Several factors have been implicated in unsatisfactory results after total hip replacement (THR). We examined whether femoral offset, as measured on digitised post-operative radiographs, was associated with pain after THR. The routine post-operative radiographs of 362 patients (230 women and 132 men, mean age 70.0 years (35.2 to 90.5)) who received primary unilateral THRs of varying designs were measured after calibration. The femoral offset was calculated using the known dimensions of the implants to control for femoral rotation. Femoral offset was categorised into three groups: normal offset (within 5 mm of the height-adjusted femoral offset), low offset and high offset. We determined the associations to the absolute final score and the improvement in the mean Western Ontario and McMaster Universities osteoarthritis index (WOMAC) pain subscale scores at three, six, 12 and 24 months, adjusting for confounding variables.

The amount of femoral offset was associated with the mean WOMAC pain subscale score at all points of follow-up, with the low-offset group reporting less WOMAC pain than the normal or high-offset groups (six months: 7.01 (sd 11.69) vs 12.26 (sd 15.10) vs 13.10 (sd 16.20), p = 0.006; 12 months: 6.55 (sd 11.09) vs 9.73 (sd 13.76) vs 13.46 (sd 18.39), p = 0.010; 24 months: 5.84 (sd 10.23) vs 9.60 (sd 14.43) vs 13.12 (sd 17.43), p = 0.004). When adjusting for confounding variables, including age and gender, the greatest improvement was seen in the low-offset group, with the normal-offset group demonstrating more improvement than the high-offset group.

Cite this article: Bone Joint J 2014;96-B:36–42.

The increasing prevalence of osteoporosis in an ageing population has contributed to older patients becoming the fastest-growing group presenting with acetabular fractures. We performed a systematic review of the literature involving a number of databases to identify studies that included the treatment outcome of acetabular fractures in patients aged > 55 years. An initial search identified 61 studies; after exclusion by two independent reviewers, 15 studies were considered to meet the inclusion criteria. All were case series. The mean Coleman score for methodological quality assessment was 37 (25 to 49). There were 415 fractures in 414 patients. Pooled analysis revealed a mean age of 71.8 years (55 to 96) and a mean follow-up of 47.3 months (1 to 210). In seven studies the results of open reduction and internal fixation (ORIF) were presented: this was combined with simultaneous hip replacement (THR) in four, and one study had a mixture of these strategies. The results of percutaneous fixation were presented in two studies, and a single study revealed the results of non-operative treatment.

With fixation of the fracture, the overall mean rate of conversion to THR was 23.1% (0% to 45.5%). The mean rate of non-fatal complications was 39.8% (0% to 64%), and the mean mortality rate was 19.1% (5% to 50%) at a mean of 64 months (95% confidence interval 59.4 to 68.6; range 12 to 143). Further data dealing with the classification of the fracture, the surgical approach used, operative time, blood loss, functional and radiological outcomes were also analysed.

This study highlights that, of the many forms of treatment available for this group of patients, there is a trend to higher complication rates and the need for further surgery compared with the results of the treatment of acetabular fractures in younger patients.

Cite this article: Bone Joint J 2014;96-B:157–63.

Introduction

The objective of this study was to determine if a synthetic bone substitute would provide results similar to bone from osteoporotic femoral heads during in vitro testing with orthopaedic implants. If the synthetic material could produce results similar to those of the osteoporotic bone, it could reduce or eliminate the need for testing of implants on bone.

We welcome letters to the Editor concerning articles that have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply.

The October 2013 Hip & Pelvis Roundup³⁶⁰ looks at: Young and impinging; Clothes, weather and femoral heads?; Go long, go cemented; Surgical repair of the abductors?; Aspirin for DVT prophylaxis?; Ceramic-on-polyethylene: a low-wear solution?; ALVAL and ASR™: the story continues….; Salvaging Legg-Calve-Perthes’ disease

Down’s syndrome is associated with a number of musculoskeletal abnormalities, some of which predispose patients to early symptomatic arthritis of the hip. The purpose of the present study was to review the general and hip-specific factors potentially compromising total hip replacement (THR) in patients with Down’s syndrome, as well as to summarise both the surgical techniques that may anticipate the potential adverse impact of these factors and the clinical results reported to date. A search of the literature was performed, and the findings further informed by the authors’ clinical experience, as well as that of the hip replacement in Down Syndrome study group. The general factors identified include a high incidence of ligamentous laxity, as well as associated muscle hypotonia and gait abnormalities. Hip-specific factors include: a high incidence of hip dysplasia, as well as a number of other acetabular, femoral and combined femoroacetabular anatomical variations. Four studies encompassing 42 hips, which reported the clinical outcomes of THR in patients with Down’s syndrome, were identified. All patients were successfully treated with standard acetabular and femoral components. The use of supplementary acetabular screw fixation to enhance component stability was frequently reported. The use of constrained liners to treat intra-operative instability occurred in eight hips. Survival rates of between 81% and 100% at a mean follow-up of 105 months (6 to 292) are encouraging. Overall, while THR in patients with Down’s syndrome does present some unique challenges, the overall clinical results are good, providing these patients with reliable pain relief and good function.

Cite this article: Bone Joint J 2013;95-B, Supple A:41–5.

We have reviewed the current literature to compare the results of surgery aimed to repair or debride a damaged acetabular labrum. We identified 28 studies to be included in the review containing a total of 1631 hips in 1609 patients. Of these studies 12 reported a mean rate of good results of 82% (from 67% to 100%) for labral debridement. Of the 16 studies that reported a combination of debridement and re-attachment, five reported a comparative outcome for the two methods, four reported better results with re-attachment and one study did not find any significant difference in outcomes. Due to the heterogeneity of the studies it was not possible to perform a meta-analysis or draw accurate conclusions. Confounding factors in the studies include selection bias, use of historical controls and high rates of loss of follow-up.

It seems logical to repair an unstable tear in a good quality labrum with good potential to heal in order potentially to preserve its physiological function. A degenerative labrum on the other hand may be the source of discomfort and its preservation may result in persistent pain and the added risk of failure of re-attachment. The results of the present study do not support routine refixation for all labral tears.

Cite this article: Bone Joint J 2014;96-B:24–30.

Hip arthroscopy is particularly attractive in children as it confers advantages over arthrotomy or open surgery, such as shorter recovery time and earlier return to activity. Developments in surgical technique and arthroscopic instrumentation have enabled extension of arthroscopy of the hip to this age group. Potential challenges in paediatric and adolescent hip arthroscopy include variability in size, normal developmental change from childhood to adolescence, and conditions specific to children and adolescents and their various consequences. Treatable disorders include the sequelae of traumatic and sports-related hip joint injuries, Legg–Calve–Perthes’ disease and slipped capital femoral epiphysis, and the arthritic and septic hip. Intra-articular abnormalities are rarely isolated and are often associated with underlying morphological changes.

This review presents the current concepts of hip arthroscopy in the paediatric and adolescent patient, covering clinical assessment and investigation, indications and results of the experience to date, as well as technical challenges and future directions.

We have investigated the benefits of patient specific instrument guides, applied to osteotomies around the knee. Single, dual and triple planar osteotomies were performed on tibias or femurs in 14 subjects. In all patients, a detailed pre-operative plan was prepared based upon full leg standing radiographic and CT scan information. The planned level of the osteotomy and open wedge resection was relayed to the surgery by virtue of a patient specific guide developed from the images. The mean deviation between the planned wedge angle and the executed wedge angle was 0° (-1 to 1, sd 0.71) in the coronal plane and 0.3° (-0.9 to 3, sd 1.14) in the sagittal plane. The mean deviation between the planned hip, knee, ankle angle (HKA) on full leg standing radiograph and the post-operative HKA was 0.3° (-1 to 2, sd 0.75). It is concluded that this is a feasible and valuable concept from the standpoint of pre-operative software based planning, surgical application and geometrical accuracy of outcome.

Cite this article: Bone Joint J 2013;95-B, Supple A:153–8.

The presence of pseudotumours, which are soft-tissue masses relating to the hip, after metal-on-metal hip resurfacing arthroplasty has been associated with elevated levels of metal ions in serum, suggesting that pseudotumours occur when there is increased wear. We aimed to quantify the wear in vivo of implants revised for pseudotumours (eight) and of a control group of implants (22) revised for other reasons of failure.

We found that the implant group with pseudotumours had a significantly higher rate of median linear wear of the femoral component at 8.1 μm/year (2.75 to 25.4) than the 1.79 μm/year (0.82 to 4.15; p = 0.002) of the non-pseudotumour group. For the acetabular component a significantly higher rate of median linear wear of 7.36 μm/year (1.61 to 24.9) was observed in the pseudotumour group compared with 1.28 μm/year (0.81 to 3.33, p = 0.001) in the other group. Wear of the acetabular component in the pseudotumour group always involved the edge of the implant, indicating that edge-loading had occurred.

Our findings are the first direct evidence that pseudotumour is associated with increased wear at the metal-on-metal articulation. Furthermore, edge-loading with the loss of fluid-film lubrication may be an important mechanism of generation of wear in patients with a pseudotumour.

Objectives

We aimed to determine the effect of surgical approach on the histology of the femoral head following resurfacing of the hip.

We have undertaken a prospective, randomised study to compare conservation of acetabular bone after total hip replacement and resurfacing arthroplasty of the hip. We randomly assigned 210 hips to one of the two treatment groups. Uncemented, press-fit acetabular components were used for both.

No significant difference was found in the mean diameter of acetabular implant inserted in the groups (54.74 mm for total hip replacement and 54.90 mm for resurfacing arthroplasty). In seven resurfacing procedures (6.8%), the surgeon used a larger size of component in order to match the corresponding diameter of the femoral component.

With resurfacing arthroplasty, conservation of bone is clearly advantageous on the femoral side. Our study has shown that, with a specific design of acetabular implant and by following a careful surgical technique, removal of bone on the acetabular side is comparable with that of total hip replacement.

We investigated differences in the location and mode of labral tears between dysplastic hips and hips with femoroacetabular impingement (FAI). We also investigated the relationship between labral tear and adjacent cartilage damage. We retrospectively studied 72 symptomatic hips (in 68 patients: 19 men and 49 women) with radiological evidence of dysplasia or FAI on high-resolution CT arthrography. The incidence and location of labral tears and modes of tear associated with the base of the labrum (Mode 1) or body of the labrum (Mode 2) were compared among FAI, mildly dysplastic and severely dysplastic hips. The locations predominantly involved with labral tears were different in FAI and mild dysplastic hips (anterior and anterosuperior zones) and in severely dysplastic hips (anterosuperior and superior zones) around the acetabulum. Significant differences were observed in the prevalence of Mode 1 versus Mode 2 tears in FAI hips (72% (n = 13) vs 28% (n = 5)) and severe dysplastic hips (25% (n = 2) vs 75% (n = 6)). The frequency of cartilage damage adjacent to Mode 1 tears was significantly higher (42% (n = 14)) than that adjacent to Mode 2 tears (14% (n = 3)).

Hip pathology is significantly related to the locations and modes of labral tears. Mode 1 tears may be a risk factor for the development of adjacent acetabular cartilage damage.

Cite this article: Bone Joint J 2013;95-B:1320–5.

Orientation of the acetabular component influences wear, range of movement and the incidence of dislocation after total hip replacement (THR). During surgery, such orientation is often referenced to the anterior pelvic plane (APP), but APP inclination relative to the coronal plane (pelvic tilt) varies substantially between individuals. In contrast, the change in pelvic tilt from supine to standing (dPT) is small for nearly all individuals. Therefore, in THR performed with the patient supine and the patient’s coronal plane parallel to the operating table, we propose that freehand placement of the acetabular component placement is reliable and reflects standing (functional) cup position. We examined this hypothesis in 56 hips in 56 patients (19 men) with a mean age of 61 years (29 to 80) using three-dimensional CT pelvic reconstructions and standing lateral pelvic radiographs. We found a low variability of acetabular component placement, with 46 implants (82%) placed within a combined range of 30° to 50° inclination and 5° to 25° anteversion. Changing from the supine to the standing position (analysed in 47 patients) was associated with an anteversion change < 10° in 45 patients (96%). dPT was < 10° in 41 patients (87%). In conclusion, supine THR appears to provide reliable freehand acetabular component placement. In most patients a small reclination of the pelvis going from supine to standing causes a small increase in anteversion of the acetabular component.

Cite this article: Bone Joint J 2013;95-B:1326–31.

Version of the femoral stem is an important factor influencing the risk of dislocation after total hip replacement (THR) as well as the position of the acetabular component. However, there is no radiological method of measuring stem anteversion described in the literature. We propose a radiological method to measure stem version and have assessed its reliability and validity. In 36 patients who underwent THR, a hip radiograph and CT scan were taken to measure stem anteversion. The radiograph was a modified Budin view. This is taken as a posteroanterior radiograph in the sitting position with 90° hip flexion and 90° knee flexion and 30° hip abduction. The angle between the stem-neck axis and the posterior intercondylar line was measured by three independent examiners. The intra- and interobserver reliabilities of each measurement were examined. The radiological measurements were compared with the CT measurements to evaluate their validity. The mean radiological measurement was 13.36° (sd 6.46) and the mean CT measurement was 12.35° (sd 6.39) (p = 0.096). The intra- and interobserver reliabilities were excellent for both measurements. The radiological measurements correlated well with the CT measurements (p = 0.001, r = 0.877). The modified Budin method appears reliable and valid for the measurement of femoral stem anteversion.

Cite this article: Bone Joint J 2013;95-B:877–80.

We compared the medium-term clinical and radiological results of hybrid total hip replacement (THR) with metal-on-metal Birmingham hip resurfacing (BHR) in two groups of 54 young patients matched for age, gender, body mass index and pre-operative levels of activity.

The clinical outcome was assessed by the University of California, Los Angeles (UCLA) activity score, the Oxford Hip Score (OHS) and the EuroQol scores. Radiologically, all hips were assessed for migration and osteolysis, the hybrid THRs for polyethylene wear and the BHRs for a pedestal sign. The mean follow-up of the patients with a hybrid THR was ten years and for those with a BHR, nine years. Four patients with a hybrid THR and one with a BHR had died. In each group five were lost to follow-up. The revision rate of the hybrid THRs was 16.7% (9 of 54) and of the BHRs 9.3% (5 of 54) (p = 0.195). Radiographs of a further eight hybrid THRs demonstrated wear and osteolysis, and they await revision (p = 0.008). Of the unrevised BHRs 90% had radiological changes, of which approximately 50% had progressed over the previous four years. All hybrid THRs demonstrated linear polyethylene wear with a mean of 1.24 mm (0.06 to 3.03). The BHRs recorded superior OHS (p = 0.013), UCLA (p = 0.008), and EuroQol visual analogue scores (p = 0.009).

After nine years, patients with BHRs remained more active and had a lower rate of revision than those with hybrid THRs. Both groups demonstrated progressive radiological changes at medium-term follow-up.

We report a multicentre prospective consecutive study assessing the long-term outcome of the proximally hydroxyapatite (HA)-coated ABG II monobloc femoral component in a series of 1148 hips in 1053 patients with a mean age at surgery of 64.77 years (22 to 80) at a mean follow-up of 10.84 years (10 to 15.25). At latest follow-up, the mean total Harris hip score was 94.7 points (sd; 6.87; 49 to 100), and the mean Merle d’Aubigné–Postel score was 17.6 points (sd 1.12; 7 to 18). The mean total Engh radiological score score was 21.54 (sd 5.77; 3.5 to 27), with 95.81% of ‘confirmed ingrowth’, according to Engh’s classification. With aseptic loosening or pain as endpoints, three AGB II stems (0.26%) failed, giving a 99.7% survival rate (se 0.002; 95% confidence interval (CI) 0.994 to 1) at 14 years’ follow-up. The survival of patients ≤ 50 years of age (99.0% (se 0.011; 95% CI 0.969 to 1)) did not differ significantly from those of patients aged > 50 years (99.8% (se 0.002; 95% CI 0.994 to 1)). This study confirmed the excellent long-term results currently achieved with the ABG II proximally HA-coated monobloc stem.

Cite this article: Bone Joint J 2013;95-B:1610–16.