A method for direct measurement of the local pressures in the acetabular cartilage is described. Pressure transducers were introduced into the subchondral bone and positioned there in contrast with the cartilage: the transducers were calibrated in situ. Twelve cadaveric hips were prepared in this way and the pressures were measured with the joint loaded in flexion, extension, abduction, adduction, and in lateral and medial rotation. The highest pressures were recorded in the anterior and posterior segments of the acetabulum; the lowest pressures were constantly found at the zenith of the joint. The relationship of these findings to the pathogenesis of osteoarthritis is considered

1. Further consideration has been given to the lateral rotation which occurs at the ankle joint in uncorrected club feet. 2. Medial rotation osteotomy of the tibia may be used to restore more normal alignment to the hind foot at the expense of an increase in varus of the forefoot, which must be corrected at a second operation. 3. The early results in seven feet treated in this manner are reported. 4. We hope that this paper will be regarded more as a contribution to the understanding of the anatomy of uncorrected club foot than as advocacy of a new method of surgical treatment

Arthroscopy of the hip revealed a torn acetabular labrum in seven young patients. Three of them had had an acute onset of symptoms during sporting activities. On examination all seven patients had pain on passive flexion and medial rotation of the joint. All but one of the tears were located on the posterosuperior portion of the labrum, and, in the acute cases, vascular dilatation around the tear was observed. In these cases, repeated arthroscopy several months later showed that the vascular changes had disappeared, but the tear was still present. The aetiology, diagnosis and treatment of the torn acetabular labrum are discussed

We investigated the relationship between the pain experienced by 50 patients with osteoarthritis of the hip and the resting intra-articular pressure of the synovial fluid. We found a significant linear correlation between these factors, greater pain being experienced by patients with higher pressures. In 20 cases we showed that the pressure rises in extension and medial rotation and is least in flexion and mid-abduction. These results help to explain the benefits of rotation osteotomy of the hip and of psoas release. They also help explain the natural resting position of the hip in patients with an acute effusion and the fixed deformities associated with late osteoarthritis of the hip

Aims

Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinematics with their deep medial congruent fitting of the tibia to the femur almost like a ball-on-socket, and a flat lateral part. GMK Sphere is a novel MP implant. Our primary aim was to study the migration pattern of the tibial tray of this TKA.

1. Coracoid transplantation for recurring dislocation of the shoulder is described. 2. In my experience of over thirty cases only once has true dislocation recurred after this operation. Recurrence was due to avulsion of the bone block. 3. Failure to repair the original detachment of the glenoid labrum is a frequent cause of recurrence of dislocation of the shoulder. An explanation is offered for this failure; namely that the injured labrum adheres to the deep surface of the subscapularis muscle instead of reattaching itself to bone. This reinforces Watson-Jones's advice that the original dislocation should be treated by complete immobilisation in full medial rotation for three weeks

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes

From 1956 to 1965, congenital dislocation of the hip was treated in a standard manner in 191 cases. Reduction and plaster immobilisation was followed by a period in a Batchelor type plaster in full medial rotation. Femoral neck anteversion was then corrected by derotation osteotomy. In 95 children 117 hips were treated in this way and have been reviewed annually for 18 to 27 years. In 1983 they were assessed; there were 101 hips with good clinical results; radiologically, on a modified Severin scale, 62 were good, 39 were fair and 16 were poor. Derotation osteotomy proved to be the stimulus for growth of the acetabular roof in most cases; its safety, ease of performance and predictability suggest that it is superior to other methods of correcting the dysplasia

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

We report a retrospective study of 46 patients with continuing difficulties after anterior reconstruction of a shoulder for instability. In 31 patients instability was still present; in 12 of these, posterior or multidirectional instability had not been recognised and a further 11 had an uncorrected anatomical defect. In 20 patients with significant pain there was often more than one cause: impingement syndrome was seen in nine, osteoarthritis in seven, implant irritation in four and instability alone in two. A disabling medial rotation contracture was seen in 10 patients, four of whom had painful osteoarthritis. We conclude that recurrence of symptoms may imply that the direction of the instability was not recognised, that an anterior repair should not be too tight, and that pain after successful stabilisation is often due to impingement

1. The semilunar cartilages are part of the rotator mechanism of the knee joint. 2. Movement of the weight-bearing knee comprises synchronous lateral rotation of the tibia with extension and medial rotation of the tibia with flexion. 3. When this synchrony is disturbed, injuries to the semilunar cartilages result. 4. Damage to the anterior two-thirds of the medial cartilage blocks lateral rotation of the tibia, with consequent physical signs that are pathognomonic of the retracted and the bowstring cartilage, which are the most common types of injury. 5. Each type of cartilage injury produces its own pattern of erosion of articular cartilage and its own sequence of symptoms as so-called arthritis develops. 6. The sequence of symptoms may be halted and often reversed by removal of the torn cartilage. Operation is warranted in most cases however long the history and whatever the age of the patient. 7. The development of medial retropatellar arthritis is explained. The symptoms are often relieved by removal of the medial semilunar cartilage and adequate post-operative rehabilitation

Aims

The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective.

1. One hundred and seventy-three hips in 138 patients have been examined and studied in reference to the type of treatment received. 2. Shepherd's method of assessing the results of arthroplasty operations has been adapted to this series. 3. Satisfactory results were found in 77·9 per cent of all patients. 4. The value of straight longitudinal traction is questioned. Medial rotation appears to be an essential step in the reduction of the deformity. 5. Manipulation was found to be a relatively safe and effective method of reducing the deformity in patients seen soon after an acute episode, and should be reserved for them. 6. Complications were common after nailing operations, and included subtrochanteric fracture in three cases. 7. Avascular necrosis was the commonest cause of a poor result. The two types of avascular necrosis are discussed. 8. Avascular necrosis was found in 37 per cent of cases in which a manipulation was followed by a nailing operation. 9. Avascular necrosis was not found in any case in which a manipulation was combined with the use of Moore's pins, but such cases were kept under observation for a shorter time. 10. Avascular necrosis was found in 38·1 per cent of cases of cervical osteotomy

1 . Twenty-one cases of poliomyelitis and twenty cases of brachial plexus injury in which muscle transplantations had been performed to restore elbow flexion have been reviewed. The average follow-up period was four and a half years. 2. The results were graded objectively and subjectively. They were better when passive extension of the elbow was limited; such limitation always occurs after Steindler's operation, but infrequently after pectoral transplantation. 3. The results of pectoral transplantation are good when there is no significant shoulder paralysis; if there is shoulder weakness arthrodesis of the joint may be required to control medial rotation and adduction of the shoulder on flexion of the elbow. In brachial plexus lesions the results of pectoral transplantation may be marred by simultaneous contraction of the triceps. This can be overcome by transplanting triceps into the flexor apparatus. Triceps transplantation is rarely indicated because loss of active extension of the elbow is a grave disability. 4. Subjective results tended to be worse than objective results in brachial plexus lesions because impairment of sensibility in the hand often limited the usefulness of the limb. In striking contrast the subjective results were in general far better than the objective in patients who had had poliomyelitis. In them the smallest gain can be of functional value

1. The synovial membrane and capsule in osteoarthritis of the hip have been studied in twenty-five cases. Dissections have been made on fresh cadavers to establish the normal structure and function of these tissues at different ages. 2. Fragments of bone and cartilage were found beneath the synovial surface in twenty-three cases of the twenty-five cases of osteoarthritis. 3. The source of these fragments is the degenerate articular surfaces. 4. The fibrosis of the synovial membrane and capsule follows the synovial hyperplasia which accompanies the phagocytosis of these fragments. 5. A similar histological picture has been produced by injecting fragmented cartilage into the knee joints of rabbits. The injected fragments are found beneath the surface, and synovial hyperplasia is followed by subsynovial fibrosis. 6. The greatest amount of this joint debris is found in the lowest part of the joint cavity. 7. The joint capsule is particularly sensitive to traction. 8. All parts of the capsule are tight in extension, which is the weight-bearing position. 9. Fibrotic shortening of the capsule in the lowest part of the joint cavity explains many of the symptoms and signs of the disease: pain is caused by an attempt to stretch the capsule; muscle spasm occurs in the muscles supplied by the sensory nerves of this part of the capsule; extension, medial rotation and abduction, which tighten this area, are lost first; progressive shortening causes deformity in the opposite direction, namely flexion, lateral rotation and adduction; the loss of extension causes a more rapid wearing of articular cartilage on weight bearing; subperiosteal new bone is formed on the under-surface of the neck of the femur. 10. The symptomatology is discussed

Aims

The extensive variation in axial rotation of tibial components can lead to coronal plane malalignment. We analyzed the change in coronal alignment induced by tray malrotation.

Aims

The removal of the cruciate ligaments in total knee arthroplasty (TKA) has been suggested as a potential contributing factor to patient dissatisfaction, due to alteration of the in vivo biomechanics of the knee. Bicruciate retaining (BCR) TKA allows the preservation of the cruciate ligaments, thus offering the potential to reproduce healthy kinematics. The aim of this study was to compare in vivo kinematics between the operated and contralateral knee in patients who have undergone TKA with a contemporary BCR design.

A cadaver study was performed to determine the effect of arm position and capsular release on rotator cuff repair. Artificial defects were made in the rotator cuff to include only the supraspinatus (small) or both supraspinatus and infraspinatus (large). The defects were repaired in a standard manner with the shoulder abducted 30 degrees at the glenohumeral joint. Strain gauges were placed on the lateral cortex of the greater tuberosity and measurements were recorded in 36 different combinations of abduction, flexion/extension, and medial/lateral rotation. Readings were obtained before and after capsular release. With small tears, tension in the repair increased significantly with movement from 30 degrees to 15 degrees of abduction (p < 0.01) but was minimally affected by changes in flexion or rotation. Capsular release significantly reduced the force (p < 0.01) at 0 degree and 15 degrees abduction. For large tears, abduction of 30 degrees or more with lateral rotation and extension consistently produced the lowest values. Capsular release resulted in 30% less force at 0 degree abduction (p < 0.05)

Aims

The morphometry of the distal femur was largely studied to improve bone-implant fit in total knee arthroplasty (TKA), but little is known about the asymmetry of the posterior condyles. This study aimed to investigate the dimensions of the posterior condyles and the influence of externally rotating the femoral component on potential prosthetic overhang or under-coverage.