Aims

This study describes the use of the Masquelet technique to treat segmental tibial bone loss in 12 patients.

From 1986 to 1991 we fitted 20 children with endoprostheses after resection of malignant bone tumours of the leg; six have reached skeletal maturity and are the subject of this study. Reconstruction of defects in growing limbs in which the eventual shortening can be predicted requires the use of extendable prostheses. The mean age at operation was 11 years (9.2 to 13.7) and the average follow-up period was 6.3 years (4.3 to 7.6). The diagnosis was osteosarcoma in five patients and Ewing's sarcoma in one. All tumours were Enneking stage-IIB. When seen for follow-up all patients were free from disease. The extendable implants used included the Pafford-Lewis prosthesis and the Kotz Modular Femur Tibia Reconstruction system with a compatible, newly-designed growth module. Telescope-like elongation of the prostheses was performed by insertion of a screwdriver through a small skin incision. Active epiphyseal growth in the adjacent growth plate was preserved by using prosthetic stems with a smooth surface. The mean length gained was 13.15 cm (4.5 to 19.5) requiring 53 planned procedures. Seven revision operations were necessary for complications. Functional evaluation showed excellent and good results in all cases. Stress-shielding at the site of anchorage of the prosthesis was more pronounced than in adults. Implantation of extendable endoprostheses in children provides a reasonable alternative to rotationplasty, but limb salvage requires more operations

We studied the biomechanical behaviour of three sliding fixation devices for trochanteric femoral fractures. These were a titanium alloy sideplate and lag screw, a titanium alloy sideplate and dome plunger with cement augmentation, and a stainless-steel sideplate and lag screw. We used 18 mildly osteoporotic cadaver femora, randomly assigned to one of the three fixation groups. Four displacement and two strain gauges were fixed to each specimen, and each femur was first tested intact (control), then as a two-part fracture and then as a four-part intertrochanteric fracture. A range of physiological loads was applied to determine load-bearing, load-sharing and head displacement. The four-part-fracture specimens were subsequently tested to failure to determine maximum fixation strengths and modes of failure. The dome-plunger group failed at a load 50% higher than that of the stainless-steel lag-screw group (p < 0.05) and at a load 20% higher than that of the titanium-alloy lag-screw group (NS). All 12 lag-screw specimens failed by cut-out through the femoral head or neck, but none of the dome-plunger group showed movement within the femoral head when tested to failure. Strain-gauge analysis showed that the dome plunger produced considerably less strain in the inferior neck and calcar region than either of the lag screws. Inferior displacement of the femoral head was greatest for the dome-plunger group, and was due to sliding of the plunger. The dome plunger with cement augmentation was able to support higher loads and did not fail by cut-out through the femoral head.(ABSTRACT TRUNCATED AT 250 WORDS)

Aims

There is no consensus about the best method of achieving equal leg lengths at total hip arthroplasty (THA) in patients with Crowe type-IV developmental dysplasia of the hip (DDH). We reviewed our experience of a consecutive series of patients who underwent THA for this indication.

Aims

Children treated for osteosarcoma around the knee often have a substantial leg-length discrepancy at skeletal maturity. The aim of this study was to investigate the results of staged skeletal reconstruction after a leg lengthening procedure using an external fixator in these patients.

1. Double osteotomy was performed on 1 50 knees between 1961 and 1969. The first fifty-seven cases were assessed independently. 2. The operation of osteotomy of the upper end of the tibia and the lower end of the femur is described. it is emphasised that the osteotomy sites are close to the bone ends and well within the cancellous expansion. 3. The indications for the operation are pain and loss of function in a mobile arthritic knee joint. 4. Flexion of the knee is important during the operation to allow the popliteal artery to be moved away from bone. Arteriograms at necropsy show the danger of damaging the popliteal artery when the knee is extended. 5. The operation appears to be equally effective in osteoarthritis and rheumatoid arthritis. The proliferated synovium of the active rheumatoid knee regresses rapidly following operation. 6. The operation has resulted in relief of pain and increase in function in many knees which had no deformity. When a deformity did exist before operation recurrence of the deformity did not appear to influence the result. 7. The cause of relief of symptoms after osteotomy is not known, and it is suggested that answers to the following questions should be sought: Why are some arthritic knees painful and some not ? Why does physiotherapy relieve pain ? Why does osteotomy relieve pain? Why is double osteotomy followed by regression of synovial proliferation ? Why does osteotomy sometimes fail ? Would osteotomy of one bone (tibia or femur) be sufficient?

1. A study is reported of 190 femora in 174 patients in whom self-curing acrylic cement had been present in the medullary cavity of the upper end of the femur for the fixation of an endoprosthesis for an average period of four years. 2. The bone remained radiologically normal in 81 per cent of cases. 3. Improvement in the thickness of the cortex from pre-existing atrophy was noted in 2·6 per cent. 4. In 4·7 per cent the bone showed some atrophy after insertion of the cement. This exceeded 10 per cent in only two cases. All were originally osteoporotic from polyarthritis; all were satisfactory as regards the arthroplasty itself, and the atrophy could usually be explained by disuse resulting from the state of the opposite lower extremity, or the knee on the same side. 5. In 9·4 per cent there was fusiform hypertrophy of the femoral cortex, the bony texture remaining normal. This appearance was considered physiological and benign. 6. In 2·2 per cent there were changes for which the most likely explanation is chronic non-suppurative osteitis, though no collateral evidence of infection was found. 7. In 44·8 per cent there was a thin line of condensation in the cancellous bone demarcating the outer limits of the cement. This is considered to be physiological and not to indicate failure of immobilisation. 8. In 37·2 per cent there was slight resorption of the cut surface of the calcar femorale. This is considered to be physiological and to confirm the efficacy of weight transmission by cement lower down in the medullary cavity

1 . Normal and diseased bone was obtained by biopsy from five patients suffering from Paget's disease. The tissue was studied by histology, microradiography and quantitative fluorescence microscopy using tetracycline markers. Study of the morphological changes showed that two of the biopsies could be regarded as normal, while one was osteoporotic; two biopsy specimens were in the porotic phase of Paget's disease and the remaining five were in the sclerotic phase. 2. The tetracycline markers were used to measure the linear rate at which bone was deposited on individual surfaces (appositional growth rate) in µ per day and the percentage volume of new bone added to the total volume of bone per day (bone formation rate). The values obtained for appositional growth rate in all the biopsies were of the order of 1 µ per day, but slightly higher values were obtained in the diseased tissue of each individual. The bone formation rate in normal bone from the proximal femur was about 0·04 per cent per day, about 0·13 per cent per day in the porotic phase, and about 0·4 per cent per day in the sclerotic phase of Paget's disease. 3. Although these values must be accepted with some reservation, there seems to be no doubt that there is an upper limit of about 1 µ per day to the rate of deposition of bone on an individual bone surface; this suggests that in Paget's disease the osteoblast behaves as a normal cell

1. The effect of immobilisation on bone formation has been investigated in the rat. As chlortetracycline has the property of being deposited preferentially in areas of newly deposited bone, its uptake can be used as a reflection of osseous formation. 2. One hind limb of albino rats was immobilised either by section of the second, third and fourth lumbar nerve trunks or by section of tendo calcaneus and ligamentum patellae. The incorporation of chlortetracycline was determined quantitatively in the femur and tibia of both hind limbs at intervals after immobilisation. 3. Tetracycline uptake is expressed in terms of bone weight, this being most important in order to obtain correct values. 4. A comparison between the tetracycline uptake and the weight of the bones gives information about the rate of bone destruction. 5. In animals immobilised by nerve section three phases can be distinguished: a first phase with diminished bone formation, a second with increased formation and increased destruction and a third phase with diminished bone formation. Both mechanisms, decreased formation and increased destruction, are therefore important in the production of immobilisation osteoporosis; their relative importance depending upon the duration of the immobilisation. 6. In animals immobilised by tendon section the mechanical function becomes restored in the second week as a result of healing: this explains the rapid compensation for the initial loss of weight of the bones accompanied by a marked increase in tetracycline uptake. 7. These results are discussed and compared with information in the literature. Variations in bone formation and destruction rates with time could explain the varied results reported by other authors

1. Three groups of one month old rats were fed for a period of four to five weeks on a rachitogenic diet (group R), the same rachitogenic diet with vitamin D (group N), and a complete diet (group S). 2. Young's modulus of elasticity E for bone can be derived from measurements of the deflexion of the centre of a femur loaded at the centre and supported at its ends. 3. The three different diets produced significant differences in breaking stress S. B. , Young's modulus E, and percentage ash in the bones. It has not been shown conclusively that higher ash content alone is responsible for the greater S. B. and E values of bones produced on the better diets. 4. The value of E in group R was 0·6 x 10. 6. lb./in. 2. ; in group N 1·0 x 10. 6. lb./in. 2. ; and in group S (which can be taken as normal) 1·6 x 10. 6. lb./in. 2. . 5. There is a high correlation between S. B. and E even when the effect of diet is eliminated. 6. Although the bones produced on the good diet (group S) were much stronger than those of groups N or R, the strain at the elastic limit was the same (about 1·5 per cent.). The strain at rupture tended to be higher in groups N and R than in group S. 7. The properties of bone as a structural material are discussed

Objectives

We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days.

Objectives

The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery.

We developed a rat model of limb lengthening to study the basic mechanism of distraction osteogenesis, using a small monolateral external fixator. In 11-week-old male rats we performed a subperiosteal osteotomy in the midshaft of the femur with distraction at 0.25 mm every 12 hours from seven days after operation. Radiological and histological examinations showed a growth zone of constant thickness in the middle of the lengthened segment, with formation of new bone at its proximal and distal ends. Osteogenic cells were arranged longitudinally along the tension vector showing the origin and the fate of individual cells in a single section. Typical endochondral bone formation was prominent in the early stage of distraction, but intramembraneous bone formation became the predominant mechanism of ossification at later stages. We also showed a third mechanism of ossification, ‘transchondroid bone formation’. Chondroid bone, a tissue intermediate between bone and cartilage, was formed directly by chondrocyte-like cells, with transition from fibrous tissue to bone occurring gradually and consecutively without capillary invasion. In situ hybridisation using digoxigenin-11-UTP-labelled complementary RNAs showed that the chondroid bone cells temporarily expressed type-II collagen mRNA. They did not show the classical morphological characteristics of chondrocytes, but were assumed to be young chondrocytes undergoing further differentiation into bone-forming cells. We found at least three different modes of ossification during bone lengthening by distraction osteogenesis. We believe that this is the first report of such a rat model, and have shown the validity of in situ hybridisation techniques for the study of the cellular and molecular mechanisms involved in distraction osteogenesis

Aims

We present a retrospective review of patients treated with extracorporeally irradiated allografts for primary and secondary bone tumours with the mid- and long-term survivorship and the functional and radiographic outcomes.

Aims

The number of patients undergoing arthroscopic surgery of the hip has increased significantly during the past decade. It has now become an established technique for the treatment of many intra- and extra-articular conditions affecting the hip. However, it has a steep learning curve and is not without the risk of complications. The purpose of this systematic review was to determine the prevalence of complications during and following this procedure.

Aims

Extendible endoprostheses have been available for more than 30 years and have become more sophisticated with time. The latest generation is ‘non-invasive’ and can be lengthened with an external magnetic force. Early results have shown a worryingly high rate of complications such as infection. This study investigates the incidence of complications and the need for further surgery in a cohort of patients with a non-invasive growing endoprosthesis.

Aims

Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques.

The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate.

Out of 21 900 cases filed at the Latin-American Registry of Bone Pathology between April 1940 and July 1981, there were 987 with Paget's disease (4.51 per cent); 62 of these (6.28 per cent) were complicated by sarcoma and two were associated with giant-cell tumours of bone (osteoclastoma) without signs of malignancy. There was a slight predominance of men and the ages ranged from 45 to 87 years, with an average of 66 years. The most frequent sites were the femur (23 cases), the humerus (nine), the pelvis (10), and the tibia (nine). The low incidence of vertebral involvement (five cases) is noteworthy and is in sharp contrast to uncomplicated Paget's disease. The most common tumour type was osteosarcoma (39 cases), followed by fibrosarcoma (15 cases); other varieties (chondrosarcoma, malignant fibrous histiocytoma and reticulum-cell sarcoma) were much rarer. Most of the sarcomata occurred when the Paget's disease was polyostotic. Tumours often developed simultaneously, or at short time intervals, in the same or different bones; these bones had, in all cases, been affected by Paget's disease. The histological features of the osteosarcomata were characteristic, with large numbers of osteoclast giant cells, alternating with atypical osteoblasts, thus exaggerating the anarchic remodelling process of Paget's disease. The neighbouring areas of the pagetic bone showed an increased number of osteoclasts. These facts suggest a possible pathogenetic relationship between sarcoma and Paget's disease; the possibility of both processes having a viral aetiology is discussed