We describe 74 patients with disabling instability of the knee due to isolated anterior cruciate deficiency. None responded to conservative measures or correction of internal derangements. All patients were treated by replacement of the anterior cruciate ligament with the medial third of the patellar tendon as a free graft, supplemented by an extra-articular MacIntosh lateral reconstruction. A satisfactory outcome was found in 93% of knees after an average of 70 months follow-up. Cast immobilisation after operation, the interval between injury and reconstruction, the age of the patient and the severity of symptoms before reconstruction had no significant effect on the final outcome.

In a series of 64 ligamentous injuries of the knee, 33 were explored through a medial incision and 31 through a long lateral incision. Sensibility of the skin, the occurrence of neuromas, and discomfort during kneeling were evaluated three and six years postoperatively. The lateral incisions produced less dysaesthesia, fewer neuromas and less discomfort on kneeling.

We report the two- to four-year results following the insertion of the Leeds-Keio prosthetic ligament for chronic anterior cruciate deficiency. Virtually all the 20 patients were less disabled by instability, but objective results were good or excellent in only two-thirds and under anaesthesia the pivot shift sign was still positive in half. Arthroscopic and histological assessment in 16 patients failed to show the development of a functional neoligament, and the common appearance of a synovitic reaction to polyester particles gave concern.

The nerve roots of the cauda equina may be visualised by contrast-enhanced CT scans and by surface-coil MRI. We have identified the pattern of anatomy from L2-L3 to L5-S1 in 10 human cadaver specimens and correlated this with anatomical dissections. Individual roots are slightly more distinct on contrast-enhanced CT than on surface-coil MRI. There is a crescentic oblique pattern of nerve roots at the lower lumbar levels which is still apparent in the more crowded proximal sections. In all cases, the axial images correlated precisely with the dissections. Current imaging modalities can help the clinical understanding and management of abnormalities in this region of the spine.

Little has been published about the Krukenberg operation, which has been regarded as primarily indicated for the blind patient with bilateral hand amputations. Of the 35 Krukenberg cineplasty operations I have performed in the last 36 years, only two have been on blind patients. The operation provides forearm amputees with pincers which allow them to perform tasks without a prosthesis, but does not preclude the use of any type of aid. The author's operative procedure is described and the results illustrate its practical application for most patients.

Traumatic rupture of the tendon of the subscapularis muscle was documented as an isolated lesion in the shoulders of 16 men. The injury was caused either by forceful hyperextension or external rotation of the adducted arm. The patients complained of anterior shoulder pain and weakness of the arm when it was used above and below the shoulder level. They did not experience shoulder instability. The injured shoulders exhibited increased external rotation and decreased strength of internal rotation. A simple clinical manoeuvre called the 'lift-off test', reliably diagnosed or excluded clinically relevant rupture of the subscapularis tendon. Confirmation of the clinical diagnosis was best achieved by ultrasonography or MRI, but arthrography or CT arthrography were also useful. Surgical exploration confirmed the diagnosis in every case. Repair of the ruptured tendon was technically demanding and required good exposure to identify and protect the axillary nerve.

Subacromial decompression was performed arthroscopically on 65 patients who were evaluated two to five years after the procedure. None had full thickness rotator cuff tears. Patients with partial thickness cuff tears were included in this study in order to allow comparison of arthroscopic acromioplasty with open acromioplasty for stage II impingement. On the UCLA shoulder rating scale, 89% of the cases in this study achieved a satisfactory result. These results compare favourably with those reported following open acromioplasty. The arthroscopic procedure is technically demanding. When properly performed in patients with appropriate indications, hospitalisation is brief, return to activities is rapid, there is little risk of deltoid muscle complications, and the results are lasting.

We examined biopsy specimens obtained during surgery on 115 patients with complete rotator cuff rupture. The vascularised connective tissue covering the area of rupture and the proliferating cells in the fragmented tendons reflected more of the features of repair than of degeneration and necrosis. The main source of this fibrovascular tissue was the wall of the subacromial bursa. These features clearly indicated a vigorous reparative response which might play an important role in tendon reconstitution and remodelling. We therefore suggest that extensive debridement along with subtotal bursectomy, commonly practised during surgical repair of rotator cuff rupture, should be avoided. Although strong suture margins are essential for good operative results, debridement should be judicious and preserve as much as possible of the bursa and the associated fibrovascular tissue.

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).

One hundred and fifty asymptomatic shoulders in 75 schoolchildren were studied. The shoulders were tested for instability and a hyperextensometer was used to assess joint laxity. Signs of instability were found in 57% of the shoulders in boys and 48% in girls; the commonest sign was a positive posterior drawer test which was found in 63 shoulders. A positive sulcus sign was found in 17 shoulders and 17 subjects had signs of multidirectional instability. General joint laxity was not a feature of subjects whose shoulders had positive instability signs.

We reviewed 35 of 38 consecutive patients who had operative treatment for medial epicondylitis of the elbow after the failure of conservative management. Their mean age was 43 years and mean follow-up was 85 months. At operation residual tears with incomplete healing were consistently found in the flexor origin at the medial epicondyle and microscopy showed reactive fibrous connective tissue with varying degrees of inflammation. The mean subjective estimate of elbow function was improved from 38% to 98% of normal, while isokinetic and grip strength testing in 16 patients showed no significant difference from the unoperated elbow. Results were excellent in 25 cases, good in nine and fair in one; 86% of the patients had no limitation in the use of the elbow.

A case of osteogenesis imperfecta, presenting with bowed deformity of both forearm bones and dislocation of the radial head was treated by separate elongation of both bones using Ilizarov's external fixator.

The incidence of refracture following the removal of screws and plates from the diaphyses of 115 forearm bones in 80 patients has been studied. Refracture occurred in four adult patients as a result of minimal trauma, in two patients at the original fracture site after premature plate removal, at the site of a countersunk interfragmentary screw in one and at the original fracture site in another who had required three operative procedures to achieve 'union'. It is suggested that refracture could have been avoided in at least two of these patients. If the 3.5 mm plating system has been used, the incidence of refracture should be minimal.

Enoxaparin, a low-molecular-weight heparin, has been used together with spinal or general anaesthesia in a prospective, randomised study of 188 consecutive elective hip replacements. Bilateral venography was performed on all patients on day 13 after operation. Group I (65 patients) received spinal anaesthesia and no immediate injection of enoxaparin. Group II (61 patients) received spinal anaesthesia and 20 mg of enoxaparin one hour after the onset of anaesthesia. Group III (62 patients) was operated on under general anaesthesia and received 40 mg of enoxaparin 12 hours prior to surgery. This group acted as the control group. In all three groups, 40 mg of enoxaparin was given 12 hours after the end of surgery and continued on a once-daily basis. Proximal DVT occurred in 6% of group I, 6.7% of group II and 6.5% of group III, not a significant difference. Distal DVT was present in 11% of group I, 5% of group II and 0% of group III; this was a highly significant difference (p = 0.007). Tolerance was good and the incidence of bleeding low in the three groups. Our results confirm the low rate of DVT in patients operated on under general anaesthesia with the standard procedure of 40 mg of enoxaparin on a once-daily basis started pre-operatively. The 40 mg-dose is also safe and effective in association with spinal anaesthesia if half the dose (20 mg) is injected an hour after the lumbar puncture.

The acetabular rim syndrome is a pathological entity which we illustrate by reference to 29 cases. The syndrome is a precursor of osteoarthritis of the hip secondary to acetabular dysplasia. The symptoms are pain and impaired function. All our cases were treated by operation which consisted in most instances of re-orientation of the acetabulum by peri-acetabular osteotomy and arthrotomy of the hip. In all cases, the limbus was found to be detached from the bony rim of the acetabulum. In several instances there was a separated bone fragment, or 'os acetabuli' as well. In acetabular dysplasia, the acetabular rim is subject to abnormal stress which may cause the limbus to rupture, and a fragment of bone to separate from the adjacent bone margin. Dysplastic acetabuli may be classified into two radiological types. In type I there is an incongruent shallow acetabulum. In type II the acetabulum is congruent but the coverage of the femoral head is deficient.

Total arthroplasty was performed on 21 congenitally dislocated hips in 18 women. In all cases the femoral head was dislocated cranially at least one-fifth of the height of the pelvis. The components were both cemented, the acetabulum being replaced to its original position. The acetabular roof was reconstructed by bone graft in 13 hips, and trochanteric osteotomy was done in 18 hips. The patients were assessed at a median follow-up time of 7.5 years when their median age was 54 years. Nine patients had been revised or required revision. At follow-up the average functional score (according to Charnley) was 6 for pain, 4 for walking ability and 5 for range of motion. The Harris hip score was 82. The patients' subjective evaluation of their satisfaction with the late results on a visual analogue scale was 93, range 23 to 100. The high loosening rate in such patients demands regular follow-up and preparedness for revision surgery.

In a double-blind, randomised study of thromboprophylaxis in patients undergoing total hip replacement, we compared a low-molecular-weight heparin with a placebo. Of the 120 patients enrolled, 112 completed the trial; 58 in the treatment group and 54 in the placebo group. Nine (16%) patients in the treatment group and 19 (35%) in the placebo group developed deep venous thrombosis, diagnosed by the 125I-fibrinogen uptake test (p < 0.02). Verification was obtained by phlebography in 86% of the patients. Prolonged surgery increased the risk of thrombosis in the placebo group but not in the treatment group (p < 0.05). There were significantly more cases of deep venous thrombosis in the placebo group during the first four postoperative days (p < 0.02). The groups did not differ with respect to peroperative and postoperative bleeding. Low-molecular-weight heparin offers safe and easily administered thromboprophylaxis in total hip replacement.

We have reviewed the results in 37 patients with unilateral congenital short femur (Pappas classes III to IX), treated by different lengthening procedures. The increase in the length of the femur varied from 15.6% to 142%, excellent or good results being obtained in 32 patients (86%). There was an average of 1.9 complications per case, most being seen earlier in the series when the Wagner technique was used. With the Orthofix and the Ilizarov techniques, we used callus distraction in all cases. We found that the proximal diaphysis of the congenitally abnormal femur healed less well, and we now prefer to perform corticotomy and callus distraction of the distal metaphysis. The Ilizarov method gave the best results, offering the possibilities of the simultaneous use of a Hoffmann fixator across the hip and the treatment of knee dislocation and instability.

Seventy-nine open tibial fractures were treated with unilateral uniplanar tubular external fixators. Excellent stability allowed early weight-bearing. All comminuted fractures, with or without bone loss, and some transverse or short oblique fractures with intermediate fragments were treated by early bone grafting through a posterolateral approach. The external fixator was dynamised as soon as periosteal callus was seen on the radiograph. Bone healing times ranged from 11 to 40 weeks (mean 20). Significant ankle stiffness occurred in 10.9% and leg shortening in 2.8%. Pin track infection was seen in 45.2% but was easily controlled with standard management. The external fixation frame allowed excellent functional freedom for Oriental patients to sit cross-legged and squat. Combined with early bone grafting, external fixation is an excellent method for the management of open tibial fractures.

We investigated 133 knees with suspected meniscal or cruciate injuries by magnetic resonance imaging, and compared the findings with those at arthroscopy. MRI was found to be highly sensitive, specific and accurate in the evaluation of the menisci and the anterior cruciate ligament.

Limb lengthening by means of distraction through the callus of a knee arthrodesis was performed in a 14-year-old boy with congenital hypoplasia of one lower limb. Knee arthrodesis was indicated because of destruction of the distal femoral epiphysis caused by a previous bone lengthening procedure.

Twenty-two knees with osteochondritis dissecans diagnosed before skeletal maturity were followed prospectively into middle age: 32% had radiographic evidence of moderate or severe osteoarthritis at an average follow-up of 33.6 years; only half had a good or excellent functional result. We found that osteoarthritis was more likely to occur if the defect was large or affected the lateral femoral condyle.

Of 54 patients with posterior dislocations of the hip of type I and type II (Stewart and Milford 1954), 47 were followed for a mean period of 6.7 years (2 to 11). Of these, 23 had dislocation with minimal lesions of the acetabulum (type I) and 24 had an avulsed dorsocranial fragment (type II). All were reduced by closed methods within six hours. The subsequent treatment of type I dislocations was conservative. At the beginning of the period type II injuries were treated conservatively, but surgery was increasingly chosen for later cases. Type I dislocations had significantly better results (p < 0.05) than type II fracture-dislocations, regardless of the method of treatment. There were no essential differences between the results of surgical and conservative treatment in type II dislocations.

We have reviewed 10 patients treated for anterior tarsal tunnel syndrome produced by compression of the deep peroneal nerve or its branches, and we have studied the anatomy of the tunnel in 25 adult feet. The causes of onset of the syndrome included contusion of the dorsum of the foot, tight shoe laces, talonavicular osteophytosis, ganglion, and pes cavus. The clinical signs were often diagnostic but electromyography was helpful. Operative decompression in nine feet of eight patients gave successful results at 1.5 to 4 years follow-up.

Between 1978 and 1988 a total of 27 operations were performed on 26 patients for cervical myelopathy due to rheumatoid disease in the subaxial spine. Three different causes were recognised: the first group had cord compression due to subluxation of the cervical spine itself (6 patients); the second had cord compression occurring from in front, with rheumatoid lesions of vertebral bodies or discs (6); the third had compression from behind the cord due to granulation tissue within the epidural space (14). Group I was treated by closed reduction of the subluxation followed by surgical fusion either from in front or behind. Group II was decompressed by subtotal resection of the involved vertebral bodies and discs, followed by interbody fusion. The patients in group III were decompressed by laminectomy and excision of fibrous granulation tissue from the epidural space. Good recovery of neurological function was observed after 18 of the operations, fair recovery after five, poor recovery followed three, and one was worse. Myelopathy recurred in four patients, all of whom had had anterior interbody fusion.

We reviewed two comparable groups of patients who had been treated for lumbar disc herniation by chymopapain chemonucleolysis (145) or conventional surgical discectomy (91). They were reviewed 10 years after treatment by questionnaire, followed by a personal interview by an independent observer. The results of the surgically treated groups were slightly better than those treated with chymopapain. In particular, there was significantly better early relief of leg and low back pain, and fewer patients needed a second procedure. Complications were few in both groups.

Since 1981, during operations for spinal deformity, we have routinely used electrophysiological monitoring of the spinal cord by the epidural measurement of somatosensory evoked potentials (SEPs) in response to stimulation of the posterior tibial nerve. We present the results in 1168 consecutive cases. Decreases in SEP amplitude of more than 50% occurred in 119 patients, of whom 32 had clinically detectable neurological changes postoperatively. In 35 cases the SEP amplitude was rapidly restored, either spontaneously or by repositioning of the recording electrode; they had no postoperative neurological changes. One patient had delayed onset of postoperative symptoms referrable to nerve root lesions without evidence of spinal cord involvement, but there were no false negative cases of intra-operative spinal cord damage. In 52 patients persistent, significant, SEP changes were noted without clinically detectable neurological sequelae. None of the many cases which showed falls in SEP amplitude of less than 50% experienced neurological problems. Neuromuscular scoliosis, the use of sublaminar wires, the magnitude of SEP decrement, and a limited or absent intra-operative recovery of SEP amplitude were identified as factors which increased the risk of postoperative neurological deficit.

We studied the effects of high-dose irradiation on the mechanical properties and morphology of cortical bone in rabbits for 52 weeks after a single dose of 50 Gy of electron-beam to the tibia. After four weeks, the bending strength of the irradiated bone was unchanged, but at 12 weeks, the strength had decreased significantly. At 24 weeks after irradiation mean strength was less than half of controls but by 52 weeks there was a tendency toward recovery. Similar, synchronous changes of damage and recovery were seen in cortical porosity, haematopoietic cells in the bone marrow and endosteal new bone formation.

Needle biopsies, performed on 208 consecutive patients and interpreted at the London Bone Tumour Service over a two-year period, were reviewed. A correct diagnosis was reached in 97% (133 out of 137) using this technique alone. Needle biopsy is safe and accurate when undertaken in consultation within a bone tumour service; it offers considerable advantages to both patient and surgeon over conventional open biopsy.

Revascularisation of syngeneic and allogeneic intramuscular bone grafts have been studied using radioactive microspheres to measure the ingrowth of blood vessels. New bone formation and resorption were measured by 85strontium uptake and by graft weight reduction. Revascularisation, and mineralisation rate were significantly higher in syngeneic grafts than in allogeneic grafts at two, three and six weeks after implantation. The syngeneic grafts lost weight faster indicating that the allogeneic grafts resorbed more slowly. The ingrowth of new vessels is impaired in allogeneic bone, and this probably inhibits the rate of bone formation and resorption of the grafts.

Intramedullary rods manufactured from polyacetal were used to fix diaphyseal fractures in osteoporotic bone. They are pliable and can be introduced without further damage to such bone. Their low elastic modulus induces abundant callus. They can be locked with cortical bone screws without the need of jigs or radiographic control. Nine femoral and five tibial fractures were fixed in 10 patients, all with osteoporosis; 13 united primarily; one required bone grafting. No implant broke; however, no ambulant patient weighed more than 75 kg. The rods offer a promising treatment for diaphyseal fractures in osteoporotic bone.

Serum immunoglobulin concentrations in 41 children with Perthes' disease and 82 age and sex matched controls were measured by radial immunodiffusion. Significant increases in IgG and IgM were seen in children with Perthes' disease.

The postoperative morbidity after osteosynthesis of malleolar fractures was investigated retrospectively by comparing 90 alcohol abusers with 90 controls. The two groups were selected from 626 male patients and were matched regarding trauma, treatment for cardiovascular, pulmonary and endocrine diseases, age, weight, smoking habits, anaesthesia and duration of surgery. The alcohol abusers developed significantly more early complications, especially infections, after surgery. Follow-up at six, nine and 12 weeks after surgery also revealed a significantly higher morbidity among the alcoholics.