The computed neck-shaft angle and the size of the femoral component were recorded in 100 consecutive hip resurfacings using imageless computer-navigation and compared with the angle measured before operation and with actual component implanted. The reliability of the registration was further analysed using ten cadaver femora. The mean absolute difference between the measured and navigated neck-shaft angle was 16.3° (0° to 52°). Navigation underestimated the measured neck-shaft angle in 38 patients and the correct implant size in 11. Registration of the cadaver femora tended to overestimate the correct implant size and provided a low level of repeatability in computing the neck-shaft angle.

Prudent pre-operative planning is advisable for use in conjunction with imageless navigation since misleading information may be registered intraoperatively, which could lead to inappropriate sizing and positioning of the femoral component in hip resurfacing.

Most hip fractures treated with modern internal fixation techniques will heal. However, failures occasionally occur and require revision procedures. Salvage strategies employed during revision are based on whether the fixation failure occurs in the femoral neck, or in the intertrochanteric region. Patient age and remaining bone stock also influence decision making. For fractures in young patients, efforts are generally focused on preserving the native femoral head via osteotomies and repeat internal fixation. For failures in older patients, some kind of hip replacement is usually selected. Disuse osteopenia, deformity, bone loss, and stress-risers from previous internal fixation devices all pose technical challenges to successful reconstruction. Attention to detail is important in order to minimise complications. In the majority of cases, good outcomes have been reported for the various salvage strategies.

Cite this article: Bone Joint J 2013;95-B, Supple A:7–10.

We report the outcome at a minimum of five years of 110 consecutive metal-on-metal Birmingham Hip Resurfacing arthroplasties in 98 patients. The procedures were performed between October 1999 and June 2002 by one surgeon. All patients were followed up clinically and radiologically. The mean follow-up was 71 months (60 to 93). Revision of either component was defined as failure.

The mean Harris Hip score at follow-up was 96.4 (53 to 100). The mean Oxford hip score was 41.9 (16 to 57) pre-operatively and 15.4 (12 to 49) post-operatively (p < 0.001). The mean University of California Los Angeles activity score was 3.91 (1 to 10) pre-operatively and 7.5 (4 to 10) post-operatively (p < 0.001).

There were four failures giving a survival at five years of 96.3% (95% confidence interval 92.8 to 99.8). When applying a new method to estimate narrowing of the femoral neck we identified a 10% thinning of the femoral neck in 16 hips (14.5%), but the relevance of this finding to the long-term outcome remains unclear.

These good medium-term results from an independent centre confirm the original data from Birmingham.

Metal-on-metal total hip replacement has been targeted at younger patients with anticipated long-term survival, but the effect of the production of metal ions is a concern because of their possible toxicity to cells. We have reviewed the results of the use of the Ultima hybrid metal-on-metal total hip replacement, with a cemented polished tapered femoral component with a 28 mm diameter and a cobalt-chrome (CoCr) modular head, articulating with a 28 mm CoCr acetabular bearing surface secured in a titanium alloy uncemented shell.

Between 1997 and 2004, 545 patients with 652 affected hips underwent replacement using this system. Up to 31 January 2008, 90 (13.8%) hips in 82 patients had been revised. Pain was the sole reason for revision in 44 hips (48.9%) of which 35 had normal plain radiographs. Peri-prosthetic fractures occurred in 17 hips (18.9%) with early dislocation in three (3.3%) and late dislocation in 16 (17.8%). Infection was found in nine hips (10.0%).

At operation, a range of changes was noted including cavities containing cloudy fluid under pressure, necrotic soft tissues with avulsed tendons and denuded osteonecrotic upper femora. Corrosion was frequently observed on the retrieved cemented part of the femoral component. Typically, the peri-operative findings confirmed those found on pre-operative metal artefact reduction sequence MRI and histological examination showed severe necrosis.

Metal artefact reduction sequence MRI proved to be useful when investigating these patients with pain in the absence of adverse plain radiological features.

We present a series of 30 uncemented total hip replacements performed between June 1985 and January 2002 with a mean follow-up of seven years (5 to 20) in 27 patients who had previously undergone a valgus intertrochanteric osteotomy. No further osteotomy was undertaken to enable hip replacement. We used a number of uncemented modular or monoblock femoral components, acetabular components and bearings. The patients were followed up clinically and radiologically. We report 100% survival of the femoral component. One acetabular component was revised at five years post-implantation for aseptic loosening. We noted cortical hypertrophy around the tip of the monoblock stems in six patients. We believe that modular femoral components should be used when undertaking total hip replacement in patients who have previously undergone valgus femoral osteotomy.

Hydroxyapatite-coated standard anatomical and customised femoral stems are designed to transmit load to the metaphyseal part of the proximal femur in order to avoid stress shielding and to reduce resorption of bone. In a randomised in vitro study, we compared the changes in the pattern of cortical strain after the insertion of hydroxyapatite-coated standard anatomical and customised stems in 12 pairs of human cadaver femora. A hip simulator reproduced the physiological loads on the proximal femur in single-leg stance and stair-climbing. The cortical strains were measured before and after the insertion of the stems.

Significantly higher strain shielding was seen in Gruen zones 7, 6, 5, 3 and 2 after the insertion of the anatomical stem compared with the customised stem. For the anatomical stem, the hoop strains on the femur also indicated that the load was transferred to the cortical bone at the lower metaphyseal or upper diaphyseal part of the proximal femur.

The customised stem induced a strain pattern more similar to that of the intact femur than the standard, anatomical stem.

We have investigated the accuracy of placement of the femoral component using imageless navigation in 100 consecutive Birmingham Hip Resurfacings. Pre-operative templating determined the native neck-shaft angle and planned stem-shaft angle of the implant. The latter were verified post-operatively using digital anteroposterior unilateral radiographs of the hip.

The mean neck-shaft angle determined before operation was 132.7° (118° to 160°). The mean planned stem-shaft angle was a relative valgus alignment of 9.7° (sd 2.6). The stem-shaft angle after operation differed from that planned by a mean of 2.8° (sd 2.0) and in 86% of cases the final angle measured within ± 5° of that planned. We had no instances of notching of the neck or varus alignment of the implant in our series. A learning curve was observed in the time taken for navigation, but not for accurate placement of the implant.

Navigation in hip resurfacing may afford the surgeon a reliable and accurate method of placement of the femoral component.

We report our experience of revision total hip replacement (THR) using the Revitan curved modular titanium fluted revision stem in patients with a full spectrum of proximal femoral defects. A total of 112 patients (116 revisions) with a mean age of 73.4 years (39 to 90) were included in the study. The mean follow-up was 7.5 years (5.3 to 9.1). A total of 12 patients (12 hips) died but their data were included in the survival analysis, and four patients (4 hips) were lost to follow-up. The clinical outcome, proximal bone regeneration and subsidence were assessed for 101 hips.

The mean Harris Hip Score was 88.2 (45.8 to 100) after five years and there was an increase of the mean Barnett and Nordin-Score, a measure of the proximal bone regeneration, of 20.8 (-3.1 to 52.7). Five stems had to be revised (4.3%), three (2.9%) showed subsidence, five (4.3%) a dislocation and two of 85 aseptic revisions (2.3%) a periprosthetic infection.

At the latest follow-up, the survival with revision of the stem as the endpoint was 95.7% (95% confidence interval 91.9% to 99.4%) and with aseptic loosening as the endpoint, was 100%. Peri-prosthetic fractures were not observed.

We report excellent results with respect to subsidence, the risk of fracture, and loosening after femoral revision using a modular curved revision stem with distal cone-in-cone fixation. A successful outcome depends on careful pre-operative planning and the use of a transfemoral approach when the anatomy is distorted or a fracture is imminent, or residual cement or a partially-secured existing stem cannot be removed. The shortest appropriate stem should, in our opinion, be used and secured with > 3 cm fixation at the femoral isthmus, and distal interlocking screws should be used for additional stability when this goal cannot be realised.

Cite this article: Bone Joint J 2014;96-B:889–95.

Pre-operative planning for total hip replacement (THR) is challenging in hips with severe acetabular deformities, including those with a hypoplastic acetabulum or severe defects and in the presence of arthrodesis or ankylosis. We evaluated whether a Rapid Prototype (RP) model, which is a life-sized reproduction based on three-dimensional CT scans, can determine the feasibility of THR and provide information about the size and position of the acetabular component in severe acetabular deformities. THR was planned using an RP model in 21 complex hips in five men (five hips) and 16 women (16 hips) with a mean age of 47.7 years (24 to 70) at operation. An acetabular component was implanted successfully and THR completed in all hips. The acetabular component used was within 2 mm of the predicted size in 17 hips (80.9%). All of the acetabular components and femoral stems had radiological evidence of bone ingrowth and stability at the final follow-up, without any detectable wear or peri-prosthetic osteolysis. The RP model allowed a simulated procedure pre-operatively and was helpful in determining the feasibility of THR pre-operatively, and to decide on implant type, size and position in complex THRs.

Cite this article: Bone Joint J 2013;95-B:1458–63.

The femoral head receives blood supply mainly from the deep branch of the medial femoral circumflex artery (MFCA). In previous studies we have performed anatomical dissections of 16 specimens and subsequently visualised the arteries supplying the femoral head in 55 healthy individuals. In this further radiological study we compared the arterial supply of the femoral head in 35 patients (34 men and one woman, mean age 37.1 years (16 to 64)) with a fracture/dislocation of the hip with a historical control group of 55 hips. Using CT angiography, we identified the three main arteries supplying the femoral head: the deep branch and the postero-inferior nutrient artery both arising from the MFCA, and the piriformis branch of the inferior gluteal artery. It was possible to visualise changes in blood flow after fracture/dislocation.

Our results suggest that blood flow is present after reduction of the dislocated hip. The deep branch of the MFCA was patent and contrast-enhanced in 32 patients, and the diameter of this branch was significantly larger in the fracture/dislocation group than in the control group (p = 0.022). In a subgroup of ten patients with avascular necrosis (AVN) of the femoral head, we found a contrast-enhanced deep branch of the MFCA in eight hips. Two patients with no blood flow in any of the three main arteries supplying the femoral head developed AVN.

Cite this article: Bone Joint J 2013;95-B:1453–7.

The management of osteonecrosis of the femoral head ranges from symptomatic therapy to total hip replacement. Conservative treatment is effective only in small, early-stage lesions. Free vascularised fibular grafting has provided more consistently successful results than any other joint-preserving method. It supports the collapsing subchondral plate by primary callus formation, reduces intra-osseous pressure, removes and replaces the necrotic segment, and adds viable cortical bone graft plus fresh cancellous graft, which has osseoinductive and osseoconductive potential. Factors predisposing to success are the aetiology, stage and size of the lesion. Furthermore, it is a hip-salvaging procedure in early pre-collapse stages, and a time-buying one when the femoral head has collapsed.

Loss of bone stock is a major problem in revision surgery of the hip. Impaction bone grafting of the femur is frequently used when dealing with deficient bone stock. In this retrospective study a consecutive series of 68 patients (69 hips) who had revision of a hip replacement with femoral impaction grafting were reviewed. Irradiated bone allograft was used in all hips. Radiological measurement of subsidence of the stem, incorporation of the graft and remodelling was carried out and showed incorporation of the graft in 26 of 69 hips (38%). However, there was no evidence of trabecular remodelling. Moderate subsidence of 5 mm to 10 mm occurred in ten hips (14.5%), and massive subsidence of > 10 mm in five (7.2%).

The results of this study are less favourable than those of others describing studies of revision of the femoral stem using impaction bone grafting. The absence of the characteristic changes of graft remodelling noted in other series raises the question as to whether irradiated bone graft may be a significant factor influencing the post-operative outcome.

In 2012 we reviewed a consecutive series of 92 uncemented THRs performed between 1986 and 1991 at our institution using the CLS Spotorno stem, in order to assess clinical outcome and radiographic data at a minimum of 21 years. The series comprised 92 patients with a mean age at surgery of 59.6 years (39 to 77) (M:F 43;49).

At the time of this review, seven (7.6%) patients had died and two (2.2%) were lost to follow-up. The 23-year Kaplan–Meier survival rates were 91.5% (95% confidence intervals (CI) 85.4% to 97.6%; 55 hips at risk) and 80.3% (95% CI, 71.8% to 88.7%; 48 hips at risk) respectively, with revision of the femoral stem or of any component as endpoints. At the time of this review, 76 patients without stem revision were assessed clinically and radiologically (mean follow-up 24.0 years (21.5 to 26.5)). For the 76 unrevised hips the mean Harris hip score was 87.1 (65 to 97). Femoral osteolysis was detected in five hips (6.6%) only in Gruen zone 7. Undersized stems were at higher risk of revision owing to aseptic loosening (p = 0.0003). Patients implanted with the stem in a varus position were at higher risk of femoral cortical hypertrophy and thigh pain (p = 0.0006 and p = 0.0007, respectively).

In our study, survival, clinical outcome and radiographic data remained excellent in the third decade after implantation. Nonetheless, undersized stems were at higher risk of revision owing to aseptic loosening.

Cite this article: Bone Joint J 2014;96-B:455–61.

We report the case of a 22-year-old woman who underwent plate and screw fixation for a traumatic left acetabular fracture and fixation with cancellous screws for an associated femoral neck fracture. Two months later, the internal fixation became infected and was removed. This resulted in a painful high dislocation of the hip. We solved the problem with continuous soft-tissue distraction using a fully implantable motorised distraction nail in order to reduce the proximal femur prior to total hip arthroplasty. To our knowledge, this is the first time that reduction of a high dislocation of the hip has been performed using such a system.

The aim of this study was to assess whether a femoral component which retained the neck reduced the incidence of leg-length inequality following total hip arthroplasty. A retrospective review was undertaken of 130 consecutive primary total hip arthroplasties performed between April 1996 and April 2004 using such an implant. There were 102 suitable patients for the study. Standardised pre- and post-operative pelvic radiographs were measured by an independent investigator to the nearest millimetre.

The leg-length inequality was reduced from a mean pre-operative value of −0.71 cm to a mean of 0.11 cm post-operatively. Of the 102 patients 24 (23.5%) had an equal leg-length post-operatively, and 95 (93.1%) had a leg-length inequality between −1 cm and 1 cm.

The purpose of this study was to identify changing trends in the pattern of distribution of the type and demographics of fractures of the hip in the elderly between 2001 and 2010. A retrospective cross-sectional comparison was conducted between 179 fractures of the hip treated in 2001, 357 treated in 2006 and 454 treated in 2010. Patients aged < 60 years and those with pathological and peri-prosthetic fractures were excluded. Fractures were classified as stable extracapsular, unstable extracapsular or intracapsular fractures.

The mean age of the 179 patients (132 women (73.7%)) treated in 2001 was 80.8 years (60 to 96), 81.8 years (61 to 101) in the 357 patients (251 women (70.3%)) treated in 2006 and 82.0 years (61 to 102) in the 454 patients (321 women (70.1%)) treated in 2010 (p = 0.17). There was no difference in the gender distribution between the three study years (p = 0.68).

The main finding was a steep rise in the proportion of unstable peritrochanteric fractures. The proportion of unstable extracapsular fractures was 32% (n = 57) in 2001, 35% (n = 125) in 2006 and 45% (n = 204) in 2010 (p < 0.001). This increase was not significant in patients aged between 60 and 69 years (p = 0.84), marginally significant in those aged between 70 and 79 years (p = 0.04) and very significant in those aged > 80 years (p < 0.001). The proportion of intracapsular fractures did not change (p = 0.94).

At present, we face not only an increasing number of fractures of the hip, but more demanding and complex fractures in older patients than a decade ago. This study does not provide an explanation for this change.

Cite this article: Bone Joint J 2013;95-B:1250–4.

We investigated the clinical outcome of internal fixation for pathological fracture of the femur after primary excision of a soft-tissue sarcoma that had been treated with adjuvant radiotherapy.

A review of our database identified 22 radiation-induced fractures of the femur in 22 patients (seven men, 15 women). We noted the mechanism of injury, fracture pattern and any complications after internal fixation, including nonunion, hardware failure, secondary fracture or deep infection.

The mean age of the patients at primary excision of the tumour was 58.3 years (39 to 86). The mean time from primary excision to fracture was 73.2 months (2 to 195). The mean follow-up after fracture fixation was 65.9 months (12 to 205). Complications occurred in 19 patients (86%). Nonunion developed in 18 patients (82%), of whom 11 had a radiological nonunion at 12 months, five a nonunion and hardware failure and two an infected nonunion. One patient developed a second radiation-associated fracture of the femur after internal fixation and union of the initial fracture. A total of 13 patients (59%) underwent 24 revision operations.

Internal fixation of a pathological fracture of the femur after radiotherapy for a soft-tissue sarcoma has an extremely high rate of complication and requires specialist attention.

Cite this article: Bone Joint J 2013;95-B:1144–8.

Pre-operative computerised three-dimensional planning was carried out in 223 patients undergoing total hip replacement with a cementless acetabular component and a cementless modular-neck femoral stem. Components were chosen which best restored leg length and femoral offset. The post-operative restoration of the anatomy was assessed by CT and compared with the pre-operative plan.

The component implanted was the same as that planned in 86% of the hips for the acetabular implant, 94% for the stem, and 93% for the neck-shaft angle. The rotational centre of the hip was restored with a mean accuracy of 0.73 mm (sd 3.5) craniocaudally and 1.2 mm (sd 2) laterally. Limb length was restored with a mean accuracy of 0.3 mm (sd 3.3) and femoral offset with a mean accuracy of 0.8 mm (sd 3.1).

This method appears to offer high accuracy in hip reconstruction as the difficulties likely to be encountered when restoring the anatomy can be anticipated and solved pre-operatively by optimising the selection of implants. Modularity of the femoral neck helped to restore the femoral offset and limb length.

The medial approach for the treatment of children with developmental dysplasia of the hip (DDH) in whom closed reduction has failed requires minimal access with negligible blood loss. In the United Kingdom, there is a preference for these children to be treated using an anterolateral approach after the appearance of the ossific nucleus. In this study we compared these two protocols, primarily for the risk of osteonecrosis.

Data were gathered prospectively for protocols involving the medial approach (26 hips in 22 children) and the anterolateral approach (22 hips in 21 children) in children aged <  24 months at the time of surgery. Osteonecrosis of the femoral head was assessed with validated scores. The acetabular index (AI) and centre–edge angle (CEA) were also measured.

The mean age of the children at the time of surgery was 11 months (3 to 24) for the medial approach group and 18 months (12 to 24) for the anterolateral group, and the combined mean follow-up was 70 months (26 to 228). Osteonecrosis of the femoral head was evident or asphericity predicted in three of 26 hips (12%) in the medial approach group and four of 22 (18%) in the anterolateral group (p = 0.52). The mean improvement in AI was 8.8° (4° to 12°) and 7.9° (6° to 10°), respectively, at two years post-operatively (p = 0.18). There was no significant difference in CEA values of affected hips between the two groups.

Children treated using an early medial approach did not have a higher risk of developing osteonecrosis at early to mid-term follow-up than those treated using a delayed anterolateral approach. The rates of acetabular remodelling were similar for both protocols.

Cite this article: Bone Joint J 2014;96-B:406–13.

We evaluated the outcome of 41 consecutive Charnley low-friction arthroplasties (LFAs) performed by a single surgeon in 28 patients aged ≤ 35 years at operation between 23 and 36 years previously. There were 20 women and eight men with a mean age of 32 years (23 to 35) at surgery. Two patients (three hips) were lost to follow-up at 12 and 17 years post-operatively, respectively, and one patient (one hip) died at 13 years post-operatively. These patients were excluded from the final evaluation. The survival rate of the acetabular components was 92.7% (95% confidence interval (CI) 88.7 to 96.7) at ten years, 67.1% (95% CI 59.75 to 74.45) at 20 years and 53.2% (95% CI 45.3 to 61.1) at 25 years. For the femoral component the survival was 95.1% (95% CI 91.8 to 98.5) at ten years, 77.1% (95% CI 73.9 to 80.3) at 20 years and 68.2% (95% CI 60.7 to 75.8) at 25 years. The results indicate that the Charnley LFA remains a reasonable choice in the treatment of young patients and can serve for comparison with newer techniques and implants.

Cite this article: Bone Joint J 2013;95-B:1052–6.