The incidence of cancer after hip replacement was studied in the 1.6 million inhabitants of Stockholm County, Sweden. A cohort of 10,785 individuals who had had hip replacement between 1974 and 1988 was followed from the date of operation to the first malignant tumour, to death, or to the end of 1989. The follow-up was based on 58,437 person-years at risk as calculated from information obtained by record-linkage with the National Cancer Registry and the National Cause-of-Death Register. The Standardised Morbidity Ratio (SMR) for all cancer sites, disregarding the length of follow-up, was 0.96 (95% CI 0.90 to 1.03). For lymphoma and leukaemia the corresponding SMR was 0.89 (0.68 to 1.14). Our results do not support previous suggestions of an increased incidence of leukaemia and lymphoma after total hip replacement.

We reviewed retrospectively 50 consecutive total hip arthroplasties with proximal femoral replacement prostheses in 49 patients. All the patients had massive bone loss. There were 31 women and 18 men who had undergone a mean of 3.1 hip operations. At the last review, 15 patients had died and two had been lost to follow-up, so that 32 patients (33 hips) were available for assessment. The mean age of the patients at the time of the operation was 60.6 years. The mean length of clinical follow-up was 11.1 +/- 4 years, and mean radiographic follow-up was 7.6 +/- 3.2 years. The average preoperative Harris hip score was 46 +/- 13 points, which improved to 80 +/- 10 points after one year and to 76 +/- 16 points at the latest follow-up. The most frequent complication was dislocation, which occurred in 11 hips. Four femoral components and seven acetabular prostheses were revised because of aseptic loosening. With revision at the end point, survivorship after total hip arthroplasty with a proximal femoral replacement prosthesis was predicted to be 64% at 12 years. Although our preliminary results of hip salvage with a proximal femoral replacement prosthesis were encouraging, a longer follow-up has shown a higher rate of failure.

We reviewed the records and radiographs of 387 cemented revisions of aseptic loose sockets after total hip replacement at a mean follow-up of 5.5 years. The clinical results were satisfactory, but at the last radiological assessment 38 sockets (9.8%) had a continuous zone of demarcation greater than 1 mm thick and another 35 (9%) showed migration. Poor acetabular bone stock had a profound influence on the outcome of revision surgery, but the results of cemented revision were comparable to those reported for cementless revision at similar mean follow-up.

We reviewed prospectively cemented stem revision in 106 patients with severe femoral endosteal bone lysis without infection. Bone grafts were not used in any of the patients. The minimum follow-up was three years (mean 6 years 4 months). At the last review 76.4% of the patients were free of pain and 17.9% had only mild or occasional discomfort; radiographs showed well-fixed stable stems in 101 (95.3%). An intramedullary cement plug was used at revision to improve stability in 97.7%. There was new endosteal osteolysis after revision in 17 patients; only two had severe changes. Seven hips (6.6%) required a second revision; only four of these (3.8%) were for stem loosening. Survivorship of the revised stem, using radiological evidence of stem loosening as the end point, was 95.8% at seven years. The results of stem revision arthroplasty using cement in the presence of massive endosteal cavitation are satisfactory.

We reviewed 12 patients six years after they had undergone total hip replacement with a cementless prosthesis, the Ribbed Hip System (Waldemar Link GmbH & Co, Hamburg, Germany). Aseptic loosening of one or both components had necessitated revision surgery in seven patients, in five within two years of operation. In view of our experience we question the wisdom of allowing the uncontrolled use of new prosthesis without postoperative surveillance.

We report the clinical outcome and survival of 100 total hip arthroplasties with Link RS cementless hip prostheses after a mean of 63 months (51 to 93). The average preoperative Merle d'Aubigne hip score was 9.4 points and the average score at the latest follow-up was 15.3 points. Thirteen prostheses have been revised and seven await revision. Survivorship analysis based on intention to revise showed only 68% survival at seven years (95% CI 53% to 81%). The survivals of femoral and acetabular components verified to be loose at surgery were 78% and 89% respectively at seven years. A number of other patients have pain and it seems likely that there will be substantial reduction in these survival figures in the future.

We have compared the findings of MRI with those of hip arthroscopy in 23 hips in young adults with hip pain. Large deep cartilage deficiencies on the acetabulum or femoral head, the percentage of femoral head cover, and the presence of marginal osteophytes seen on MRI correlated well with those seen at arthroscopy, but chondral softening, fibrillation, or partial-thickness defects less than 1 cm in diameter were less consistently detected by MRI. Osteochondral loose bodies and labral tears were not well demonstrated by MRI, but were readily identified and treated at arthroscopy. Arthroscopy of the hip is a useful investigation for hip pain in young adults especially when standard non-invasive MRI fails to provide a clear diagnosis.

The tibial components in 143 patients with total knee replacements performed before 1988 were assessed for micromotion using roentgen stereophotogrammetric analysis (RSA) over a period of 13 years. The fixation of the prostheses remained clinically sound in all cases, although revision had been required for other reasons in seven. In a second group taken from all cases with RSA available on our full database to 1990, 15 tibial components had been followed by RSA from the insertion until, 1 to 11 years after the initial arthroplasty, they were revised for mechanical loosening of the tibial component; 12 of these comprised all the loosenings in the base group, thus making a total of 155 consecutive cases, while an additional three were inserted after the base material had been compiled. The mean migration in the first group was about 1 mm at one year, but subsequent migration was slower, reaching a mean of about 1.5 mm after ten years. About one-third migrated continuously throughout follow-up, while two-thirds ceased to migrate after one to two years. In the revision group, 14 components had migrated continuously and at one year significantly more than those in the first group. One revision case lacked the crucial one-year follow-up and could not be classified. These findings suggest that mechanical loosening begins early in the postoperative period. Clinical symptoms which necessitate revision, seen at this stage in 20% of abnormally migrating tibial components, may not appear until up to ten years after the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

We report a case in which the popliteal artery was divided during upper tibial osteotomy performed with the knee in 90 degrees of flexion. This position is believed to allow it to fall safely back from the tibia, but we could find no published confirmation. We used duplex ultrasonography in ten healthy volunteers to measure the distance from the popliteal artery to the posterior surface of the tibia at various degrees of flexion of the knee. Our results showed that in 12 of 20 knees the popliteal artery was closer to the tibia in 90 degrees of knee flexion than in full extension. Surgeons performing upper tibial osteotomy should be aware that flexing the knee does not protect the popliteal artery from injury.

We report the treatment in 17 patients of 27 angular deformities of the long bones by progressive opening-wedge osteotomy. The technique consists of percutaneous osteotomy and progressive angular correction using a modified Wagner distractor. Ten patients (20 bone segments) had adolescent bilateral idiopathic tibia vara with a mean angular deformity of 12 degrees varus (10 to 16). Seven other adolescent patients had secondary angular deformities either at the distal femur or the distal tibia. One of the femoral deformities had an associated 5.5 cm of shortening which was treated simultaneously. The patients with idiopathic tibia vara achieved a final mean angular correction of 15 degrees (mechanical axis from 12 degrees varus to 3 degrees valgus). In patients with secondary angular deformities the mean angular correction was 17 degrees. The Wagner device was removed in an average period of 12 weeks (9 to 27), and no major complications were observed. Progressive opening-wedge osteotomy is an alternative to conventional osteotomies for the treatment of angular deformities of the long bones in adolescent patients, and has the advantage of requiring less invasive surgery, allowing progressive and adjustable correction with bone lengthening if needed.

The case histories and investigations for five adolescent girls with a presumed diagnosis of either primary acetabular protrusio or acute idiopathic chondrolysis are presented. The follow-up ranged from three to nine years. All were treated by extensive soft-tissue release but in no case did this improve movement of the affected hip and permanent stiffness was the inevitable result. The literature is reviewed and methods of treatment are discussed in the light of the CT findings.

We studied the long-term results of the Miller operation at a mean age of 13 years in 22 patients (38 feet) with persistently symptomatic mobile flat feet associated with an isolated naviculocuneiform break. At a mean of 12 years (3 to 27) after surgery, 84% of the feet had a satisfactory clinical result. We conclude that the Miller operation is a useful procedure for adolescent patients with persistently symptomatic flat feet with an isolated break at the naviculocuneiform joint.

We have developed a method of measuring anterior displacement of the calcaneus on the talus in instability of the subtalar joint and have used the technique to demonstrate anterior instability in 50 patients (72 feet) showing a positive drawer sign. The angle of the posterior facet of the talus was also measured to assess the bony configuration. Our patients with subtalar joint instability could be divided into three categories. The first group had a history of trauma leading to ankle instability (26 cases), the second showed generalised joint laxity (10 cases) and the third were young females with a history of chronic stress on the foot and a poor bony block (14 cases). Satisfactory results were obtained by treating the instability with a brace or by reconstruction of the interosseous talocalcaneal ligament.

Exchange nailing for failure of union after primary intramedullary nailing of the tibia is widely used but the indications and effectiveness have not been reported in detail. We have reviewed 33 cases of uninfected nonunion of the tibia treated by exchange nailing. This technique was successful without open bone grafting in all closed fractures and in open fractures of Gustilo types I, II and IIIa. The requirement for open bone grafting was reduced in type-IIIb fractures, but exchange nailing failed in type-IIIb fractures with significant bone loss. For these we recommend early open bone grafting. The most common complication was wound infection, seen more often than after primary nailing. We discuss our protocol for the use and timing of exchange nailing of all grades and types of tibial fracture.

We studied the effect of 'dynamisation' on tibial fractures in six patients treated by the Dynamic Axial Fixator. In the early stages, peak cyclic movement at two to four weeks averaged 0.75 mm (0.19 to 1.02) on the medial side of the bone and 0.86 mm (0.21 to 1.25) on the lateral side. The amount of movement correlated with the applied load and the fracture stiffness. After unlocking the fixator column at six weeks, progressive closure of the gap averaged 1.3 mm (0.1 to 3.5). Cyclic movement is produced by early weight-bearing with the fixator column locked. Progressive closure occurs after unlocking the column, and is often associated with a reduction in cyclic movements. The effects of dynamisation on movement at the fracture site should be defined separately, in terms of cyclic movement and of progressive closure.

We performed an epidemiological analysis of 523 fractures treated in the Edinburgh Orthopaedic Trauma Unit over a three-year period using modern descriptive criteria. The fractures were defined in terms of their AO morphology and their degree of comminution, location and cause. Closed fractures were classified using the Tscherne grading system and open fractures according to the Gustilo classification. Further analysis of fractures caused by road-traffic accidents and football was carried out. The use of the AO classification allowed the common fracture patterns to be defined. Correlation of the classification systems showed an association between the AO morphological system and the Tscherne and Gustilo classifications. The relative rarity of severe tibial fractures is indicated and it is suggested that in smaller orthopaedic units the infrequency of these fractures has implications for training and the development of treatment protocols.

Since 1986 we have treated 15 patients with fractures of the head of the radius limited to one or two fragments (Mason type II) by open reduction and internal fixation with the Fibrin Adhesive System. At a mean follow-up of over two years, all but one of the results were excellent. This method is recommended for the treatment of selected fractures of the radial head followed by early mobilisation.

We have reviewed 12 fractures of the coracoid process. In two of these patients the fracture extended into the body of the scapula and resulted in displacement of the glenoid. In some cases, there were associated acromioclavicular and glenohumeral dislocations or fractures of the clavicle and the acromion. Two patients required internal fixation to restore congruence of the glenoid; the others were treated conservatively with success. We present a new classification of coracoid fractures which helps in their management.

We report the results in the first 16 patients treated in Sheffield using bifocal techniques for diaphyseal bone loss and deformity secondary to trauma. Eight patients had bone-transport and eight had compression-distraction methods. At a mean follow-up of 24 months all 16 had excellent or good results with union of the fracture, correction of deformity and normal or near normal leg length. There were no major complications. Mean treatment times were 16 months for bone transport and 9.8 months for compression-distraction. Bone transport was more complicated requiring an average of 2.2 additional operations compared with only one for compression-distraction. Femoral cases had shorter treatment indices than tibial cases but had less favourable outcomes.

We performed a retrospective study of the factors affecting the outcome of Weber type-C ankle fractures in 43 patients reviewed at two to nine years after injury. We determined the functional result in relation to the use of a diastasis screw, the accuracy of reduction, the presence of tibiotalar dislocation, and of injury to the medial side of the ankle by medial malleolar fracture or deltoid ligament rupture. We assessed the use of a diastasis screw as appropriate or inappropriate on the basis of an anatomical study performed by Boden et al (1989). The diastasis screw was used unnecessarily in 19 of the 31 patients so treated, but this did not appear to affect the final functional result. The worse functional results were in ankles dislocated at the initial injury, and in those with medial malleolar fractures as opposed to those with deltoid ligament ruptures. The best results were after accurate reduction of the fibula and the syndesmosis, and greater increase in the width of the syndesmosis was associated with a worse result. Our results suggest that an increase of more than 1.5 mm in syndesmosis width is unacceptable. We recommend that when the deltoid ligament is ruptured, a diastasis screw should be used if the fibular fracture is more than 3.5 cm above the top of the syndesmosis. When a medial malleolar fracture has been rigidly repaired a diastasis screw is required if the fibular fracture is more than 15 cm above the syndesmosis.

Combined bony and vascular injuries present challenging problems to orthopaedic and vascular surgeons. The use of temporary intraluminal vascular shunts produces significant reductions in ischaemia time and allows fracture stabilisation to be performed before definitive, delicate vascular repair. We report our management of a five-week-old infant who sustained a comminuted fracture of the femur with arterial and venous injuries in a shooting incident. Paediatric nasogastric feeding tubes were used as temporary vascular shunts to re-establish the distal circulation. Stabilisation of the fracture was then followed by vascular reconstruction and soft-tissue surgery, with a good result. We emphasise the need for skills from several surgical disciplines in the management of complex combined injuries.

We have developed a teaching programme for non-radiologists who use fluoroscopy, which includes techniques for reducing the radiation received by the patient and the surgeon during orthopaedic procedures. The techniques resolve around the radiation protection concepts of time, distance and shielding. The programme has been very successful in reducing the total fluoroscopy times of orthopaedic surgeons; in our institute, durations have been reduced to about 10% of those before the training started. We review the aims and content of our programme.

Melioidosis is an uncommon infection caused by a Gram-negative bacillus, Pseudomonas pseudomallei. Only a few case reports of orthopaedic infection have been published in English, and most were of isolated septic arthritis or secondary to melioidosis of another organ. We have reviewed ten patients with localised melioidotic osteomyelitis; six had underlying conditions. We discuss the importance of obtaining a bacteriological diagnosis, and of surgical debridement as well as appropriate antibiotic therapy.

We performed transoesophageal echocardiography in 111 operations (110 patients) which included medullary reaming for fresh fractures of the femur and tibia, pathological lesions of the femur, and hemiarthroplasty of the hip. Embolic events of varying intensity were seen in 97 procedures and measured pulmonary responses correlated with the severity of embolic phenomena. Twenty-four out of the 25 severe embolic responses occurred while reaming pathological lesions or during cemented hemiarthroplasty of the hip and, overall, pathological lesions produced the most severe responses. Paradoxical embolisation occurred in four patients, all with pathological lesions of the femur (21%); two died. In 12 patients large coagulative masses became trapped in the heart. Extensive pulmonary thromboembolism with reamed bone and immature clot was found at post-mortem in two patients; there was severe systemic embolisation of fat and marrow in one who had a patent foramen ovale and widespread mild systemic fat embolisation in the other without associated foraminal defect. Sequential analysis of blood from the right atrium in five patients showed considerable activation of clotting cascades during reaming.

We randomised 24 patients before they had a cemented hemiarthroplasty for hip fracture to receive either thorough or minimal saline lavage of the femoral canal. We then determined the effect in each group on the thromboembolic and cardiopulmonary responses to the pressurised insertion of cement, using transoesophageal echocardiography to show the echogenic embolic response. We found a statistically significant reduction in both the duration of the response and the number of large emboli in patients who had had thorough lavage as compared with the control group with minimal lavage. There was also less disturbance of pulmonary function, as assessed by the change in end-tidal CO2 levels and oxygen saturation, in patients who had thorough lavage. Three patients had a significant fall in blood pressure during cement insertion; all had only minimal lavage. We consider that thorough lavage should be an essential part of the preparation of the proximal femur before cement insertion.

We studied the most superficial layer of macroscopically normal articular cartilage obtained from human femoral heads, using polarising microscopy and SEM. The most superficial layer, 4 to 8 microns thick, was acellular consisting of collagen fibrils. This layer could be peeled away as a thin film, with no broken collagen fibrils on its inferior surface or on the surface of subjacent cartilage layers. The orientation and diameter of collagen fibrils were different on these two surfaces. Our findings suggest that the most superficial layer is an independent one which is only loosely connected to the fibrous structure in the layer deep to it.

We report the finding of sodium- and phosphorus-based crystallisation in abnormal human articular cartilage. We prepared five chondromalacic, five osteoarthritic and four macroscopically normal specimens of patellar cartilage by a cryofracturing technique and examined them in a scanning electron microscope. An energy-dispersive X-ray microanalysis system was used to identify the crystals, which were found in only three of the five chondromalacic specimens. Star-shaped crystals were seen either individually or in clusters in the matrix of the cartilage. They consisted of sodium and phosphorus, and we have found no previous reports of such findings. The calcified zone, the bone, and the articular surface were free from crystals.

The midsagittal and interpedicular diameters and the trefoil shape of lumbar vertebrae of known age at death were measured in skeletons from a population aged between 1 and 70 years. All the trefoil configurations were at L5 with the exception of one at L4. The overall prevalence was 25%, but this shape was not generally apparent until adulthood. The midsagittal diameter in the trefoil canals was found to be significantly smaller than that in the unaffected canals. This did not change significantly after six years of age indicating that the cause of the trefoil configuration is probably present early in life. The trefoil shape was no more common in the spines of the elderly subjects. Our findings indicate that the trefoil configuration of the lumbar vertebral canal has a developmental origin and is not a consequence of degenerative processes.

We evaluated changes in bone mineral density (BMD) after tibial fractures, both at the site of fracture and at adjacent sites, using dual-energy X-ray absorptiometry. Five patients were studied prospectively for six months after fractures of the midshaft treated by intramedullary nailing or the application of an external fixator. We also reviewed 21 adult and 10 children who had sustained fractures of the tibia at least five years previously, comparing BMD in the injured limb with that in the non-injured limb and in a control group of 10 normal subjects. We found a significant fall in BMD distal to a tibial fracture; this was evident at one month, fell to approximately 50% of normal at three months and persisted at six months. We found no significant improvement with weight-bearing. Review at 5 to 11 years after adult midshaft fractures showed persistent bone loss in the distal tibia (46.5 +/- 9.8% of control values), but persisting sclerosis at old fracture sites (172 +/- 38% of control values). In contrast, we found no significant differences in BMD between the injured and control limb after fractures sustained in childhood either at the fracture site or in the distal segment. We conclude that, in adults, tibial fractures are associated with definite and persistent post-traumatic loss of distal BMD.

Dual-energy X-ray absorptiometry (DEXA) is increasingly used to measure changes in bone mineral density (BMD) around femoral prostheses after total hip arthroplasty. We have studied the factors which affect the accuracy of these measurements. The coefficient of variation was < 2% using a hydroxyapatite phantom, 2.7% in an anthropomorphic phantom specimen, and < 1% in repeated measurements on implanted cadaver femora. The precision did not vary with different implant materials or designs. In patients we found a mean precision error of 2.7% to 3.4%. The most significant factor affecting reproducibility was rotation of the femur. We conclude that DEXA is a precise method of measurement for small changes in BMD around femoral implants, but that correct and careful positioning of patients is essential to obtain reliable results.

Adult human cadaver pelves were tested to determine micromotion at the prosthesis-bone interface in cementless hemispherical acetabular components during simulated single-limb stance. The micromotion of non-press-fit components with screw fixation in response to cyclic loads to a maximum of 1500N was compressive (interface closing) at the superior iliac rim and distractive (interface opening) at the inferior ischial rim; that of press-fit components was compressive all around the acetabular rim regardless of screw fixation. Adding screws to the component decreased the micromotion at the site of the screw, but sometimes increased it at the opposite side. Two dome screws with the press-fit component decreased the micromotion at the superior iliac rim but at the inferior ischial rim there was either no change or increased movement. A press-fit cup shows less micromotion than a non-press-fit cup with screw fixation. The addition of screws to a press-fit cup does not necessarily increase the initial stability.

The tibial nutrient artery supplies 62% of cortical blood flow in the diaphysis and normal blood flow is centrifugal (Willans 1987). Intramedullary reaming destroys the nutrient artery and injures the endosteal surface of the cortex. Trueta (1974) suggested that the direction of blood flow can reverse from centrifugal to centripetal after loss of the endosteal supply. We examined this hypothesis by measuring cortical and periosteal blood flow after intramedullary reaming of the tibia in eight sheep, using 57Co radiolabelled microspheres. The unreamed contralateral tibiae served as a control group. Thirty minutes after reaming there was no significant change in cortical blood flow, but a sixfold increase in the periosteal flow. Our study confirms Trueta's hypothesis; after trauma or in other pathological states, flow can become centripetal.

We report a randomised prospective trial of the early results of three types of treatment for displaced intracapsular hip fractures. We used a questionnaire sent to patients at about six months (Nottingham Health Profile, NHP) in addition to clinical assessments. There was a 67.4% usable response to the questionnaire, similar to that in other studies using the NHP. There were more responders from younger patients, those walking independently before injury and those with higher mental test scores on admission. In the younger group (65 to 79 years) we found a trend for better scores in most NHP indices after the use of a bipolar prosthesis rather than a unipolar prosthesis or internal fixation, particularly for social function, pain and physical mobility. Postal assessment using the NHP gave a satisfactory response rate even in the elderly, and can provide an extra assessment to complement or replace hospital follow-up in some circumstances.

Solitary benign peripheral-nerve tumours are rare and may be difficult to diagnose correctly. Surgical excision may increase the patient's symptoms and may not be necessary. We have reviewed the presentation, clinical findings and histology of 104 solitary tumours presenting at one centre between 1959 and 1990. Male patients predominated for both schwannoma and neurofibroma. There was considerable but variable delay before presentation; 94% of patients complained primarily of a mass and less than half had pain or paraesthesia. The correct diagnosis had been made in only a few cases before operation, and the incidence of neurological symptoms doubled after exploration. We emphasise the need for vigilance, accurate preoperative diagnosis, and careful surgery.

Elective repair of lesions of the common peroneal nerve was carried out in 27 patients between 1982 and 1992. Twenty-three have been reviewed of whom 11 recovered power sufficient to prevent foot drop and 13 recovered protective sensation or better.