1. A predictable pattern of degeneration occurs on both the femoral head and the acetabulum and this pattern is age dependent. 2. The degenerative areas on the femoral head are related to habitual non-use. 3. The hip is shown to be anatomically incongruent, and the dome of the acetabulum, a predictable area of degeneration, is shown also to be an area of habitual non-use. 4. The possible relationships between age-dependent degenerative changes and senile degenerative joint disease is discussed and the importance of changing geometry stressed

Avascular necrosis is a serious complication of slipped capital femoral epiphysis and is difficult to treat. The reported incidence varies from 3% to 47% of patients. The aims of treatment are to maintain the range of movement of the hip and to prevent collapse of the femoral head. At present there are no clear guidelines for the management of this condition and treatment can be difficult and unrewarding. We have used examination under anaesthesia and dynamic arthrography to investigate avascular necrosis and to determine the appropriate method of treatment. We present 20 consecutive cases of avascular necrosis in patients presenting with slipped capital femoral epiphysis and describe the results of treatment with a mean follow-up of over eight years (71 to 121 months). In patients who were suitable for joint preservation (14), we report a ten-year survivorship of the hip joint of 75% and a mean Harris hip score of 82 (44 to 98)

We performed 114 consecutive primary total hip arthroplasties with a cementless expansion acetabular component in 101 patients for advanced osteonecrosis of the femoral head. The mean age of the patients at surgery was 51 years (36 to 62) and the mean length of follow-up was 110 months (84 to 129). The mean pre-operative Harris hip score of 47 points improved to 93 points at final follow-up. The polyethylene liner was exchanged in two hips during this period and one broken acetabular component was revised. The mean linear wear rate of polyethylene was 0.07 mm/year and peri-acetabular osteolysis was seen in two hips (1.9%). Kaplan-Meier analysis indicated that the survival of the acetabular component without revision was 97.8% (95% confidence interval 0.956 to 1.000) at ten years. Our study has shown that the results of THA with a cementless expansion acetabular component and an alumina-polyethylene bearing surface are good

Eleven patients with tears of the acetabular labrum are discussed and the syndrome of the torn labrum is defined. In all cases the lesion was associated with acetabular dysplasia, and a constant early radiological sign was a cyst in the lateral aspect of the acetabulum. The diagnosis was confirmed by arthrography. It is suggested that these tears are degenerative, occurring as a consequence of abnormal stresses imposed by the uncovered lateral portion of the femoral head. Once a tear is present a localised stress point occurs on the femoral head, leading rapidly to degenerative arthritis

Aims

Responsiveness and ceiling effects are key properties of an outcome score. No such data have been reported for the original English version of the International Hip Outcome Tool 12 (iHOT-12) at a follow-up of more than four months. The aim of this study was to identify the responsiveness and ceiling effects of the English version iHOT-12 in a series of patients undergoing hip arthroscopy for intra-articular hip pathology at a minimum of one year postoperatively.

Aims

This single-centre observational study aimed to describe the results of extensive bone impaction grafting of the whole acetabular cavity in combination with an uncemented component in acetabular revisions performed in a standardized manner since 1993.

We developed a method of applying vibration to the impaction bone grafting process and assessed its effect on the mechanical properties of the impacted graft. Washed morsellised bovine femoral heads were impacted into shear test rings. A range of frequencies of vibration was tested, as measured using an accelerometer housed in a vibration chamber. Each shear test was repeated at four different normal loads to generate stress-strain curves. The Mohr-Coulomb failure envelope from which shear strength and interlocking values are derived was plotted for each test. The experiments were repeated with the addition of blood in order to replicate a saturated environment. Graft impacted with the addition of vibration at all frequencies showed improved shear strength when compared with impaction without vibration, with 60 Hz giving the largest effect. Under saturated conditions the addition of vibration was detrimental to the shear strength of the aggregate. The civil-engineering principles of particulate settlement and interlocking also apply to impaction bone grafting. Although previous studies have shown that vibration may be beneficial in impaction bone grafting on the femoral side, our study suggests that the same is not true in acetabular revision

The vertical-centre-anterior margin (VCA) angle quantifies the anterior cover of the femoral head. However, when the femoral head is deformed it may be difficult to identify its centre. We have therefore created a new index, the anterior acetabular head index (AAHI) which is measured on the false-profile radiograph. We measured the VCA and AAHI angles in 312 hips in which the centre-edge angle was > 25°. There were 250 patients, 86 men and 164 women, whose ages ranged from 20 to 65 years. The mean AAHI was 84.1% (81.7% in women and 88.5% in men). There was a correlation between the AAHI and VCA angles. Our data suggest that the AAHI is useful in the evaluation of anterior acetabular cover and that it is higher in men than in women

Aims

The aim of this study is to evaluate the clinical results of operative intervention for femoral metastases which were selected based on expected survival and to discuss appropriate surgical strategies.

Aims

The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components.

We report the contamination rate in the Cambridge bone bank of 35 consecutive allograft specimens, all harvested in a clean-air environment, using a strict aseptic technique and antibiotic cover. Five of 27 femoral heads taken from living donors and three of eight massive allografts taken from cadavers were found to be contaminated. The contaminated femoral heads were discarded. All massive allografts were rendered sterile by gamma-irradiation. It is important to exclude bacteriological contamination of harvested and banked bone

This retrospective study describes the long-term results of core decompression and placement of a non-vascularised bone graft in the management of avascular necrosis of the femoral head. We treated 80 hips in 65 patients, 18 by a cortical tibial autograft and 62 by a fibular allograft. The mean age of the patients was 36 years (. sd. 13.2). A total of 78 hips were available for evaluation of which pre-operatively six were Ficat-Arlet stage 0, three stage I, 31 stage IIA, 16 stage IIB, 13 stage III and nine stage IV. A total of 34 hips (44%) were revised at a mean of four years (. sd. 3.8). Survivorship analysis using a clinical end-point showed a survival rate of 59% five years after surgery. We found a significant difference (p = 0.002) in survivorship, when using a clinical and radiological end-point, between the two grafts, in favour of the tibial autograft. We considered this difference to be the result of the better quality and increased volume of tibial bone compared with that from the trochanteric region used with the fibular allograft. This is a relatively simple, extra-articular and reproducible procedure. In our view core decompression, removal of the necrotic tissue and packing of the cancellous grafts into the core track are vital parts of the procedure

Aims

The aim of this study was to identify modifiable risk factors associated with mortality in patients requiring revision total hip arthroplasty (THA) for periprosthetic hip fracture.

The efficacy of traction before an attempted closed reduction for patients with developmental dislocation of the hip remains controversial. We treated 55 children (62 dislocations of the hip) by preliminary, prolonged traction for a mean of eight weeks. All were followed up for at least two years in order to observe the development of any avascular changes within the femoral head. Of the 55 children, 27 (31 dislocations) were followed up until they were over six years of age. Fifty-seven of the 62 hips (92%) showed a successful closed reduction. Only one had radiological evidence of avascular necrosis of the femoral head. Of the 31 hips which were followed up to over six years of age, 15 (48%) showed residual subluxation. Our method of prolonged preliminary traction leads to a high rate of successful closed reduction, a low incidence of avascular necrosis and a reduced need for secondary operations

Aims

Accurate estimations of the risk of fracture due to metastatic bone disease in the femur is essential in order to avoid both under-treatment and over-treatment of patients with an impending pathological fracture. The purpose of the current retrospective in vivo study was to use CT-based finite element analyses (CTFEA) to identify a clear quantitative differentiating factor between patients who are at imminent risk of fracturing their femur and those who are not, and to identify the exact location of maximal weakness where the fracture is most likely to occur.

Aims

The aim of the current study was to assess the reliability of the Ottawa classification for symptomatic acetabular dysplasia.

Salvage of a failed total ankle replacement is technically challenging and although a revision procedure may be desirable, a large amount of bone loss or infection may preclude this. Arthrodesis can be difficult to achieve and is usually associated with considerable shortening of the limb. We describe a technique for restoring talar height using an allograft from the femoral head compressed by an intramedullary nail. Three patients with aseptic loosening were treated successfully by this method with excellent symptomatic relief at a mean follow-up of 32 months (13 to 50)

We describe 95 patients with previously treated congenital dislocation of the hip who underwent femoral osteotomy after the age of five years. The commonest indication for surgery was progressive uncovering and subluxation of the femoral head; other reasons were coxa vara, long leg dysplasia and persistent anteversion. Femoral osteotomy for uncovering of the femoral head (Severin Grade III) in this age group gave good results at maturity only when the acetabular angle was less than 25 degrees before operation. Femoral osteotomy alone was inadequate for true subluxation of the hip (Severin Grade IV)

Fifty-six patients with ununited intracapsular fractures of the femoral neck were treated by internal fixation and muscle-pedicle bone grafting. All had some absorption of the femoral neck, and many had avascular necrosis of the femoral head. At operation the sclerosed surfaces of the fractures were freshened, the avascular femoral head was decompressed and the muscle-pedicle graft was fixed with silk thread wrapped around pins. Satisfactory union occurred in 42 patients (75%), and delayed union in seven, of whom four (7%) eventually united without further treatment and three united after osteotomy. Non-union occurred in five patients and technical failure in two