When the Oxford unicompartmental meniscal bearing arthroplasty is used in the lateral compartment of the knee, 10% of the bearings dislocate. A radiological review was carried out to establish if dislocation was related to surgical technique. The postoperative radiographs of 46 lateral unicompartmental arthroplasties were analysed. Five variables which related to the position and alignment of the components were measured. Dislocations occurred in six knees. Only one of the five variables, the proximal tibial varus angle, had a statistically significant relationship to dislocation. This variable quantifies the height of the lateral joint line. The mean proximal tibial varus angle for knees the bearings of which had dislocated was 9° and for those which had not it was 5°. In both groups it was greater than would be expected in the normal knee (3°). Our study suggests that a high proximal tibial varus angle is associated with dislocation. The surgical technique should be modified to account for this, with care being taken to avoid damage to or over-distraction of the lateral soft tissues

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9° . sd. 6.7° for patients and 11.9° . sd. 3.6° for the control group (p < 0.001). The mean height of the articular cartilage was 91.3° . sd. 8.3° for the patients and 83.3° . sd. 7.7° for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group. Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects

Isolated dislocations of the navicular are rare injuries; we present our experience of six cases in which the navicular was dislocated without fracture. All patients had complex injuries, with considerable disruption of the midfoot. Five patients had open reduction and stabilisation with Kirschner wires. One developed subluxation and deformity of the midfoot because of inadequate stabilisation of the lateral column, and there was one patient with ischaemic necrosis. We believe that the navicular cannot dislocate in isolation because of the rigid bony supports around it; there has to be significant disruption of both longitudinal columns of the foot. Most commonly, an abduction/pronation injury causes a midtarsal dislocation, and on spontaneous reduction the navicular may dislocate medially. This mechanism is similar to a perilunate dislocation. Stabilisation of both medial and lateral columns of the foot may sometimes be essential for isolated dislocations. In spite of our low incidence of ischaemic necrosis, there is always a likelihood of this complication

We report the case of a 22-year-old woman who underwent plate and screw fixation for a traumatic left acetabular fracture and fixation with cancellous screws for an associated femoral neck fracture. Two months later, the internal fixation became infected and was removed. This resulted in a painful high dislocation of the hip. We solved the problem with continuous soft-tissue distraction using a fully implantable motorised distraction nail in order to reduce the proximal femur prior to total hip arthroplasty. To our knowledge, this is the first time that reduction of a high dislocation of the hip has been performed using such a system

Out of a total of 91 patients with traumatic posterior dislocation of the hip treated between 1936 and 1974 in the Mansfield area, 81 patients were reviewed. The average follow-up period was 12.5 years, although there was a large number of cases with a follow-up of more than 15 years and a smaller number with a follow-up of 30 years. The overall results were surprisingly poor despite early reduction of the dislocation in the majority of cases. We found that 15 years after simple dislocation 24 per cent of the cases had a poor result by both clinical and radiological criteria, but in the more severe grades of initial injury the results became worse, with 73.3 per cent of the patients graded as fair and poor, and only 26.7 per cent graded excellent or good

1. A case of recurrent posterior subluxation of the shoulder is described. After failure of a soft-tissue repair, a posterior bone block operation was performed. 2. The distinction between traumatic dislocations with tearing of the capsule or of the glenoid labrum, and habitual luxations from laxity of the capsule, is emphasised. Although the anterior rim of the glenoid was detached in this case, it is considered to fall into the latter category. 3. A posterior bone block provides a simple and efficient form of repair in this type of case. It is free from the disadvantage of causing limitation of rotation at the shoulder joint; it employs a principle which might well merit more application than at present in the repair of anterior dislocations

We have studied 105 patients with 107 acute, primary, dislocations of the glenohumeral joint seen between January 1, 1991 and July 1, 1994. The mean time of follow-up was 71 months (46 to 91). In 34% the injury occurred during a sports activity and in 28% at home. The bias toward sport was even greater in patients less than 40 years of age, and in men. In patients older than 40 years of age, and in women, the dislocation occurred more often at home. The overall probability of recurrence within four years was 26%. Age was the most significant prognostic factor in recurrence which took place in 64% of patients less than 20 years of age and in 6% of those older than 40 years. Statistically, there was no difference between the rates of recurrence in patients who were active in sport and those who were not. The mean Rowe score for the whole group was 87 (15 to 100). Associated fractures were found in 20 patients (19%) and nerve injuries in 22 (21%). None of those in whom a fracture of the greater tuberosity was seen subsequently suffered a recurrent dislocation. At follow-up we found that 36 patients (34%) had not returned to their former employment but in only 2% was this owing to the injured shoulder

The most common injury in rugby resulting in spinal cord injury (SCI) is cervical facet dislocation. We report on the outcome of a series of 57 patients with acute SCI and facet dislocation sustained when playing rugby and treated by reduction between 1988 and 2000 in Conradie Hospital, Cape Town. A total of 32 patients were completely paralysed at the time of reduction. Of these 32, eight were reduced within four hours of injury and five of them made a full recovery. Of the remaining 24 who were reduced after four hours of injury, none made a full recovery and only one made a partial recovery that was useful. Our results suggest that low-velocity trauma causing SCI, such as might occur in a rugby accident, presents an opportunity for secondary prevention of permanent SCI. In these cases the permanent damage appears to result from secondary injury, rather than primary mechanical spinal cord damage. In common with other central nervous system injuries where ischaemia determines the outcome, the time from injury to reduction, and hence reperfusion, is probably important. . In order to prevent permanent neurological damage after rugby injuries, cervical facet dislocations should probably be reduced within four hours of injury

Thirty-three children with traumatic dislocation of the hip who had been treated at the Hospital for Sick Children between 1960 and 1977 were reviewed. The amount of trauma causing dislocation of the hip in younger children was less than that for older children. The most frequent complication was soft-tissue interposition which usually required a posterior arthrotomy to clear the interposed tissue. Less frequent complications included avascular necrosis, redislocation of the hip and an irreducible hip. Nineteen children were reviewed with an average follow-up time of 10 years. Clinical examination indicated that 84 per cent of these hips were normal but the radiographs showed that 47 per cent of the dislocated hips had a coxa magna of two millimetres or more. There was no correlation between the development of coxa magna and the clinical result

Retrieval studies of total hip replacements with highly cross-linked ultra-high-molecular-weight polyethylene liners have shown much less surface damage than with conventional ultra-high-molecular-weight polyethylene liners. A recent revision hip replacement for recurrent dislocation undertaken after only five months revealed a highly cross-linked polyethylene liner with a large area of visible delamination. In order to determine the cause of this unusual surface damage, we analysed the bearing surfaces of the cobalt-chromium femoral head and the acetabular liner with scanning electron microscopy, energy dispersive x-ray spectroscopy and optical profilometry. We concluded that the cobalt-chromium modular femoral head had scraped against the titanium acetabular shell during the course of the dislocations and had not only roughened the surface of the femoral head but also transferred deposits of titanium onto it. The largest deposits were 1.6 μm to 4.3 μm proud of the surrounding surface and could lead to increased stresses in the acetabular liner and therefore cause accelerated wear and damage. This case illustrates that dislocations can leave titanium deposits on cobalt-chromium femoral heads and that highly cross-linked ultra-high-molecular-weight polyethylene remains susceptible to surface damage

Over the 10-year period 1969 to 1978, 271 consecutive cases of congenital dislocation of the hip were diagnosed at birth. Standard anteroposterior radiographs of the pelvis were obtained routinely and were analysed retrospectively. The medial gap, a measure of the separation between the proximal femur and the pelvic wall, was found to be significantly increased in cases with unilateral or bilateral dislocation when compared to normal. A medial greater than five millimetres is indicative of femoral head displacement and is of value where the clinical diagnosis is uncertain. The rate of missed dislocation at birth was 0.6 cases per thousand. Treatment with the Malmo splint was the normal routine. The Pavlik harness was applied if splintage was poorly tolerated by the infant, or in the rare instance of limited hip abduction. Failure to maintain reduction by splintage occurred in 3.3 per cent. The incidence of pressure deformities of the femoral head was 2.95 per cent and there was a residual deformity in later childhood of 1.1 per cent. It is presumed that this lesion can be attributed to the effect of splintage and it was notably avoided in the later period of the review when greater mobility of the abducted hips was encouraged

A 20-year-old man sustained an open medial dislocation of the ankle without an associated fracture after a low-energy inversion injury. Prompt debridement and reduction with primary wound closure of the skin were performed without suture of the capsule. Immobilisation in a non-weight-bearing cast for 30 days followed by ankle bracing for two weeks and subsequent physiotherapy, produced full functional recovery by three months. At follow-up at one year there was a full range of pain-free movement, although the radiographs and MR scan showed early post-traumatic degenerative change at the medial aspect of the tibiotalar and the calcaneocuboid joints

Only two cases have been reported of congenital dislocation of the hip in infants born after extrauterine pregnancies. We report a further two and discuss the management and the variable outcome. These cases seem to confirm that congenital dislocation of the hip is associated with moulding forces rather than being a teratological abnormality

The authors wished to determine the late results of the Hauser operation, with special reference to the development of osteoarthritis. Predisposing factors associated with recurrent dislocation of the patella were also investigated. Thirty-five patients with forty-our surgically treated knees attended for review, ten to twenty-fve (aerage sixteen) years after operation. Two patients had subsequently undergone excision of the patella. Ten patients gave a family history of recurrent dislocation of the patella and seven patients showed generalised joint laxity. Pain was present in eight knees before operation and was present in thirty-three knees (75 per cent) at the time of review. Patellar crepitus was present in thirty-seven out of forty-two knees (88 per cent) at review. Osteoarthritis was present in thirty out of forty-two knees (70 per cent). The incidence increases with time since operation and the present age of the patient. It is concluded that the Hauser operation prevents further dislocation but does not prevent the development of osteoarthritis. It is possible that a simple soft-tissue operation which effectively prevents dislocation might achieve the same results

1. Attention is drawn to the importance of taking tangential radiographs of the patella in all cases of injury to the knee, especially when there is difficulty in distinguishing between recurrent dislocation of the patella and tear of a meniscus. 2. New bone formation along the medial side of the patella confirms a diagnosis of recurrent dislocation. 3. The importance of Coleman's original observations is stressed

Twenty-one cases of the Charnley low-friction arthroplasty were revised because of recurrent or irreducible dislocation. Three main reasons for this revision, usually in combination, were identified: loss of the abductor mechanism due to trochanteric detachment; shortening of the limb due to high placement of the socket or low section of the femoral neck; and malorientation of the components. Sixteen patients had no further problems after revision. One patient had a single dislocation, four had more than one dislocation although they managed to cope with them and did not require a further revision

Metal-on-metal (MOM) is a commonly used bearing notable for its ‘suction fit’ when lubricated. In this study, we examined the capacity for MOM bearings to protect against dislocation after total hip replacement (THR). We undertook a clinical investigation to compare the rate of dislocation of MOM bearings with those of ceramic-on-polyethylene (COP) bearings and found that one MOM bearing dislocated in a series of 109 hips (0.9%) compared with nine of 145 hips (6.2%) in the COP group (p = 0.02). We also performed an in vitro investigation comparing the peak forces generated during forced separation of the two bearings of the same dimensions at velocities from 1 to 50 cm/s. This revealed that the MOM bearing generated significant resistance to separation at all velocities (maximum mean 24 N), whereas the COP did not (maximum mean 1.9 N, p < 0.001). We conclude that MOM bearings are more stable to dislocation than COP bearings as a result of the interfacial forces provided by a thin, lubricating fluid

A patient with recurrent dislocation of the hip is described. The initial injury had been a posterior dislocation without associated fracture of the acetabular wall, and the hip had not been immobilised or protected from weight-bearing during treatment. Exploration of the hip for recurrence revealed disruption of the posterosuperior acetabular labrum with formation of a pouch between the posterior acetabular wall and the short rotator muscles. We have found no previous report of this lesion, which resembles a Bankart lesion of the shoulder. Repair using a bone block is described

A few points in this report deserve to be stressed. Indications–It is important that the orthopaedic surgeon should decide at a very early stage which of the two methods, closed or open, he must use. These do not exclude each other but are on the other hand complementary. Nowadays the dislocated hip can be reduced by open operation with a very good chance of lasting success. This should be carried out if a hip cannot easily be reduced otherwise, or if there is any doubt that closed reduction has been successful–and as early as possible, preferably before the age of three years. Technique–Ample exposure of the joint and removal of all obstacles to reduction are important. Reduction must be complete and stable but without stress, and there must be no interference with the articular bone and cartilage. After-care–Reduction, however perfect, is only the first step towards recovery. The hip must be observed carefully and the most suitable moments for mobilisation and for walking must be chosen; this calls for nice judgment. When it is clear that the roof of the acetabulum is not developing or that persistent valgus and anteversion may encourage subluxation, a secondary operation should be undertaken at once. Radiography is necessary about every three months for the first two years. Assessment of results–With a strict system of assessment, like McFarland's, we have observed 68·3 per cent favourable results in 171 hips treated by open reduction. It is obvious that the problem of congenital dislocation of the hip has not yet been completely solved. But if we review the progress of recent years we come to the encouraging conclusion that much has already been achieved, and that the efforts of the many orthopaedic surgeons who have dedicated themselves to the treatment of congenital dislocation of the hip have not gone unrewarded

We measured torsion of the humeral head in 38 patients (40 shoulders) with recurrent anterior dislocation of the shoulder (RADS) and in 40 normal subjects. We found a reduced mean retroversion in the patients with RADS at 4.3 +/- 10.56 degrees (17 degrees anteversion to 32 degrees retroversion) as compared with 16.1 +/- 11.07 degrees in the control group (0 degrees to 49 degrees) (p = 0.0001). There was anteversion in 11 of the 40 shoulders in the RADS group (27.5%) and in none of the control group. The first dislocation had occurred after minimal force in 18 of 25 patients with less than 10 degrees retroversion, but in only three of 15 with over 10 degrees retroversion. We conclude that decreased retroversion of the humeral head is often associated with RADS and with first dislocation of the shoulder caused by minimal force