The primary treatment goal for patients with femoroacetabular impingement syndrome, a common hip condition in athletes, is to improve pain and function. In selected patients, in the short term following intervention, arthroscopic hip surgery is superior to a pragmatic NHS- type physiotherapy programme. Here, we report the three-year follow-up results from the FemoroAcetabular Impingement Trial (FAIT), comparing arthroscopic hip surgery with physiotherapy in the management of patients with femoroacetabular impingement (FAI) syndrome.

Two-group parallel, assessor-blinded, pragmatic randomised controlled study across seven NHS England sites. 222 participants aged 18 to 60 years with FAI syndrome confirmed clinically and radiologically were randomised (1:1) to receive arthroscopic hip surgery (n = 112) or physiotherapy and activity modification (n = 110). We previously reported on the hip outcome score at eight months. The primary outcome measure of this study was minimum Joint Space Width (mJSW) on Anteroposterior Radiograph at 38 months post randomisation. Secondary outcome measures included the Hip Outcome Score and Scoring Hip Osteoarthritis with MRI (SHOMRI) score.

Minimum Joint Space Width data were available for 101 participants (45%) at 38 months post randomisation. Hip outcome score and MRI data were available for 77% and 62% of participants respectively. mJSW was higher in the arthroscopy group (mean (SD) 3.34mm (1.01)) compared to the physiotherapy group (2.99mm (1.33)) at 38 months, p=0.017, however this did not exceed the minimally clinically important difference of 0.48mm. SHOMRI score was significantly lower in the arthroscopy group (mean (SD) 9.22 (11.43)) compared to the physiotherapy group (22.76 (15.26)), p-value <0.001. Hip outcome score was higher in the arthroscopy group (mean (SD) 84.2 (17.4)) compared with the physiotherapy group (74.2 (21.9)), p-value < 0.001).

Patients with FAI syndrome treated surgically may experience slowing of osteoarthritisprogression and superior pain and function compared with patients treated non- operatively.

Dual mobility (DM) is most often used by surgeons to reduce instability in high risk patients. NJR data on DM has not demonstrated a reduction in all cause revision and has reported an increase in revision for peri-prosthetic fracture (PPF). The aim of our study was:

Prospective F/U of a DM implant since 2016 and enrolled into Beyond Compliance (BC). Primary outcome measure all-cause revision with secondary outcome including any re-operation and Oxford Hip Score (OHS). All patients were risk stratified and considered high risk for instability. Complications were identified via hospital records, clinical coding linkage, NJR and BC. Benchmarking data for comparison was obtained from same data sources we also considered all B type PPF that occurred with cemented polished taper stem (PTS).

159 implants in 154 patients with a mean age 74.0 years and a maximum F/U of 6.7 years. Survivorship for all-cause revision 99.4% (95% CI 96.2–99.8). One femoral only revision. Mean gain in OHS 27.4. Dislocation rate 0.6% with a single event. Patients with a PTS rate of Type B PPF 2.1% requiring revision/fixation. Compared to cTHA this cohort was significantly older (74.0 vs 68.3 years), more co-morbidity (ASA 3 46.5% vs 14.4%) and more non-OA indications (32.4% vs 8.5%). Relative risks for dislocation 0.57 (95%CI 0.08–4.1) and PPF 1.75 (95%CI 0.54–5.72). Every patient had at least one risk factor for falling and >50% of cohort had 4 or more risk factors using NICE tool.

The selective use of DM in high-risk patients can reduce the burden of instability. These individuals are very different to the “average” THA patient. A “perfect storm” is created using a high-risk implant combination (DM & PTS) in high-risk falls risk population. This re-enforces the need to consider all patient and implant factors when deciding bearing selection.

Cemented total hip replacement (THR) provides excellent outcomes and is cost-effective. Polished taper-slip (PTS) stems demonstrate successful results and have overtaken traditional composite-beam (CB) stems. Recent reports indicate they are associated with a higher risk of postoperative periprosthetic femoral fracture (PFF) compared to CB stems. This study evaluates risk factors influencing fracture characteristics around PTS and CB cemented stems.

Data were collected for 584 PFF patients admitted to eight UK centres from 25/05/2006-01/03/2020. Radiographs were assessed for Unified Classification System (UCS) grade and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) type. Statistical comparisons investigated relationships by age, gender, and stem fixation philosophy (PTS versus CB). The effect of multiple variables was estimated using multinomial logistic regression to estimate odds ratios (OR) with 95% confidence intervals (CI).

Median (IQR) age was 79.1 (72.0–86.0) years, 312 (53.6%) patients were female, and 495 (85.1%) stems were PTS. The commonest UCS grade was type B1 (278, 47.6%). The commonest AO/OTA type was spiral (352, 60.3%). Metaphyseal-split fractures occurred only with PTS stems with an incidence of 10.1%. Male gender was associated with a five-fold reduction in odds of a type C fracture (OR 0.22, 95% CI 0.12 to 0.41, p<0.001) compared to a type B fracture. CB stems were associated with significantly increased odds of transverse fracture (OR 9.51, 95% CI 3.72 to 24.34, p <0.001) and wedge fracture (OR 3.72, 95% CI 1.16 to 11.95, p <0.05) compared to PTS stems.

This is the largest study investigating PFF characteristics around cemented stems. The commonest fracture types are B1 and spiral fractures. PTS stems are exclusively associated with metaphyseal-split fractures, but their incidence is low. Males have lower odds of UCS grade C fractures compared to females. CB stems had higher odds of bending type fractures (transverse and wedge) compared to PTS stems. Biomechanical testing is needed for validation and investigation of modifiable factors which may reduce the risk of unstable fracture patterns requiring complex revision surgery over internal fixation.

Aims

The aim of this prospective cohort study was to evaluate the early migration of the TriFit cementless proximally coated tapered femoral stem using radiostereometric analysis (RSA).

Background

Cam morphology develops during adolescence and predisposes individuals to future hip pain and osteoarthritis. An improved understanding of cam development is required to determine whether the process is modifiable.

Aims

The aim of this study was to determine the stability of a new short femoral stem compared with a conventional femoral stem in patients undergoing cementless total hip arthroplasty (THA), in a prospective randomized controlled trial using radiostereometric analysis (RSA).

Background

Short bone-conserving femoral stem implants were developed to achieve more physiological, proximal bone loading than conventional femoral stems. Concerns have arisen, however, that improved loading may be offset by lower primary stability because of the reduced potential area for bony contact.

Introduction

Registry data from around the world demonstrates instability following primary THA is a leading indication for revision. However, the burden of THA dislocation is poorly documented and is not routinely recorded or reported at a national level. Our aim was to determine the rate of dislocation following primary THA in contemporary practice and in doing so determining the burden of THA dislocation to the NHS in Wales.

Aims

The aim of this study was to determine whether patients with metal-on-metal (MoM) arthroplasties of the hip have an increased risk of cardiac failure compared with those with alternative types of arthroplasties (non-MoM).

Aims

The aim of this study was to examine the real time in vivo kinematics of the hip in patients with cam-type femoroacetabular impingement (FAI).

Image-guided intra-articular hip injection of local-anaesthetic and steroid is commonly used in the management of hip pain. It can be used as a diagnostic and/or therapeutic tool and is of low cost (£75). The aim of this study was to assess how often a hip injection has a therapeutic effect.

This is a retrospective, consecutive, case series of intra-articular hip injections performed in a tertiary referral hospital over a 2-year period (2013–4). Patients were identified from the radiology department's prospectively entered database. Clinical information, reason for injection and subsequent management was obtained from hospital records. All patients prospectively reported their pain levels in a numeric pain scale diary (out of 10) at various time points; pre-, immediately post-, 1st day-, 2nd day- and 2 weeks- post-injection. Only patients with complete pain scores at all time points were included (n=200, of the 250 injections performed over study period, 80%).

The majority of injections were performed for osteoarthritis (OA) treatment (82%). The pain was significantly reduced from a pre-injection score of 7.5 (SD:2) to 5.0 (SD:3) immediately post-injection(p<0.001); only 24 (11%) reported any worsening of pain immediately post-injection. Pain significantly reduced further to 3.8(SD:3) at 2-weeks post-injection (p<0.001). 50% of patients had at least a 3 point drop in reported pain. No improvement was seen in 18 patients and 10 (5%) reported worse pain at 2-weeks compared to pre-injection. Of the OA cohort, 10% have required repeat injections, 45% required no further intervention and 45% underwent or are due for hip replacement. No immediate complications occurred.

Intra-articular hip injection reduced pain in 86% of cases and has delayed any further surgical treatment for at least 2 years in over 50% of OA cases. It is hence a cost-effective treatment modality. Further work is necessary to describe factors predicting response.

Objectives

High failure rates of metal-on-metal hip arthroplasty implants have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices. The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage. We aimed to identify validated surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty (THA).

Introduction

The value of Debridement-Antibiotics-and-Implant-Retention (DAIR) in prosthetic-joint-infection (PJI) is still a matter of debate as most studies to-date are underpowered with variable end-points. In our, tertiary referral, bone infection unit we consider DAIR to be a suitable option in all PJIs with soundly fixed prostheses, despite chronicity. The aims of this study were to define the long-term outcome following DAIR in hip PJI and identify factors that influence it.

Periprosthetic femoral fracture (PFF) is a potentially devastating complication after total hip arthroplasty, with historically high rates of complication and failure because of the technical challenges of surgery, as well as the prevalence of advanced age and comorbidity in the patients at risk.

This study describes the short-term outcome after revision arthroplasty using a modular, titanium, tapered, conical stem for PFF in a series of 38 fractures in 37 patients.

The mean age of the cohort was 77 years (47 to 96). A total of 27 patients had an American Society of Anesthesiologists grade of at least 3. At a mean follow-up of 35 months (4 to 66) the mean Oxford Hip Score (OHS) was 35 (15 to 48) and comorbidity was significantly associated with a poorer OHS. All fractures united and no stem needed to be revised. Three hips in three patients required further surgery for infection, recurrent PFF and recurrent dislocation and three other patients required closed manipulation for a single dislocation. One stem subsided more than 5 mm but then stabilised and required no further intervention.

In this series, a modular, tapered, conical stem provided a versatile reconstruction solution with a low rate of complications.

Cite this article: Bone Joint J 2015;97-B:1031–7.

Aims

Femoroacetabular Junction Impingement (FAI) describes abnormalities in the shape of the femoral head–neck junction, or abnormalities in the orientation of the acetabulum. In the short term, FAI can give rise to pain and disability, and in the long-term it significantly increases the risk of developing osteoarthritis. The Femoroacetabular Impingement Trial (FAIT) aims to determine whether operative or non-operative intervention is more effective at improving symptoms and preventing the development and progression of osteoarthritis.

Objectives

The number of surgical procedures performed each year to treat femoroacetabular impingement (FAI) continues to rise. Although there is evidence that surgery can improve symptoms in the short-term, there is no evidence that it slows the development of osteoarthritis (OA). We performed a feasibility study to determine whether patient and surgeon opinion was permissive for a Randomised Controlled Trial (RCT) comparing operative with non-operative treatment for FAI.

Plasma levels of cobalt and chromium ions and Metal Artefact Reduction Sequence (MARS)-MRI scans were performed on patients with 209 consecutive, unilateral, symptomatic metal-on-metal (MoM) hip arthroplasties. There was wide variation in plasma cobalt and chromium levels, and MARS-MRI scans were positive for adverse reaction to metal debris (ARMD) in 84 hips (40%). There was a significant difference in the median plasma cobalt and chromium levels between those with positive and negative MARS-MRI scans (p < 0.001). Compared with MARS-MRI as the potential reference standard for the diagnosis of ARMD, the sensitivity of metal ion analysis for cobalt or chromium with a cut-off of > 7 µg/l was 57%. The specificity was 65%, positive predictive value was 52% and the negative predictive value was 69% in symptomatic patients. A lowered threshold of > 3.5 µg/l for cobalt and chromium ion levels improved the sensitivity and negative predictive value to 86% and 74% but at the expense of specificity (27%) and positive predictive value (44%).

Metal ion analysis is not recommended as a sole indirect screening test in the surveillance of symptomatic patients with a MoM arthroplasty. The investigating clinicians should have a low threshold for obtaining cross-sectional imaging in these patients, even in the presence of low plasma metal ion levels.

We have evaluated the difference in the migration patterns over two years of two cementless stems in a randomised, controlled trial using radiostereophotogrammetric analysis (RSA). The implants studied were the Furlong HAC stem, which has good long-term results and the Furlong Active stem, which is a modified version of the former designed to minimise stress concentrations between the implant and bone, and thus to improve fixation.

A total of 23 Furlong HAC and 20 Furlong Active stems were implanted in 43 patients. RSA examinations were carried out immediately post-operatively and at six, 12 and 24 months post-operatively.

The subsidence during the first year in the Furlong HAC stem, was approximately one-third that of the Furlong Active stem, the measured mean subsidence of the femoral head at six months being 0.27 mm (95% confidence interval (CI) 0.03 to 0.51) and 0.99 mm (95% CI 0.38 to 1.60), respectively (p = 0.03). One Active stem continued to subside during the second year. All hips, regardless of the type of stem were clinically successful as judged by the Oxford hip score and a derived pain score without any distinction between the two types of stem.

The initial stability of the Furlong Active stem was not as good as the established stem which might compromise osseo-integration to the detriment of long-term success. The changes in the geometry of the stem, to minimise stress have affected the attainment of initial stability.

Pseudotumours are a rare complication of hip resurfacing. They are thought to be a response to metal debris which may be caused by edge loading due to poor orientation of the acetabular component. Our aim was to determine the optimal acetabular orientation to minimise the risk of pseudotumour formation.

We matched 31 hip resurfacings revised for pseudotumour formation with 58 controls who had a satisfactory outcome from this procedure. The radiographic inclination and anteversion angles of the acetabular component were measured on anteroposterior radiographs of the pelvis using Einzel-Bild-Roentgen-Analyse software. The mean inclination angle (47°, 10° to 81°) and anteversion angle (14°, 4° to 34°) of the pseudotumour cases were the same (p = 0.8, p = 0.2) as the controls, 46° (29° to 60°) and 16° (4° to 30°) respectively, but the variation was greater. Assuming an accuracy of implantation of ± 10° about a target position, the optimal radiographic position was found to be approximately 45° of inclination and 20° of anteversion. The incidence of pseudotumours inside the zone was four times lower (p = 0.007) than outside the zone.

In order to minimise the risk of pseudotumour formation we recommend that surgeons implant the acetabular component at an inclination of 45° (± 10) and anteversion of 20° (± 10) on post-operative radiographs. Because of differences between the radiographic and the operative angles, this may be best achieved by aiming for an inclination of 40° and an anteversion of 25°.

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.