1. The hip joint usually acts as the fulcrum of a lever system. 2. The centre of gravity of supported parts, which is usually medial to the hip joint, exerts a rotational effect upon the pelvis. If pelvic position is to be maintained this force must be counterbalanced by hip muscles. 3. The force transmitted by the hip joint is the sum of the supported body weight and the tension in the balancing muscles. This force often exceeds the total weight of the body. 4. In some circumstances the loss of one pound of body weight relieves the hip joint of three pounds pressure. 5. A long femoral neck is an advantage to hip function, but in arthroplasty this must not lead to mechanical failure such as breaking or loosening of the prosthesis, or fracture of the bone. 6. Medial displacement of the femoral head upon the pelvis may cause a great decrease in joint pressure, but medial displacement alone of the shaft upon the head and neck does not influence the mechanics of the joint. 7. The position of the centre of gravity of supported parts is easily altered by slight variations in spinal position. Great changes in hip joint pressure are caused by small coronal spinal movements, but the advantage to man of being able to walk with the eyes steady outweighs the mechanical disadvantage to which his hip is subjected. 8. A femoral abduction osteotomy improves the mechanics of a hip joint deformed in adduction. 9. A walking stick or a crutch is most helpful in relieving joint pressure and reducing the work done by hip muscles

We describe the results of treatment of open fractures of the humerus, radius and ulna in 61 children. Most were due to low-energy trauma and were rarely associated with head or other injuries; 72% were Gustilo type I, 15% type II and 13% type III. Fifteen children (25%) had open diaphyseal, supracondylar or T-shaped fractures of the humerus. Arterial injuries occurred in two (13%) and nerve injuries in 7 (47%). All nerve injuries recovered spontaneously. The long-term results in 13 children were excellent or good in 11 (85%) and fair in two (15%). Forty-six children (75%) had open forearm fractures. Arterial injuries occurred in one (2%), nerve injuries in five (11%) and a compartment syndrome in five (11%). Ruptured radial and ulnar arteries and median and ulnar nerves were repaired in one child. All other nerve injuries resolved spontaneously. Early compartment release in five children prevented Volkmann's ischaemic contracture. Normal union occurred in only 36 children (78%). Delayed union, nonunion, malunion and refracture frequently complicated type-II and type-III fractures of the shafts of the radius and ulna. The long-term results in 38 children were excellent or good in 33 (87%), fair in 4 (11%) and poor in one (2%). The short-term results for open fractures of the humerus were better than for open fractures of the forearm, but the long-term results were similar being excellent or good in 86% of the children

We report a prospective study of the liner-metal interfaces of modular uncemented acetabular components as sources of debris. We collected the pseudomembrane from the screw-cup junction and the empty screw holes of the metal backing of 19 acetabula after an average implantation of 22 months. Associated osteolytic lesions were separately collected in two cases. The back surfaces of the liners and the screws were examined for damage, and some liners were scanned by electron microscopy. The tissues were studied histologically and by atomic absorption spectrophotometry to measure titanium content. The pseudomembrane from the screw-cup junction contained polyethylene debris in seven specimens and metal debris in ten. The material from empty screw holes was necrotic tissue or dense fibroconnective tissue with a proliferative histiocytic infiltrate and foreign-body giant-cell reaction. It contained polyethylene debris in 14 cases and metal in five. The two acetabular osteolytic lesions also showed a foreign-body giant-cell reaction to particulate debris. The average titanium levels in pseudomembranes from the screw-cup junction and the empty screw holes were 959 micrograms/g (48 to 11,900) and 74 micrograms/g (0.72 to 331) respectively. The tissue from the two lytic lesions showed average titanium levels of 139 and 147 micrograms/g respectively. The back surfaces of the PE liners showed surface deformation, burnishing, and embedded metal debris. All 30 retrieved screws demonstrated fretting at the base of the head and on the proximal shaft. Non-articular modular junctions create new interfaces for the generation of particulate debris, which may cause granulomatous reaction

A total of 45 tibial shaft fractures, all conservatively treated and with union delayed for more than 16 but less than 32 weeks were entered in a double-blind multi-centre trial. The fractures were selected for their liability to delayed union by the presence of moderate or severe displacement, angulation or comminution or a compound lesion with moderate or severe injury to skin and soft tissues. Treatment was by plaster immobilisation in all, with active electromagnetic stimulation units in 20 patients and dummy control units in 25 patients for 12 weeks. Radiographs were assessed blindly and independently by a radiologist and an orthopaedic surgeon. Statistical analysis showed the treatment groups to be comparable except in their age distribution, but age was not found to affect the outcome and the effect of treatment was consistent for each age group. The radiologist's assessment of the active group showed radiological union in five fractures, progress to union in five but no progress to union in 10. In the control group there was union in one fracture and progress towards union in one but no progress in 23. Using Fisher's exact test, the results were very significantly in favour of the active group (p = 0.002). The orthopaedic surgeon's assessment showed union in nine fractures and absence of union in 11 fractures in the active group. There was union in three fractures and absence of union in 22 fractures in the control group. These results were also significantly in favour of the active group (p = 0.02). It was concluded that pulsed electromagnetic fields significantly influence healing in tibial fractures with delayed union

1. In fifteen patients with unilateral osteoarthritis of the hip bilateral measurements of the intraosseous pressure of the femoral neck and determination of femoral vein pressure were done simultaneously. These pressure examinations were followed by bilateral intraosseous phlebography of the proximal part of the femur. 2. In a second series of fifteen patients the intraosseous pressures of the femoral head and neck were measured simultaneously before operation for osteoarthritis. 3. The pressure in the femoral vein was equal on the two sides. The intraosseous pressure in the femoral neck was always higher in the arthritic hip than on the unaffected side. In hips with osteoarthritis the pressure in the femoral head was higher than the pressure in the neck. 4. Intraosseous phlebography indicated a state of intramedullary venous engorgement in osteoarthritis. The normal channels for venous drainage from the femoral head and neck were not visible in the phlebographs from the arthritic side. Instead, drainage took place through descending intramedullary vessels to the trochanteric region and down into the femoral shaft. The emptying of intraosseous contrast material from the arthritic hip was delayed. 5. The phlebographs indicated that the abnormally high intraosseous pressure observed in osteoarthritis is caused by a high resistance to flow across the cortex of the proximal part of the femur. 6. The aching rest pain typical of severe osteoarthritis was noted only in patients with intraosseous femoral neck pressure above 40 millimetres of mercury, an indication that this type of pain is caused by intramedullary hypertension. The decrease of arteriovenous pressure difference, caused by increase of resistance to venous outflow, is probably accompanied by disturbances of nutritive flow. This "venous ischaemia" may play an important role for the structural changes of cancellous bone in osteoarthritis

Cementless surface replacement arthroplasty of the shoulder is designed to replace the damaged joint surfaces and restore normal anatomy with minimal resection of bone. We have used the Copeland shoulder arthroplasty for 14 years. Between 1986 and 2000, 285 surface replacement arthroplasties were implanted in our unit. The prosthesis has evolved during this time, but the principle of minimal bone resection has remained the same. Between 1990 and 1994, 103 Mark-2 prostheses were inserted into 94 patients (9 bilateral). The operations were carried out for the treatment of osteoarthritis, rheumatoid arthritis, avascular necrosis, instability arthropathy, post-traumatic arthropathy and cuff arthropathy. The mean follow-up was for 6.8 years (5 to 10). The best results were achieved in primary osteoarthritis, with Constant scores of 93.7% for total shoulder replacement and 73.5% for hemiarthroplasty. The poorest results were seen in patients with cuff arthropathy and post-traumatic arthropathy with adjusted Constant scores of 61.3% and 62.7%, respectively. Most patients (93.9%) considered their shoulder to be much better or better than before the operation. Of the 88 humeral implants available for radiological review, 61 (69.3%) showed no evidence of radiolucency, nor did 21 (35.6%) of the 59 glenoid prostheses. Three were definitely loose, and eight shoulders required revision (7.7%), two (1.9%) for primary loosening. The results of this series are comparable with those for stemmed prostheses with a similar follow-up and case mix. The cementless surface replacement arthroplasty diminishes the risk of complications involving the humeral shaft and periprosthetic fractures. Revision or arthrodesis can be undertaken easily since the bone stock has been maintained with no loss of length

Objectives

The aim of this study was to review the current evidence and future application for the role of diagnostic and therapeutic ultrasound in fracture management.

We studied 56 patients with fractures of the tibial shaft in a multicentre prospective randomised trial of three methods of external fixation. Group I was treated with a fixator which was unlocked at 4 to 6 weeks to allow free axial compression (axial dynamisation) with weight-bearing. Group II was treated with a fixator that was similarly unlocked at 4 to 6 weeks but included a small silicone spring which on weight-bearing could be compressed by up to 2 mm. this spring returns to its original length on cessation of weight-bearing thus allowing cycles of motion of up to 2 mm. Group III had a spring fixator like group II, but it was unlocked from the start to allow cyclical micromovement as soon as weight-bearing began. Fracture healing was monitored by the measurement of fracture stiffness. We defined healing as achieving a stiffness of 15 Nm per degree. The mean time was 14.1 weeks in group I, 15.9 weeks in group II, and 19.3 weeks in group III. The difference between groups was statistically significant (p = 0.004). The 95% confidence intervals for the average delay in healing with early cyclical micromovement (group III) as compared with later axial dynamisation (group I) was 1.8 to 8.7 weeks. The healing time in patients whose cyclical micromovement was delayed for 4 to 6 weeks (group II) was between these two extremes, but the differences from either of the other groups could have been due to patient selection. In the patients who completed the full trial, there were pin-track infections in over 60% of those in the cyclical micromovement groups compared with 20% in the axial dynamisation group (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

We have attempted to describe the epidemiology of femoral fractures in children in the West Midlands region of the National Health Service in England. Our source of data was the Regional Hospital Episode Statistics database for the years 1991-2 to 2001-2. Cases were defined as emergency hospital admissions in patients aged under 16 years, with a diagnostic code of femoral fractures in any field, and resident in the West Midlands. Between 1991-2 and 2001-2, 3272 children aged under 16 years with femoral fractures were admitted to hospital. The crude incidence during this period decreased from 0.33 to 0.22 femoral fractures/1000/year. Those caused by traffic accidents decreased by 43%, and by falls by 29%. The peak age-gender-specific incidence (0.91/1000/year) was in two-year-old boys, and this was 50% higher than in the next highest age-gender group. In the first year of life, the incidence in boys and girls was the same. Thereafter the rate in boys exceeded that in girls, varying from 1.6 times at 11 years to 4.7 times at 14 years. Falls accounted for 49% of the fractures, varying from 77% in one-year-olds to 26% in eight-year-old children. Traffic accidents were responsible for 26% of fractures varying from 55% in ten-year-old to 2% in one-year-old children. Maltreatment was recorded in 1.3% of all cases, and in 8.5% of children under one year. Twice as many fractures were seen in May to August than in January (winter). The rates of fractures were associated with deprivation for all age-gender groups. Fractures of the shaft accounted for 58% of all fractures, varying from 70% in three-year-old to 34% in 13-year-old children. Our findings show that there has been a decrease in the incidence of femoral fractures during the 1990s and early 2000s. Two-year-old boys had twice the rate than any other single-year age-gender group. More deprived areas had much higher rates which suggests the potential for greater prevention. A relatively low rate of maltreatment was recorded compared with that in some other studies

Aims

The glenohumeral joint is the most frequently dislocated articulation, but possibly due to the lower prevalence of posterior shoulder dislocations, approximately 50% to 79% of posterior glenohumeral dislocations are missed at initial presentation. The aim of this study was to systematically evaluate the most recent evidence involving the aetiology of posterior glenohumeral dislocations, as well as the diagnosis and treatment.

Aims

The purpose of this study was to determine the functional outcome and implant survivorship of mobile-bearing total ankle arthroplasty (TAA) performed by a single surgeon.

1. A radiographic investigation of a group of 241 men who had worked in compressed air at pressures up to 35 pounds per square inch gauge on the construction of tunnels under the River Clyde showed that forty-seven men (19 per cent) had one or more lesions of aseptic necrosis of bone. 2. The radiological lesions have been classified as juxta-articular, which may lead to pain and limitation of movement, and head, neck and shaft lesions, which are usually symptomless. In 10 per cent of the men the lesions were juxta-articular and therefore potentially disabling. The treatment ofjuxta-articular lesions is described and reviewed. 3. The environmental factors associated with the occurrence of aseptic necrosis of bone, the radiological and histological appearances, and the pathogenesis of the lesions are discussed. Bone lesions were found to be related directly to the number of times a man had been decompressed, to the height of pressure at which he had worked and to attacks of bends for which treatment was given. 4. When the histological and radiographic appearances of aseptic necrosis of bone in compressed air workers are compared it is clear that a radiograph may not always reveal the full extent of the lesion, and some lesions may not show up at all. The cause of the necrosis is obscure because experimental and direct evidence of bone infarction by gas bubbles is lacking. 5. The currently accepted decompression procedures and treatment of bends used in civil engineering practice, do not prevent the occurrence of aseptic necrosis of bone in compressed air workers. 6. It is suggested that periodic radiological examination of the bones of compressed air workers should be carried out and the results correlated with other information about the men and the contracts on which they have worked in order to elucidate the causative factors in aseptic necrosis of bone. A central registry has been set up by the Medical Research Council in the University of Newcastle upon Tyne to fulfil this function

Aims

In order to determine whether and for whom serial radiological evaluation is necessary in one-part proximal humerus fractures, we set out to describe the clinical history and predictors of secondary displacement in patients sustaining these injuries.

Aims

The aim of this study was to investigate whether clinical and radiological outcomes after intramedullary nailing of displaced fractures of the fifth metacarpal neck using a single thick Kirschner wire (K-wire) are noninferior to those of technically more demanding fixation with two thinner dual wires.

Aims

We investigated patient characteristics and outcomes of Vancouver type B periprosthetic fractures treated with femoral component revision and/or osteosynthesis.