A study of structures which obstruct reduction of hip dislocation was performed on 15 hips by magnetic resonance imaging (MRI). Before treatment started, MRI studies were performed on 10 patients, six of whom were treated conservatively, after which further MRI studies helped to establish a concentric reduction. In the other four conservative treatment failed and they were operated on; in them the MRI studies were compared with arthrographic and surgical findings. In all but one of these 10 patients, MRI enabled us to differentiate between an everted and an inverted limbus. In five other patients with unsatisfactory development of the hip following closed reduction, MRI was compared with earlier arthrographic studies. MRI provided accurate anatomical information which would not have been obtained by arthrography. It clearly has great potential in assisting the surgeon to select the appropriate form of treatment.

The frequency of slipping and osteoarthritis of the contralateral hip was recorded in 260 patients with slipped upper femoral epiphysis between 1910 and 1960. Twenty-three of these patients (9%) had primary bilateral slipping, 32 (12%) had a contralateral slip diagnosed later during adolescence and a further 104 (40%) had signs of contralateral slipping at follow-up 16 to 66 years later, giving a total of 159 cases (61%) with bilateral slips. Of the 104 slippings diagnosed at follow-up, 25% showed osteoarthritis. It is concluded that, with a slipped epiphysis, prophylactic contralateral pinning should be performed to avoid slipping and to reduce the risk of osteoarthritis.

We report the replacement of 42 hips in 34 adults with untreated congenital dislocation. We used Charnley low friction implants, cementing the cup at the level of the true acetabulum after deepening and enlarging it by our own technique of cotyloplasty. Results were evaluated in 38 hips after a mean of 5.5 years. All the patients showed marked improvement, with no infection and, as yet, no late revision. The technical difficulties of the operation and the complications are discussed.

Forty-four rabbits were operated on when five weeks old; in one group a 2 mm drill-hole was made in the intercondylar portion of the right femur across the central portion of the growth plate up to the diaphysis, while in the other group a similar drill-hole of 3.2 mm was made. At 3, 6, 12 and 24 weeks after operation, specimens from the growth plates of both femora were analysed using radiographic, microradiographic, histological and histomorphometric techniques. It was found that destruction of 7% of the cross-sectional area of the growth plate caused permanent growth disturbance and shortening of the femur.

We studied intracapsular pressure in 50 patients with Garden Grade I and II subcapital fractures. Before operation pressures varied from zero to 320 mmHg, 16 patients having an intracapsular pressure of over 80 mmHg. The pressure was increased considerably by medial rotation and decreased by lateral rotation and especially by semi-flexion. From zero to 36 ml of blood was aspirated; the amount did not correlate with the intracapsular pressure. Of 25 patients who were also examined by scintimetry, 13 had reduced uptake at the femoral head before aspiration, and nine of these showed a marked increase in uptake after aspiration. Intracapsular tamponade of the hip may be one reason for the occasional occurrence of segmental collapse of the femoral head after subcapital fracture with minor displacement.

It has been shown that raised intracapsular pressure causes avascular necrosis of the femoral head in experimental animals, but the relevance of this to clinical fractures of the femoral neck is controversial. We have studied 19 patients with intracapsular fractures of the femoral neck by pressure measurement and by ultrasonography to demonstrate capsular distension. The intra-articular pressure in Garden Grade I and II fractures averaged 66.4 mmHg with a maximum of 145 mmHg. In 10 Garden Grade III and IV fractures the average pressure was 28 mmHg with a maximum of 65 mmHg. Most of the recorded intracapsular pressures were high enough to have caused possible vascular embarrassment, and it is suggested that early decompression of the haemarthrosis should be considered.

One hundred and twenty-seven consecutive patients with displaced subcapital fractures of the femoral neck (Garden Grade III or IV) all under 80 years of age and independently mobile, were randomly allocated to fixation with either double divergent pins or a single sliding screw-plate device. The incidence of non-union and infection in the sliding screw-plate group was significantly higher, and we believe that when internal fixation is considered appropriate multiple pinning should be used. Mobility after treatment was disappointing in about half of the patients, and we feel that internal fixation can only be justified in patients who are physiologically well preserved and who maintain a high level of activity.

The driving reactions of 25 patients were assessed before and after operation for hip replacement. Driving reactions were tested by monitoring the delay and force of brake application after an emergency signal, using a simulated driving control system. Fifteen normal subjects were also tested. Statistical analysis demonstrated significant differences between patients with either left or right hip replacement and between pre- and postoperative testing. Most patients improved by the eighth week, but some had deteriorated and did not recover until re-tested eight months after operation. It is concluded that for most patients eight weeks' delay for return to driving is appropriate, but for a minority of patients with right hip replacement recovery of reaction speed requires longer rehabilitation.

Intramedullary locking nails have proved to be of considerable advantage when treating complex, comminuted or segmental femoral shaft fractures. We have reviewed 117 patients with 120 femoral shaft fractures treated with the Strasbourg device. These included 20 compound fractures, 13 pathological fractures and two non-unions. Rehabilitation and union rates have been very satisfactory and there have been no serious infections in the series. Comminution of the proximal femur has occurred in six patients and there have been three femoral neck fractures, but all of these have healed without further complications.

We have reviewed 85 knees in 71 patients after total-condylar posteriorly stabilised (Insall-Burstein) knee replacement with an average follow-up of five years. Excellent or good results were obtained in 90% with an average maximum flexion of 98 degrees. The four poor results (5%) included two with deep infection, one with patellar dislocation and one with loosening. Four other knees (5%) showed signs of probable tibial loosening, but the patients were asymptomatic, the clinical results had not deteriorated with time and lucent lines had not progressed. Varus alignment of the knee and a varus tilt of more than 2 degrees of the tibial component correlated with the incidence of lucent lines around the tibial implant. No patellar stress fractures were seen but impingement symptoms were present in 20%, although they were troublesome in less than half of them. The virtue of the prosthesis lies in its versatility for use in the severely deformed joint.

Since 1974, we have made a prospective study in Bristol of the results of unicompartmental knee replacement using the St Georg sledge prosthesis. A total of 115 knees in 100 patients have been followed up for 2 to 12 years (mean, 4 years 9 months). Results have assessed both by the Bristol knee score and by survivorship studies on the total series of 138 knees. Results were excellent or good in 86% and fair or poor in 14%. The survivorship study (based on a definition of failure which included significant pain or a dissatisfied patient or the need for revision) showed a cumulative success rate of 76.4% at six years, with no further failures after that time. Seven knees have been revised, in most cases for deterioration of the contralateral compartment. The operation is recommended as a satisfactory and durable form of treatment for osteoarthritis affecting a single tibiofemoral compartment.

We report the results of 23 soft-tissue release procedures in 15 patients who had juvenile chronic arthritis. The operation, which includes hamstring tenotomies and posterior capsulotomy, is a safe and effective way of eliminating contracture, relieving pain and improving function.

Forty-five patients with fractures of the tibial spine were reviewed 3 to 10 years after injury in order to determine the degree of residual laxity of the cruciate or collateral ligaments. After fractures which had been partially or completely displaced, some anterior cruciate laxity was evident, even if patients were asymptomatic. It was also found that an anatomical reduction did not prevent either laxity or some loss of full extension of the knee.

We reviewed 26 fractures involving the distal physis of the tibia to identify the patterns of formation and displacement of the subsequent growth disturbance lines. Twenty-one patients showed a regular "normal" pattern of line and healed with no deformity. Three patients had medical physeal arrest revealed by abnormal lines. Two other cases had a minor central physeal arrest without subsequent deformity. The pattern and character of the growth disturbance line can provide an early warning of potential deformity.

The feet of 13 spina bifida patients who had undergone triple arthrodesis in adolescence were reviewed at an average of 10 years after operation. Fifteen of 18 feet were considered satisfactory (83%); of the remaining three, two had recurrent planovalgus deformities and one a painful pseudarthrosis. Three feet had required revision of the triple arthrodesis, and there was one postoperative infection. No patient had lost ambulatory status as a result of foot problems and eight of the 10 patients who previously needed calipers were able to discard them or to use lighter ones.

In a retrospective study we compared the results of 31 Wilson and 31 Hohmann osteotomies of the first metatarsal in the treatment of hallux valgus. There were no differences between the two operations in terms of patient satisfaction, pain relief, appearance, footwear and walking ability. First metatarsal shortening was the same after both operations, and the degree of shortening was unrelated to either the clinical or the pedobarographic findings. Although the long-term radiographic changes after the Hohmann osteotomy were more worrying, the pedobarographic patterns tended to be worse after the Wilson osteotomy. There were no poor results and the numbers of feet with the same final grade were identical in each group. However, there was abnormal loading of the lateral metatarsal heads after both osteotomies when compared with the normal foot, and hallux-contact time during the stance phase was also significantly reduced after osteotomy.

The statistical quality of 103 original articles published in The Journal of Bone and Joint Surgery (British Volume) in 1984 was assessed. Some papers were found to be deficient: thus, it was not always clear how series were selected and sometimes neither the data nor the results were clearly presented. Sample sizes were frequently inadequate for the conclusions reached and statistical techniques should have been used more frequently. A majority of papers were descriptions of case series for which no comparative data were made available. It is suggested that collaborative research would best advance knowledge about the relative benefits of various managements, and that statistical advice could make a substantial contribution.

Thirty-six patients with 39 fresh fractures of the calcaneus were investigated by standard radiography and by computerised tomography. It was found that the size and disposition of the fracture fragments and the degree of involvement of the posterior facet of the subtalar joint were more clearly shown by CT scanning. We recommend this technique for assessment and particularly for pre-operative planning.

A retrospective study of 260 industrial amputees was undertaken to determine the long-term functional results of partial foot amputations following trauma. Follow-up ranged from 1 to 68 years with a mean of 16 years. Of 113 partial foot amputees (118 amputations) who had retained their original amputation, the functional end-results were 43% good, 38% fair and 19% poor. Lisfranc and Chopart amputations were better than those at transmetatarsal or digital levels. Of 260 initial amputations 49 (19%) were revised to a Syme's or a below-knee amputation.

We report 40 cases in one family of an autosomal dominant bone dysplasia, which, though similar in some aspects to Paget's disease, seems unique in some features and in its natural history. The disease shows both general and focal skeletal changes, the latter being mainly in the limbs with an onset from the second decade. Progressive osteoclastic resorption is accompanied by medullary expansion which leads to pain, severe deformity and a tendency to pathological fracture. The serum alkaline phosphatase and urinary hydroxyproline are variably elevated, while other biochemical indices are normal. Most patients had an associated deafness of early onset and loss of dentition. No previous description of this disease has been found in the literature.

Thirty-four patients with adolescent idiopathic scoliosis were assessed by radiography and the integrated shape imaging system (ISIS) both before and after spinal surgery. Twenty-seven patients underwent Harrington instrumentation, after which lateral indices of curvature were significantly improved, but changes in the transverse plane were less pronounced. Sublaminar wiring was carried out in two patients whose thoracic lordosis was corrected by the surgery. Five patients whose severe deformity had persisted after previous spinal surgery underwent costoplasty, which resulted in a significant improvement in back shape measurements. We conclude that the cosmetic deformity of the back in scoliosis is only partially corrected by operations on the spine itself, whilst costoplasty addresses the problem directly, and improves the surface shape.

In a prospective study we attempted to define the role of lumbar discography in the investigation of patients with low back pain with or without non-dermatomal pain in the lower limb. The records of 195 patients were studied at least two years after a technically successful operation. Of 137 patients in whom discography had revealed disc disease and provoked symptoms, 89% derived significant and sustained clinical benefit from operation. Of 25 patients whose discs showed morphological abnormality but had no provocation of symptoms on discography only 52% had clinical success. These findings support the continued use of lumbar discography for the investigation of this particular group of patients.

Of 232 patients with evidence of lumbar spinal stenosis, 13 had symptoms of meralgia paraesthetica. Myelography demonstrated that in all but one of these 13 cases the L3-4 level was involved by stenosis; in 12 matched control patients with spinal stenosis, none had involvement at this level. We found that both the ligamentum flavum and the laminae at L3-4 level were thicker than in a control group. Decompressive laminectomy at the L3-4 level significantly reduced the area of hypo-aesthesia in the thigh, effecting complete cure in seven of the 11 cases. Meralgia paraesthetica is not uncommon in patients with spinal stenosis and is referable to changes at the L3-4 level. It seems that many cases of meralgia may have a spinal origin.

Experimental work has shown that dislocation of the shoulder may involve disruption of the capsule from its lateral humeral attachment. We report two patients with recurrent dislocation due to this injury. Lateral repair gave good results. It is suggested that this injury be considered and looked for when glenoid labral injury is minimal or absent.

The use of prolonged halo stabilisation in a child is increasingly indicated for trauma and congenital instability of the cervical spine, but complications of pin fixation in this age group are frequent. We have analysed four aspects of the mechanics of the halo pin: the forces applied by each of six surgeons was shown to vary widely, penetration of the inner table occurred relatively easily, friction at the pin-halo interface influenced forces, and the skull thickness measured by CT scan varied from 1.1 mm to 4.3 mm in children under six years of age. We recommend CT scanning of the skull before elective halo application in young children to ascertain the safest pin sites.

Three cases of anterior interosseous nerve palsy were diagnosed after internal fixation of fractures of the proximal radius. The suggestion that the nerve was injured at operation by bone-holding forceps was supported by operations on 12 cadaver forearms, in which the nerve was frequently trapped. Care should be taken to place such forceps in a subperiosteal plane.

Supracondylar osteotomy for traumatic cubitus varus is usually considered to be difficult, and to have a significant incidence of complications. Most difficulty is in maintaining correction after operation. We report 20 osteotomies performed by a modification of French's technique and managed postoperatively with the elbow extended. When a plaster splint was used only three of seven cases had good or satisfactory results, two requiring revision. Postoperative management by straight arm traction maintained correction and achieved a good or satisfactory result in all 13 cases. This new technique is recommended.

Excision of the lunate was performed for 18 patients with Kienbock's disease; 14 were followed up for an average of almost 12 years. Carpal collapse progressed with time, but rearrangement of the remaining carpal bones preserved a satisfactory range of movement and grip strength. Degenerative changes were not severe. All the patients had relief of pain, were able to carry out their normal activities, and all but two could perform strenuous activities.

A consecutive series of 100 cases of wrist injury, other than those referred with a radial fracture, have been reviewed to determine the incidence of acute scapholunate instability; a "clenched fist" radiograph was used in addition to the routine scaphoid views. Of 19 patients with an increase in the scapholunate gap, five were eventually considered to have significant scapholunate instability, two in association with Colles' fractures. Injuries producing significant ligamentous damage and carpal instability may be as common as scaphoid fractures. They require special consideration in diagnosis and management.

Inter-observer agreement and reproducibility of opinion were assessed for the radiographic diagnosis of union of scaphoid fractures on films taken 12 weeks after injury. Weighted kappa statistics were used to compare the opinions of eight senior observers reviewing 20 sets of good quality radiographs on two occasions separated by two months. There was poor agreement on whether trabeculae crossed the fracture line, whether there was sclerosis at or near the fracture and on whether the proximal part of the scaphoid was avascular. As a consequence, agreement on union also was poor; it appears that radiographs taken 12 weeks after a scaphoid fracture do not provide reliable and reproducible evidence of healing.

Threaded acetabular components are widely used in cementless total hip replacement, despite a poor understanding of the nature of the bone-implant interface. We have examined one case in which the threaded titanium ring appeared to be well incorporated with no discernible radiolucency. Microradiography and histology surprisingly showed that the threads were entirely encapsulated in fibrous tissue. This raises doubt about the relevance of plain radiography to the analysis of the acetabular interface.

A model was developed in the dog to allow both the metaphysis and epiphysis of the distal ulnar growth plate to be microsurgically revascularised from the pedicle of the anterior interosseous vessels. With both circulations revascularised, grafts retained their structural integrity and growth continued at rates only slightly less than normal (mean 85%). If either or both circulations were not revascularised, growth rates were lower and were associated with skeletal collapse in the ischaemic bone segment.

We investigated the feasibility in the dog of using transfers of the distal ulna into the radius either as growth plate replacements or as accessory growth plates in the diaphysis. Preliminary work determined the most satisfactory method of skeletal fixation. The experimental study showed that transfers used as growth plate replacements grew at almost normal rates, uniting with the recipient bone in a mean of 7.1 weeks. Transfers into the diaphysis initially nearly doubled the growth rate of the radius, although in the long-term results were unsatisfactory, because of fracture of the graft after a mean period of 8.2 weeks.

The right sciatic nerve of 50 one-month-old male rats was cut under general anaesthesia. Groups of animals were sacrificed at intervals of up to 12 weeks after operation and the length of the femora, tibiae and first and fifth metatarsals were measured with a caliper accurate to 0.05 mm. From the first week, both metatarsals were between 3% and 5% shorter on the denervated side, but there was no further increase of the discrepancy. The femora were less than 1% longer in the denervated limb at the second and eighth week. No difference was found between the lengths of the tibiae. The various factors which could possibly be responsible for these findings are discussed.

The use of an osteocutaneous free fibular graft as a single-stage reconstructive procedure for composite tissue loss is increasingly common. Detailed anatomical study in cadavers of the blood supply to the graft demonstrates cutaneous arteries arising from the peroneal artery and then passing along the posterior surface of the lateral intermuscular septum. These vessels pierce the crural fascia and then ramify to supply the skin. Knowledge of the vascular anatomy of the skin overlying the fibula is essential to the success of the graft.

Antibiotic levels in bone and fat were measured in patients undergoing knee replacement to determine the time that should elapse between intravenous injection and tourniquet inflation. The tissue levels increased progressively with time, and there was wide variation in absorption rate between patients and between the two cephalosporins assessed. Five minutes should probably be left between systemic injection and inflation of the tourniquet, though two minutes may be long enough for drugs which are rapidly absorbed.