR) in the diagnosis of radicular pain due to lateral canal stenosis in 21 patients is reported. NMR was able to distinguish normal intervertebral discs from degenerate discs, and NMR evidence of reduction of epidural fat was more reliable than radiculography in identifying lateral root entrapment. NMR is an important advance in the investigation of lumbar radiculopathies.

We used a modification of the wake-up test to monitor spinal cord function in 102 consecutive scoliotic patients undergoing Harrington instrumentation. Four patients were found to have a neural deficit when they were awakened during the operation. Three recovered immediately after partial release of the distracting force; one required immediate removal of the rod and was left with a slight neural deficit. Using our method, we have encountered no problem in performing the wake-up test, although attention is drawn to the difficulty in repeating the test if the patient is re-anaesthetised with diazepam. There were no false negative results in this series.

Spondylolysis occurring after a spinal fusion is considered to result from operative damage to the pars interarticularis on both sides. Fourteen cases are reported, and compared with the 23 cases which have previously been published. The defects are usually recognised within five years of fusion, and usually occur immediately above the fusion mass. Other contributory causes may be: fatigue fracture from concentration of stress; damage and altered function of the posterior ligament complex; and degenerative disc disease immediately above or below the fusion. Fusion technique is critical, since virtually all cases occurred after posterior interlaminar fusions. This complication is easily overlooked in patients with recurrent back pain after an originally successful posterior spinal fusion.

Fractures of the scapula occur mainly from direct trauma involving considerable violence and associated injuries of the shoulder and thorax are common. In most cases early functional treatment gives good or excellent results. Operative treatment may, however, be indicated, especially with displaced intra-articular fractures, fractures of the glenoid rim associated with humeral head subluxation, or unstable fractures of the scapular neck. Between 1967 and 1981, we treated 37 such fractures by open reduction and stable osteosynthesis. We were able to follow up 33 cases (89%), of which 21 (64%) had complete functional recovery. The other 12 had varying degrees of pain, loss of mobility, and weakness. Overall, however, 79% of the patients had good to excellent results.

Between 1970 and 1982, 50 total elbow replacements were carried out for rheumatoid arthritis using the Stanmore prosthesis. A long-term follow-up of the 44 elbows available for review is presented. Thirty-four of these (77%) had good results, five were fair, and five were poor. The complications and limitations are discussed.

Fifteen patients with rheumatoid arthritis had 19 elbow arthroplasties with the Wadsworth type of surface replacement prosthesis. After a follow-up period averaging 30 months, 11 patients with 15 elbow arthroplasties were entirely satisfied with their freedom from pain and range of movement. Radiologically, however, the humeral component was loose in 10 of the 19 elbows and the ulnar component in 5. Two patients had reoperation, one to remove a prosthesis for early deep infection and one to exchange a humeral component which was loose. The risk of mechanical loosening is reduced by accurate positioning of the humeral component, but there is a high potential for failure. Changes in the design of the prosthesis and better instrumentation for alignment of the components are desirable. Prosthetic replacement of the elbow should still be regarded as experimental.

This paper describes a prosthesis for patients who have had a partial amputation of the hand, or who have congenital absence of all or part of the hand. The prosthesis incorporates a new concept whereby the grip is operated by flexion and extension of the wrist. A covering for the prosthesis has been developed using a silicone polymer which produces a lifelike flexible glove. Thirteen patients have so far been fitted with this type of prosthesis, which can give good function and cosmesis.

Two cases are reported of the late diagnosis of compartment syndrome secondary to alcohol and drug overdose. Surgical decompression at two and a half days and at six days, respectively, produced worthwhile recovery. Other reports are reviewed and a case is made for the value of decompression even when performed late, and for delayed and minimal excision of apparently necrotic muscle.

The use of Orthoplast cast-bracing to allow early hand function in the treatment of displaced Colles' fractures was investigated in 243 patients. They were randomly allocated into three groups: in the first a conventional Colles' type plaster was used; in the second an above-elbow cast-brace with the forearm in supination; and in the third a below-elbow cast-brace. Radiographic measurements were made at each stage of treatment, and the final anatomical result was scored using Sarmiento's (1975) criteria. Function was assessed at three months and at six months. The anatomical result was not influenced by the method of immobilisation but was related to the efficacy of reduction. Loss of position in the braces was no greater than in plaster. The functional result at three months also was uninfluenced by the method of immobilisation; it was, however, related to the severity of the initial displacement, and (to a lesser degree) to the anatomical result, an effect which was lost at six months. Early hand function and the supinated position advocated by Sarmiento were found to confer no anatomical or functional advantage; we could see no reason to change from the use of conventional plaster casts in the treatment of uncomplicated Colles' fractures.

The development of the iron-cored electromagnet as a stimulator of bony union is described. In a clinical trial extending over eight years, 80 patients were treated for various forms of failed union. Their results are presented, as well as tentative conclusions regarding the indications and efficiency of the method. The latest, fully-portable apparatus is described.

Malignant transformation of fibrous dysplasia to chondrosarcoma is rare. We report a case in which malignancy developed in an area of fibrous dysplasia in the ilium. We believe this to be the second reported case at this site. Treatment was by excision of the hemipelvis including the ala of the sacrum. A review of the literature is presented.

There are many operations for hallux valgus and hallux rigidus, but Keller's operation remains one of the most popular, particularly for the older patient. A prospective trial was carried out to compare the results of Keller's operation modified by Kirschner-wire distraction with those of the standard operation. The results suggest that there is no advantage in using temporary Kirschner-wire distraction; indeed, degenerative changes in the interphalangeal joint and a subjectively worse result may result from its use.

Sixty-two children were reviewed between 3 and 14 years (average 9.8 years) after flexor tenotomy for curly toes or hammer toes. No patients were aware of loss of flexor power in the toes. In only 5% of 188 toes was the operation unsuccessful. When the cause of failure was identifiable it proved to be that the scar crossed one or more flexor creases. None of the operated toes had an abnormally extended posture; only one toe was stiff and this resulted from tethering by a scar. It is concluded that open flexor tenotomy is an effective method for correcting curly toes and hammer toes in childhood. Pre-operative assessment must demonstrate that the resting length of the flexor tendons is unduly short, and that this shortening is the only cause of the deformity.