The aim of this study was to investigate the possible benefit of large-head metal-on-metal bearing on a stem for primary hip replacement compared with a 28 mm diameter conventional metal-on-polyethylene bearing in a prospective randomised controlled trial. We investigated cemented stem behaviour between these two different bearings using Einzel-Bild-Röntgen-Analyse, clinical and patient reported measures (Harris hip score, Western Ontario and McMaster Universities osteoarthritis index, Short Form-36 and satisfaction) and whole blood metal ion levels at two years. A power study indicated that 50 hips were needed in each group to detect subsidence of > 5 mm at two years with a p-value of < 0.05.

Significant improvement (p < 0.001) was found in the mean clinical and patient reported outcomes at two years for both groups. Comparison of outcomes between the groups at two years showed no statistically significant difference for mean stem migration, clinical and patient reported outcomes; except overall patient satisfaction which was higher for metal-on-metal group (p = 0.05). Metal ion levels were raised above the Medicines and Healthcare products Regulatory Agency advised safety level (7 µg per litre) in 20% of the metal-on-metal group and in one patient in metal-on-polyethylene group (who had a metal-on-metal implant on the contralateral side). Two patients in the metal-on-metal group were revised, one for pseudotumour and one for peri-prosthetic fracture.

Use of large modular heads is associated with a risk of raised whole blood metal ion levels despite using a proven bearing from resurfacing. The head-neck junction or excess stem micromotion are possibly the weak links warranting further research.

The Canadian Orthopaedic Trauma Society was started in an endeavour to answer the difficult problem of obtaining enough patients to perform top-quality research into fractures. By maintaining a high standard, including randomised study design, inclusivity, open discussion among surgeons and excellent long-term follow-up, this group has become a leader in the orthopaedic research community. This annotation describes the short history, important components and spirit necessary to build a research community or team which will function well despite the difficult research environment facing individual surgeons.

Concerns have been reported to the United Kingdom National Patient Safety Agency, warning that cementing the femoral component during hip replacement surgery for fracture of the proximal femur may increase peri-operative mortality.

The National Hip Fracture Database collects demographic and outcome data about patients with a fracture of the proximal femur from over 100 participating hospitals in the United Kingdom. We conducted a mixed effects logistic regression analysis of this dataset to determine whether peri-operative mortality was increased in patients who had undergone either hemiarthroplasty or total hip replacement using a cemented femoral component. A total of 16 496 patients from 129 hospitals were included in the analysis, which showed a small but significant adjusted survival benefit associated with cementing (odds ratio 0.83, 95% confidence interval 0.72 to 0.96). Other statistically significant variables in predicting death at discharge, listed in order of magnitude of effect, were gender, American Society of Anesthesiologists grade, age, walking accompanied outdoors and arthroplasty. Interaction terms between cementing and these other variables were sequentially added to, but did not improve, the model.

This study has not shown an increase in peri-operative mortality as a result of cementing the femoral component in patients requiring hip replacement following fracture of the proximal femur.

Increased femoral head size may reduce dislocation rates following total hip replacement. The National Joint Registry for England and Wales has highlighted a statistically significant increase in the use of femoral heads ≥ 36 mm in diameter from 5% in 2005 to 26% in 2009, together with an increase in the use of the posterior approach. The aim of this study was to determine whether rates of dislocation have fallen over the same period. National data for England for 247 546 procedures were analysed in order to determine trends in the rate of dislocation at three, six, 12 and 18 months after operation during this time. The 18-month revision rates were also examined.

Between 2005 and 2009 there were significant decreases in cumulative dislocations at three months (1.12% to 0.86%), six months (1.25% to 0.96%) and 12 months (1.42% to 1.11%) (all p < 0.001), and at 18 months (1.56% to 1.31%) for the period 2005 to 2008 (p < 0.001). The 18-month revision rates did not significantly change during the study period (1.26% to 1.39%, odds ratio 1.10 (95% confidence interval 0.98 to 1.24), p = 0.118). There was no evidence of changes in the coding of dislocations during this time.

These data have revealed a significant reduction in dislocations associated with the use of large femoral head sizes, with no change in the 18-month revision rate.

During hip resurfacing arthroplasty, excessive valgus positioning or surgical technique can result in notching of the femoral neck. Although mechanical weakening and subsequent fracture of the femoral neck are well described, the potential damage to the retinacular vessels leading to an ischaemic event is relatively unknown. Using laser Doppler flowmetry, we measured the blood flow in 14 osteoarthritic femoral heads during routine total hip replacement surgery, before and after notching of the femoral neck. In ten hips there was a reduction in blood flow of more than 50% from the baseline value after simulated notching of the femoral neck. Our results suggest that femoral head vascularity in the osteoarthritic state is similar to the non-arthritic state, where damage to the extraosseous vessels can predispose to avascular necrosis. Surgeons who perform resurfacing arthroplasty of the hip should pay careful attention to these vessels by avoiding excessive dissection around the femoral neck and/or notching.

The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented versus uncemented fixation showed no advantage of either with regard to bone loading. When the Birmingham hip resurfacing femoral component was fixed to bone, proximal femoral stresses and strains were non-physiological. Bone resorption was predicted in the inferomedial and superolateral bone within the Birmingham hip resurfacing shell. Resorption was limited to the superolateral region when the stem was not fixed. The increased bone strain observed adjacent to the distal stem should stimulate an increase in bone density at that location. The remodelling of bone seen during revision of failed Birmingham hip resurfacing implants appears to be consistent with the predictions of our finite element analysis.

Fluoronavigation is an image-guided technology which uses intra-operative fluoroscopic images taken under a real-time tracking system and registration to guide surgical procedures. With the skeleton and the instrument registered, guidance under an optical tracking system is possible, allowing fixation of the fracture and insertion of an implant. This technology helps to minimise exposure to x-rays, providing multiplanar views for monitoring and accurate positioning of implants. It allows real-time interactive quantitative data for decision-making and expands the application of minimally invasive surgery. In orthopaedic trauma its use can be further enhanced by combining newer imaging technologies such as intra-operative three-dimensional fluoroscopy and optical image guidance, new advances in software for fracture reduction, and new tracking mechanisms using electromagnetic technology. The major obstacles for general and wider applications are the inability to track individual fracture fragments, no navigated real-time fracture reduction, and the lack of an objective assessment method for cost-effectiveness.

We believe that its application will go beyond the operating theatre and cover all aspects of patient management, from pre-operative planning to intra-operative guidance and postoperative rehabilitation.

We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers.

Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running.

We investigated the excess mortality risk associated with fractures of the hip. Data related to 29 134 patients who underwent surgery following a fracture of the hip were obtained from the Scottish Hip Fracture Audit database. Fractures due to primary or metastatic malignancy were excluded. An independent database (General Register Office (Scotland)) was used to validate dates of death. The observed deaths per 100 000 of the population were then calculated for each group (gender, age and fracture type) at various time intervals up to eight years. A second database (Interim Life Tables for Scotland, Scottish Government) was then used to create standardised mortality ratios. Analysis showed that mortality in patients aged > 85 years with a fracture of the hip tended to return to the level of the background population between two and five years after the fracture. In those patients aged < 85 years excess mortality associated with hip fracture persisted beyond eight years. Extracapsular hip fractures and male gender also conferred increased risk.

We systematically reviewed the peer-reviewed literature to relate the survival of hybrid metal-on-metal hip resurfacing arthroplasty devices to a National Institute of Clinical Excellence (NICE) benchmark for choosing a primary total hip replacement, which is a survival rate of 90% at a follow-up of ten years.

A total of 29 articles (10 621 resurfaced hips) met the inclusion criteria. The mean follow-up ranged from 0.6 to 10.5 years and the survival of the implant ranged from 84% to 100%. Of the 10 621 hips, 370 were revised (3.5%), with aseptic loosening as the most frequent mode of failure.

None of the hip resurfacing arthroplasty implants used to date met the full ten-year NICE benchmark of survival. A total of 13 studies showed satisfactory survival compared with the three-year NICE benchmark.

Despite the increasing interest and subsequent published literature on hip resurfacing arthroplasty, little is known about the prevalence of its complications and in particular the less common modes of failure. The aim of this study was to identify the prevalence of failure of hip resurfacing arthroplasty and to analyse the reasons for it.

From a multi-surgeon series (141 surgeons) of 5000 Birmingham hip resurfacings we have analysed the modes, prevalence, gender differences and times to failure of any hip requiring revision. To date 182 hips have been revised (3.6%). The most common cause for revision was a fracture of the neck of the femur (54 hips, prevalence 1.1%), followed by loosening of the acetabular component (32 hips, 0.6%), collapse of the femoral head/avascular necrosis (30 hips, 0.6%), loosening of the femoral component (19 hips, 0.4%), infection (17 hips, 0.3%), pain with aseptic lymphocytic vascular and associated lesions (ALVAL)/metallosis (15 hips, 0.3%), loosening of both components (five hips, 0.1%), dislocation (five hips, 0.1%) and malposition of the acetabular component (three hips, 0.1%). In two cases the cause of failure was unknown.

Comparing men with women, we found the prevalence of revision to be significantly higher in women (women = 5.7%; men = 2.6%, p < 0.001). When analysing the individual modes of failure women had significantly more revisions for loosening of the acetabular component, dislocation, infection and pain/ALVAL/metallosis (p < 0.001, p = 0.004, p = 0.008, p = 0.01 respectively).

The mean time to failure was 2.9 years (0.003 to 11.0) for all causes, with revision for fracture of the neck of the femur occurring earlier than other causes (mean 1.5 years, 0.02 to 11.0). There was a significantly shorter time to failure in men (mean 2.1 years, 0.4 to 8.7) compared with women (mean 3.6 years, 0.003 to 11.0) (p < 0.001).

We have evaluated the in vivo migration patterns of 164 primary consecutive Charnley-Kerboull total hip replacements which were undertaken in 155 patients. The femoral preparation included removal of diaphyseal cancellous bone to obtain primary rotational stability of the stem before line-to-line cementing. We used the Ein Bild Roentgen Analyse femoral component method to assess the subsidence of the femoral component.

At a mean of 17.3 years (15.1 to 18.3) 73 patients were still alive and had not been revised, eight had been revised, 66 had died and eight had been lost to follow-up. The mean subsidence of the entire series was 0.63 mm (0.0 to 1.94). When using a 1.5 mm threshold, only four stems were considered to have subsided. Our study showed that, in most cases, a highly polished double-tapered stem cemented line-to-line does not subside at least up to 18 years after implantation.

We investigated whether patients who underwent internal fixation for an isolated acetabular fracture were able to return to their previous sporting activities.

We studied 52 consecutive patients with an isolated acetabular fracture who were operated on between January 2001 and December 2002. Their demographic details, fracture type, rehabilitation regime, outcome and complications were documented prospectively as was their level and frequency of participation in sport both before and after surgery. Quality of life was measured using the EuroQol-5D health outcome tool (EQ-5D).

There was a significant reduction in level of activity, frequency of participation in sport (both p < 0.001) and EQ-5D scores in patients of all age groups compared to a normal English population (p = 0.001). A total of 22 (42%) were able to return to their previous level of activities: 35 (67%) were able to take part in sport at some level. Of all the parameters analysed, the Matta radiological follow-up criteria were the single best predictor for resumption of sporting activity and frequency of participation.

The original forged Müller straight stem (CoNiCr) has shown excellent ten- to 15-year results. We undertook a long-term survival analysis with special emphasis on radiological changes within a 20-year period of follow-up.

In all, 165 primary total hip replacements, undertaken between July 1984 and June 1987 were followed prospectively. Clinical follow-up included a standardised clinical examination, and radiological assessment was based on a standardised anteroposterior radiograph of the pelvis, which was studied for the presence of osteolysis, debonding and cortical atrophy.

Survival of the stem with revision for any reason was 81% (95% confidence interval (CI), 76 to 86) at 20 years and for aseptic loosening 87% (95% CI, 82 to 90). At the 20-year follow-up, 15 of the surviving 36 stems showed no radiological changes. Debonding (p = 0.005), osteolysis (p = 0.003) and linear polyethylene wear (p = 0.016) were associated with aseptic loosening, whereas cortical atrophy was not associated with failure (p = 0.008).

The 20-year results of the Müller straight stem are comparable to those of other successful cemented systems with similar follow-up. Radiological changes are frequently observed, but with a low incidence of progression, and rarely result in revision. Cortical atrophy appears to be an effect of ageing and not a sign of loosening of the femoral component.

Metal-on-metal hip resurfacing is commonly performed for osteoarthritis in young active patients. We have observed cystic or solid masses, which we have called inflammatory pseudotumours, arising around these devices. They may cause soft-tissue destruction with severe symptoms and a poor outcome after revision surgery. The aim of this study was to determine the incidence of and risk factors for pseudotumours that are serious enough to require revision surgery.

Since 1999, 1419 metal-on-metal hip resurfacings have been implanted by our group in 1224 patients; 1.8% of the patients had a revision for pseudotumour. In this series the Kaplan-Meier cumulative revision rate for pseudotumour increased progressively with time. At eight years, in all patients, it was 4% (95% confidence interval (CI) 2.2 to 5.8). Factors significantly associated with an increase in revision rate were female gender (p < 0.001), age under 40 (p = 0.003), small components (p = 0.003), and dysplasia (p = 0.019), whereas implant type was not (p = 0.156). These factors were inter-related, however, and on fitting a Cox proportional hazard model only gender (p = 0.002) and age (p = 0.024) had a significant independent influence on revision rate; size nearly reached significance (p = 0.08). Subdividing the cohort according to significant factors, we found that the revision rate for pseudotumours in men was 0.5% (95% CI 0 to 1.1) at eight years wheras in women over 40 years old it was 6% (95% CI 2.3 to 10.1) at eight years and in women under 40 years it was 13.1% at six years (95% CI 0 to 27) (p < 0.001).

We recommend that resurfacings are undertaken with caution in women, particularly those under 40 years of age but they remain a good option in young men. Further work is required to understand the aetiology of pseudotumours so that this complication can be avoided.

In a prospective study, 93 unselected consecutive uncemented hip arthroplasties were performed in 80 patients using the titanium-coated RM acetabular component and the CLS femoral component. The mean age of the patients at operation was 52 years (28 to 81). None were lost to follow-up. In the 23 patients who had died (26 hips) only one acetabular component had been revised. In the 57 living patients (67 hips), 13 such revisions had been performed. Of the 14 revisions, seven were for osteolysis, five for loosening and two for infection.

Survival analysis of this implant showed a total probability of survival of 83% (95% confidence interval 73 to 90), with all revisions as the endpoint, and a probability of 94% (95% confidence interval 87 to 98) with revision for aseptic loosening as the endpoint, indicating reliable long-term fixation of the titanium-coated RM acetabular component.