We report the case of a child with cerebral palsy and spastic diplegia treated for bilateral fixed flexion of the knee by bilateral hamstring lengthening. An attempt to straighten the legs from 90 degrees to 20 degrees flexion damaged the sciatic nerve. There are no objective means of estimating how much deformity can be reduced safely. We present a method of calculating the extra strain in the sciatic nerve produced by reducing a flexion deformity. The result, combined with clinical judgement, provides guidelines for safe corrective surgery

Twenty patients with an average age of eighteen and a half years sustained osteochondral fractures of the lateral femoral condyle as the result of a sudden twist and valgus strain to the straight or almost straight knee. All the patients felt sudden pain at the moment of injury, all had a haemarthrosis, and yet the fracture escaped early diagnosis in one-third of the cases. Internal fixation of the fragment with early mobilisation is recommended if the diagnosis is made within two weeks of injury, and excision of the fragment if it is only later identified

1. Strain or rupture of the anterior marginal attachments of the meniscus was observed in approximately 10 per cent of a group of patients operated upon for internal derangement. 2. In about half of these a tear of the body of the meniscus was found and it is probable that this tear may have been the cause of the symptoms. In the remainder no injury to the body of the meniscus was found. 3. Recognition may be difficult and delay in diagnosis may be the cause of degenerative joint changes. 4. The condition should be looked for at operation when the meniscus appears to be intact or when the only lesion appears to be an area of chondromalacia on the weight-bearing surface of the femoral condyle

Resistance to infection may be influenced by foreign bodies such as devices for fracture fixation. It is known that stainless steel and commercially-pure titanium have different biocompatibilities. We have investigated susceptibility to infection after a local bacterial challenge using standard 2.0 dynamic compression plates of either stainless steel or titanium in rabbit tibiae. After the wounds had been closed, various concentrations of a strain of Staphylococcus aureus were inoculated percutaneously. Under otherwise identical experimental conditions the rate of infection for steel plates (75%) was significantly higher than that for titanium plates (35%) (p < 0.05)

1. Isolated dislocation of the radius at the elbow occurs most commonly as a pronation injury, associated with slight elbow flexion and a varus strain. Disruption of the radio-ulnar articulation occurs primarily because of tearing of the annular ligament, which is the most important reinforcing structure of this joint. The tensing of the interosseous membrane through neutral into supination, and consequently the approximation of the radius to ulna, supports the recognised supination manoeuvre to reduce such an injury. 2. It is suggested that this injury may be more common than previously appreciated. It may be not diagnosed, it may be over-diagnosed as total dislocation of the elbow, or it may be belatedly diagnosed as a congenital dislocation of the radial head

1. Thirteen cases of fracture of the lateral process of the talus seen over a period of thirteen months are reported. 2. The mechanism of the injury would appear to be inversion strain of the foot with dorsiflexion of the ankle. 3. The diagnosis would no doubt be made more often if the possibility of this fracture were kept in mind, and if radiographs of good quality were taken with the ankle at 0 degree and the leg rotated inwards 10 to 20 degrees. 4. With regard to treatment, early operation appears to give good results, a single large fragment being reduced accurately and small or comminuted fragments being removed

Any operation involving the implantation of a foreign body increases the risk of infection. The implant material and its surface, the dead space, and any necrosis or vascular changes play a significant role in susceptibility to infection. We investigated the effect of the dead space in an intramedullary nail on the rate of local infection. We inoculated the intramedullary cavities of rabbit tibiae with various concentrations of a human pathogen, of Staphylococcus aureus strain, and then inserted either a solid or a hollow slotted stainless-steel nail. We found a significantly higher rate of infection after use of the slotted nail (59%) than after the solid nail (27%) (p < 0.05)

We used 15 pairs of femora from fresh human cadavers to study the effects of the size and location of the entry hole for an intramedullary nail on the strength of the femur. Right femora were used as controls. Left femora in group 1 had a 10 mm entry hole in the 'ideal' location in the piriformis fossa. Group 2 had a 14 mm entry hole in the same position and group 3 had a 14 mm entry hole anterior to this on the superior aspect of the femoral neck. Femora were equipped with strain gauges and loaded to failure in compression. There was reduced stiffness and load to failure in group 3 specimens, suggesting that the location of the hole was more important than its size

1. An experimental study of the healing mechanism in circumscribed defects in femora of albino rats of the Wistar strain is described. 2. Only the outer one-fifth of the defect is repaired by subperiosteal bony callus, the rest of the defect being repaired by endosteal callus. 3. Subperiosteal callus does not bridge the defect until endosteal callus is developed fully. 4. As peripheral callus matures the greater part of the endosteal callus is resorbed, with the exception of trabeculae attached to the margin of the defect. 5. The resorbed area in the medullary part of the defect is gradually obliterated by deposition of inner circumferential lamellae. 6. There appear to be differences between the mechanism responsible for repair of fractures of a long bone and that which heals circumscribed bone defects

We measured the stability of fixation in femoral neck fractures treated with von Bahr screws, investigated the influence of impaction and correlated peroperative stability with the clinical results. Stability was measured at operation using a metal probe fitted with strain gauges. Its tip was anchored in the subchondral bone of the femoral head and its lateral end was fixed in the lateral femoral cortex. The shearing force produced by longitudinal compression applied to the foot of the operated leg was recorded. The results in 41 consecutive patients all followed for 30 months, showed that fractures with early loosening or nonunion had all had significantly poorer stability than the fractures that had healed. Impaction improved stability in only 23 out of the 41 fractures; in the others stability had deteriorated or was unchanged

1. Pain in the elbow in javelin throwers is a common complaint. 2. The commonest type is caused by recurrent strain of the medial ligament. It develops in individuals who employ an incorrect throwing technique. The symptoms are cumulative, increasing with throwing and decreasing and resolving with rest. Treatment consists in improving the throwing technique. Local anaesthetic injected into the tender area produces complete but temporary relief. Hydrocortisone may produce partial or complete relief. 3. A second type of "javelin elbow" occurs in expert throwers and is the result of hyperextension of the elbow at the end of the throw, causing an injury to the tip of the olecranon. The symptoms are the result of a single throw or "mal-throw" and are completely disabling. They resolve with rest but tend to recur. If the tip of the olecranon is fractured excision of the fragment completely relieves the symptoms

Aims

Few risk factors for rotator cuff disease (RCD) and corresponding treatment have been firmly established. The aim of this study was to evaluate the relationship between numerous risk factors and the incidence of surgery for RCD in a large cohort.

Objectives

The ability to determine human bone stiffness is of clinical relevance in many fields, including bone quality assessment and orthopaedic prosthesis design. Stiffness can be measured using compression testing, an experimental technique commonly used to test bone specimens in vitro. This systematic review aims to determine how best to perform compression testing of human bone.

At the time of publication sixty-three additional patients have been fitted with the patellar tendon bearing prosthesis. Twenty of these were new amputees, and forty-three were old amputees who had previously worn a conventional limb. Of this group, nine were considered failures. The contra-indications for fitting now include: 1) coincident knee derangement such as cruciate or collateral ligament laxity (the trauma that causes the amputation often produces knee injuries as well; in this event the side irons of the conventional prosthesis help to support the knee); 2) scars in the popliteal fossa, such as those produced by exploration of the popliteal vessels; 3) marked variation in stump size such as in rapidly growing children or obese people; and 4) labourers obliged to work on rough ground, which places additional strain on the knee

One hundred normal fingers were dissected and arthrographs obtained by injection of a chromopaquegelatin mixture, allowing comparison between the radiographic and macroscopic configuration of the synovial capsule. Synovial recesses protruding from each side of every metacarpo-phalangeal joint were found in relation to the collateral ligaments and corresponding exactly with the site of radiological erosions. A group of bursae lying on the superficial aspect of collateral ligaments were also demonstrated. A rudimentary infra-articular meniscus was found. The results of examination of the insertions of the interossei showed differences from traditional descriptions. The cause of rheumatoid deformity was suggested to be the rheumatoid process arising in the lateral recesses and lateral bursae, weakening the collateral ligaments, which give way in the directions of the deforming forces. These are derived from the long flexor tendons, which were shown to exert an ulnar and volar strain on the metacarpo-phalangeal joint of every finger during grip

1. The duration of Legg-Perthes' disease seems somewhat shortened by abduction weightbearing plaster treatnlent. The average age of onset of our sixty patients at the start of this treatment was seven years nine months. The patients were treated in abduction plasters for an average of nineteen months. 2. The contour of the femoral head in relation to the acetabulum is better preserved than after our previous methods of treatment. We have evaluated our cases by the method of Mose, by the epiphysial index of Eyre-Brook and the epiphysial quotient of Sjovall, and by the centre/edge angle of Wiberg. 3. There was no undue influence on the growing epiphysis and no evidence of ligamentous strain. 4. With this type of protected weight-bearing, the patients were kept active when both hips were affected. 5. No patient with unilateral disease showed Legg-Perthes' changes on the opposite side while under treatment or at follow-up. 6. The children were able to be at home and to attend school

1. There seem to be two distinct methods of destruction of the foot, once pain sensibility has been lost: the first is a slow erosion and shortening associated with perforating ulcers under the distal weight-bearing end of the foot. The second is a proximal disintegration of the tarsus in which mechanical forces often determine onset and progress of the condition. 2. Once the tarsus begins to disintegrate it is difficult to halt the rapid destruction of the foot. 3. It is possible to detect early stages of this condition in time to take preventive measures. Routine palpation of anaesthetic feet will reveal patches of warmth localised to bones and joints which are in a condition of strain. Radiographs of such feet and a study of posture and gait may define early changes which point to one of several possible patterns of disintegration which may follow. 4. These patterns are described and discussed and suggestions made for preventive and corrective measures

1. Recurrence of deformity after operations for drop foot is often associated with opening of the front of the ankle joint: this has previously been regarded as a complication of the operation. 2. This study of sixty paralytic drop feet treated conservatively reveals that this laxity was in fact present in no less than 43 per cent. 3. The laxity is most commonly found when the calf muscle is strong and it can occur within a year of the onset of the paralysis. It is not always prevented by wearing a toe-raising spring. 4. Such anterior laxity may well be a common cause of failure of many of the standard operations for drop foot. 5. Before operation for drop foot is undertaken a lateral radiograph of the ankle should be taken in forced plantar-flexiori. If this demonstrates anterior laxity any standard operation is unlikely to succeed unless the anterior fibres of the collateral ligaments are protected from strain by simultaneous tendon transplantation or unless the ankle is included in the arthrodesis

1. If a vertical load is applied to the head of the femur parallel to its shaft, the upper cortex is stretched and the lower cortex is compressed. The neck breaks from the upper subcapital border to the lesser trochanter. This type of fracture is rarely found clinically. 2. If a compressive force is applied to the area between head and greater trochanter while the head is loaded vertically, a transverse fracture of clinical appearance is produced. If this axial pressure acts along the part of the neck above the central axis a subcapital comminuted fracture results. If the pressure acts below the central axis the result is a transcervical fracture. 3. Strain gauge experiments have shown that axial compression within the upper segment of the neck is produced by the abductor muscles of the hip. Adductor muscles produce a low axial compression. It is suggested that muscular action at the time of injury influences the type of fracture produced by the injury