The anterior cruciate ligament was replaced in rabbits, using implants of carbon or polyester filaments with known mechanical properties. The biocompatibility of the implants was assessed in detail using light microscopy, and scanning and transmission electron microscopy. Mechanical tests were made of stability, in comparison with normal joints and controls after excision of the ligament. Some carbon fibre implants broke down in vivo, allowing instability; the fragments caused chronic inflammation. Intact carbon implants did not induce the formation of neoligaments; they were covered by tissue, but there was no ingrowth. Polyester did not degrade mechanically and supported early collagenous ingrowth within the implant, even in the mid-joint space. It was concluded that there was no justification for the use of carbon fibres as anterior cruciate replacements; polyester appeared to be suitable

We have reviewed 42 of 52 consecutive patients at an average of 14 years after a tenodesis based on Evans' operation performed for chronic lateral instability of the ankle. Only 21 patients (50%) had satisfactory long-term functional results, and 12 patients with satisfactory early results had deteriorated after three to six years. Stress radiographs were used to measure anterior talar translation and talar tilt, and a good correlation was found between function and mechanical stability. Talar tilt had been controlled more successfully than anterior translation. Marginal osteophytes were found in most ankles, and were larger and more numerous in those with the greatest instability

The role of atmospheric pressure in providing static stability of the shoulder was studied experimentally in 24 cadaveric shoulders. Atmospheric air was allowed to enter the joint after puncturing the capsule. Three types of experiment were performed: in the first, the capsule was punctured after sequential division of the muscles; in the second, atmospheric air was let in by percutaneous puncture of of the capsule without dividing the muscles; and in the third, air was first let into the joint by percutaneous puncture of the capsule and then the muscles of the shoulder were divided. It was found that the intact shoulder subluxated after percutaneous puncture even without division of the overlying muscles or the capsule. Our findings suggest that negative pressure and muscle tone are the main static stabilisers of the shoulder, rather than the joint capsule

Eleven patients with metastases in the cervical spine had operations for severe pain due to a pathological fracture which, in eight of the cases, was unstable. Conservative treatment had either failed or was unsuitable. In the first five patients internal fixation with tension band wires and bone grafts was supported by a halo-brace. The method has evolved to the use of posterior instrumentation with laminar wires from two levels above the lesion to two levels below. Stability is increased by the use of bone cement with or without bone autografts applied to one side of the spine. This technique enables the patient to get up within a few days of operation--a great advantage when life expectancy is limited. The operations were successful in all except one case

We treated 120 children between the ages of 12 and 31 months with 137 developmental dislocations of the hip and reviewed them at a mean follow-up of 14 years. We had used two-directional arthrography of all hips before reduction to evaluate the anterior, superior, and posterior portions of the limbus. Of the 137 hips, 64 had no interposed limbus in the AP view of the arthrogram, but 45 of these had an interposed anterior or posterior portion of the limbus. The hips with good stability and no interposed limbus in either AP or lateral arthrograms had excellent results by closed methods; in the other cases the results were less satisfactory. Our findings suggest that hips suitable for management by closed reduction can be identified by two-directional arthrography. Hips shown to have an interposed limbus are best managed by open reduction

1. The results have been reviewed of forty-two traumatic dislocations of the knee in forty-one patients, twenty-six of which were treated conservatively. 2. Primary operative repair was carried out in only three cases, although a further ten had operative intervention for various complications. 3. It was not possible to compare the results of operation with those of conservative treatment, because the operative procedures were so diverse in nature. 4. The conservative treatment of twenty-six dislocations yielded surprisingly good results with regard to stability, absence of pain, and range of flexion movement. 5. In general, immobilisation for long periods, like operative repair, led to reduced movement. 6. In the absence of complications, conservative treatment is the method of choice

1. A concept and design of polycentric knee arthroplasty based on the biomechanics of normal knee movement is presented. The diseased articular surfaces of the femoral condyles and tibial plateaus are replaced separately by prosthetic implants secured with cement. The collateral and cruciate ligaments are retained to maintain joint stability. 2. The early results from this arthroplasty in twenty-two knees are assessed. The operation gave relief of pain in twenty-two, a range of movement greater than 90 degrees in thirteen, no lateral instability in sixteen of twenty-two knees and an increased degree of mobility for nineteen of twenty individuals (two bilateral arthroplasties). 3. Operative complications consisted of delayed wound healing in four knees and common peroneal nerve palsy in one. One knee was subsequently arthrodesed for lack of functional improvement

1. Grafts of joint cartilage from immature lambs were used to repair articular cartilage defects in other lambs and in adult sheep. 2. Stability of these grafts in a functional state was found in most for periods up to fourteen months. Although a limited homograft reaction occurred this did not lead to destruction of the cartilage, even though parts of it were well vascularised. 3. The results suggest that the process of endochondral ossification is associated with the liberation of antigenic material leading to sensitisation of the host. Destruction ofthe cartilage is prevented by an inhibitory action which the matrix appears to exert on the destructive elements themselves and which is itself dependent on the vitality of the chondrocytes. 4. The avascularity of cartilage is not a sufficient explanation for its privileged position in relation to the homograft reaction

1. Twenty-two dislocations of the hip occurring in patients paralysed from an early age have been studied. All showed abnormal coxa valga. The coxa valga, which may gradually reach 180 degrees, precedes dislocation and makes it inevitable. The presence of unbalanced adductor power may hasten dislocation, but the latter can occur in complete flaccid paralysis. 2. The combination of structural instability of the hip joint and muscular weakness may make independent walking impossible, but restoration of stability gives considerable improvement in any remaining muscular power and may alter the patient's whole future. 3. A method of correcting the basic deformity of coxa valga by osteotomy is described and the results of nine operations are reviewed

Aims

The classical longitudinal incision used for the direct anterior approach (DAA) to the hip does not follow the tension lines of the skin and can lead to impaired wound healing and poor cosmesis. The purpose of this retrospective study was to determine the satisfaction with the scar, and functional and radiographic outcomes comparing the classic longitudinal incision with a modified skin crease ‘bikini’ when the DAA is used for total hip arthroplasty (THA).

The Norway elbow prosthesis is a non-constrained cemented total replacement. It depends on intact collateral ligaments for stability, and allows a full range of movement. The system includes several sizes of components, all freely interchangeable, and semi-constraint can be provided by a locking ring if damaged collateral ligaments make dislocation possible. The prosthesis has been used in more than 350 elbows in Norway and the detailed results for 118 elbows studied prospectively since 1987 are reported. It is inserted through a posterolateral triceps-splitting incision with minimal muscle disruption and bone resection, preserving the collateral ligaments. The results as regards pain relief and range of movement were comparable with those of other elbow prostheses, but there were fewer serious complications. At a mean follow-up of 4.3 years, the failure rate was 3.4%

Aims

This study presents the long-term survivorship, risk factors for prosthesis survival, and an assessment of the long-term effects of changes in surgical technique in a large series of patients treated by metal-on-metal (MoM) hip resurfacing arthroplasty (HRA).

The rigidity of a sliding compression screw and three cannulated lag screws in the treatment of subcapital fractures was compared in five pairs of female cadaver femora. There were no significant differences between the compressive strength, bone density, cortical thickness or Singh index of the bones in each pair. A subcapital fracture was standardised using a perpendicular saw cut across the femoral neck. A uniaxial 'load test system' with force and length measurement facilities was used to mimic cyclical stressing applied in vivo at a frequency of 0.5 Hz from 0 to 3 times body-weight. There was no significant difference between the fixation afforded by the sliding compression screw and three lag screws. Bone quality was the single most important factor in the stability of the bone implant unit

We report the use of a free tendon graft in 70 patients to repair lesions of the capsuloligamentous complex of the metacarpophalangeal joint of the thumb. Of these 37 had a lesion of the ulnar collateral ligament, 18 of the radial collateral and 11 of the volar plate. Four patients had combined lesions. We outline our techniques and review 51 of the patients. Of those 47 (92%) were satisfied, and all but one had regained full stability. Pinch grip strength was normal in 48. About one-third of the patients had some loss of flexion/extension; this was seldom noticed by the patients and caused no significant disability. Free tendon graft reconstruction is indicated for severe fresh lesions, for old lesions with chronic disability and for lesions which have not responded to conservative management

Sixty-three knees with chronic ligamentous instability treated with flexible carbon fibre are reviewed. Assessment was by pre-operative and postoperative grading of function in work and sport, together with a subjective evaluation of the result based on stability. Fifteen knees had collateral repairs, seven had cruciate repairs and 41 had combined collateral and cruciate repairs. Overall, 71% of knees showed improvement in function and 67% had good or excellent results subjectively. Clinical examination did not correlate well with the patient's evaluation of the result. Nineteen unselected cases with intra-articular (cruciate) carbon fibre had arthroscopies. Infiltration of collagen tissues into the cruciate replacement was a slower process than at the extra-articular (collateral) site. There was no clinical or macroscopic evidence of synovitis but microscopically there was evidence of synovial irritation

In a series of seventeen patients with unilateral osteoarthritis of the hip a scintiscanning follow-up study was made before and after total hip replacement for the assessment of the normal course of the 87mSr-scintiscan. In another series of twenty-eight patients with total hip replacement a photoscan was made as a supplement for the diagnosis of loosening of one or both components of a total hip implant. In most of these cases it proved to be a useful method, especially when clinical and raidological examination was inconclusive. It is concluded that up to six months after operation increased osteoblastic activity exists; the scintiscan became normal after that time. 87mSr scintiscanning offers a safe and simple technique for the assessment of the success and stability of total hip arthroplasty. It is also a useful aid for the early detection of loosening and infection. The procedure can help in the differential diagnosis of complaints after total hip replacement

The results of 110 operations for the treatment of fractures through metastases in the femoral neck and intertrochanteric region have been studied. Of these, forty-four fractures were treated by internal fixation, forty-six by resection of the femoral head and neck, and twenty by prosthetic replacement. The following conclusions were reached. 1. Prosthetic replacement of the femoral head is a reliable procedure. 2. The long stem type of prosthesis has the advantages of greater stability and simultaneous fixation of the shaft. 3. Patients with diffuse metastatic disease of the ilium are not suitable for prosthetic replacement. These patients should be treated by resection of the femoral head and neck. 4. Resection is a less traumatic procedure and therefore useful in the palliative treatment of patients in poor general condition. 5. Internal fixation leads more often to complications and unfavourable results than do the other methods

We reviewed our experience with a modified triple innominate osteotomy for hip instability and limb shortening due to poliomyelitis in 62 adolescent and adult patients, treated from 1973 to 1990. Their ages at surgery ranged from 12 years to 35 years (average 22.3). At a mean follow-up of 4 years (2 to 18) 59 of the patients (95.2%) had substantial improvement in hip stability, and all but one had radiological improvement as determined by the acetabular angle, centre-edge angle and acetabulum-head quotient. In 59 cases in which transiliac limb lengthening was attempted, the mean gain was 1.7 cm (0.6 to 3.0). When the abductor muscles had been partially paralysed, the operation produced an appreciable increase in power in 12 of the 39 hips examined

Biological fixation of cementless femoral implants requires primary stability by optimal fit in the proximal femur. The anatomy of the bone must then be known precisely. We analysed in vitro the accuracy of bone measurements of 32 femurs and compared the dimensions obtained from radiographs and CT scans with the true anatomical dimensions. Standard radiographs gave only a rough approximation of femoral geometry (mean difference: 2.4 +/- 1.4 mm) insufficiently accurate to allow selection of the best fitting prosthesis from a range of sizes and altogether inadequate to design a custom-made prosthesis. CT scans give greater accuracy (mean difference: 0.8 +/- 0.7 mm) in our experimental conditions, but in clinical practice additional sources of error exist

We assessed proprioception in the knee using the angle reproduction test in 20 healthy volunteers, ten patients with acute anterior instability and 20 patients with chronic anterior instability after reconstruction of the anterior cruciate ligament (ACL). In addition, the Lysholm-knee score, ligament laxity and patient satisfaction were determined. Acute trauma causes extensive damage to proprioception which is not restored by rehabilitation alone. Three months after operation, there remained a slight decrease in proprioception compared with the preoperative recordings, but six months after reconstruction, restoration of proprioception was seen near full extension and full flexion. In the mid-range position, proprioception was not restored. At follow-up, 3.7 ± 0.3 years after reconstruction, there was further improvement of proprioception in the mid-range position. There was no difference between open and arthroscopic techniques. The highest correlation was found between proprioception and patient satisfaction. After reconstruction of the ACL reduced proprioception may explain the poor functional outcome in some patients, despite restoration of mechanical stability