Early failure associated with adverse reactions to metal debris is an emerging problem after hip resurfacing but the exact mechanism is unclear. We analysed our entire series of 660 metal-on-metal resurfacings (Articular Surface Replacement (ASR) and Birmingham Hip Resurfacing (BHR)) and large-bearing ASR total hip replacements, to establish associations with metal debris-related failures. Clinical and radiological outcomes, metal ion levels, explant studies and lymphocyte transformation tests were performed. A total of 17 patients (3.4%) were identified (all ASR bearings) with adverse reactions to metal debris, for which revision was required. This group had significantly smaller components, significantly higher acetabular component anteversion, and significantly higher whole concentrations of blood and joint chromium and cobalt ions than asymptomatic patients did (all p < 0.001). Post-revision lymphocyte transformation tests on this group showed no reactivity to chromium or cobalt ions. Explants from these revisions had greater surface wear than retrievals for uncomplicated fractures. The absence of adverse reactions to metal debris in patients with well-positioned implants usually implies high component wear. Surgeons must consider implant design, expected component size and acetabular component positioning in order to reduce early failures when performing large-bearing metal-on-metal hip resurfacing and replacement

Dual-taper implants provide surgeons with options to optimise patients' anatomy intraoperatively but are at risk of early revision due to adverse tissue reactions to corrosion debris. Risk factors for failure and linkage with symptoms however are not fully understood. We related retrieval findings to clinical and implant variables.

This study involved 88 failed dual-taper implants with TMZF femoral stems and cobalt-chromium necks, revised for pain, elevated Co (median = 7.3μg/L) and Cr (median = 2.15μg/L) ions levels and fluid collection on MRI.

Stem-neck surfaces were assessed for: 1) severity of corrosion using a published visual method and 2) severity of material lost and location of damage with a roundness-measuring machine. Five traces were taken on each round section of the taper surface at 45° increments to compute the relative depth of damage. The total area of these traces provided a measure of surface damage for comparative purposes.

The stem-neck taper junctions were severely corroded; the deepest areas of damage were on the inferior-proximal and superior-distal part of the necks, compatible with cantilever bending. Elemental analysis revealed chromium rich deposits indicative of corrosion processes and metal transfer from the stem to the neck.

There was a positive correlation between the severity of damage and time of implantation (p<0.0001). Co and Cr levels in the blood were also strongly correlated (p<0.0001, p=0.0002). No other implant or patient variables were linked.

The stem-neck junction was severely corroded in all cases. The severity and location of the areas of surface damage did not link with implant or patient characteristics in this big cohort suggesting that the design and material combination is the predominant source of failure in these designs.

Dual-taper hips are severely corroded at the stem-neck junction; this appears to be due to the use of a TMZF alloy stem paired with CoCrMo necks.

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.

The rate and mode of early failure in 463 Birmingham hip resurfacings in a two-centre, multisurgeon series were examined. Of the 463 patients two have died and three were lost to follow-up. The mean radiological and clinical follow-up was for 43 months (6 to 90). We have revised 13 resurfacings (2.8%) including seven for pain, three for fracture, two for dislocation and another for sepsis. Of these, nine had macroscopic and histological evidence of metallosis. The survival at five years was 95.8% (95% confidence interval (CI) 94.1 to 96.8) for revision for all causes and 96.9% (95% CI 95.5 to 98.3) for metallosis. The rate of metallosis related revision was 3.1% at five years. Risk factors for metallosis were female gender, a small femoral component, a high abduction angle and obesity. We do not advocate the use of the Birmingham Hip resurfacing procedure in patients with these risk factors

Aims. Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. Methods. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. ‘Controls’ were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size. Results. Using a previously-reported ALVAL classification, the majority of pseudotumour-positive caseswere found to have intermediate-grade group 2 (n = 10; 63%) or group 3 (n = 4; 25%) histological findings. Two further patients (13%) had high-grade group 4 lesions. HLA-DQB1*05:03:01 (p = 0.0676) and HLA-DRB1*14:54:01 (p = 0.0676) alleles were significantly associated with a higher risk of pseudotumour formation, while HLA-DQA1*03:01:01 (p = 0.0240), HLA-DRB1*04:04:01 (p = 0.0453), HLA-C*01:02:01 (p = 0.0453), and HLA-B*27:05:02 (p = 0.0855) were noted to confer risk reduction. Conclusion. These findings confirm the association between specific HLA genotypes and the risk of pseudotumour development around MoM hip resurfacings. Specifically, the two ‘at risk’ alleles (DQB1*05:03:01 and DRB1*14:54:01) may hold clinical value in preoperative screening and prospective surgical decision-making. Cite this article: Bone Jt Open 2023;4(3):182–187

Aims. Femoral revision component subsidence has been identified as predicting early failure in revision hip surgery. This comparative cohort study assessed the potential risk factors of subsidence in two commonly used femoral implant designs. Methods. A comparative cohort study was undertaken, analyzing a consecutive series of patients following revision total hip arthroplasties using either a tapered-modular (TM) fluted titanium or a porous-coated cylindrical modular (PCM) titanium femoral component, between April 2006 and May 2018. Clinical and radiological assessment was compared for both treatment cohorts. Risk factors for subsidence were assessed and compared. Results. In total, 65 TM and 35 PCM cases were included. At mean follow-up of seven years (1 to 13), subsidence was noted in both cohorts during the initial three months postoperatively (p < 0.001) then implants stabilized. Subsidence noted in 58.7% (38/65 cases) of the TM cohort (mean 2.3 mm, SD 3.5 mm) compared to 48.8% (17/35) of PCM cohort (mean 1.9 mm, SD 2.6 mm; p = 0.344). Subsidence of PCM cohort were significantly associated with extended trochanteric osteotomy (ETO) (p < 0.041). Although the ETO was used less frequently in PCM stem cohort (7/35), subsidence was noted in 85% (6/7) of them. Significant improvement of the final mean Oxford Hip Score (OHS) was reported in both treatment groups (p < 0.001). Conclusion. Both modular TM and PCM revision femoral components subsided within the femur. TM implants subsided more frequently than PCM components if the femur was intact but with no difference in clinical outcomes. However, if an ETO is performed then a PCM component will subside significantly more and suggests the use of a TM implant may be advisable. Cite this article: Bone Joint J 2020;102-B(6):709–715

Aims

Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon.

Aims

The Birmingham Hip Resurfacing (BHR) arthroplasty has been used as a surgical treatment of coxarthrosis since 1997. We present 20-year results of 234 consecutive BHRs performed in our unit.

Aims

In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component.

Aims

The aims of this study were to determine if an increasing serum cobalt (Co) and/or chromium (Cr) concentration is correlated with a decreasing Harris Hip Score (HHS) and Hip disability and Osteoarthritis Outcome Score (HOOS) in patients who received the Articular Surface Replacement (ASR) hip resurfacing arthroplasty (HRA), and to evaluate the ten-year revision rate and show if sex, inclination angle, and Co level influenced the revision rate.

Introduction. In the early 2000s hip resurfacing became an established bone conserving hip arthroplasty option particularly for the fit and active patient cohort. The performance of second-generation metal-on-metal bearings had led to the reintroduction of hip resurfacing. The Birmingham Hip resurfacing (BHR) was introduced in 1997. This was followed by a number of different designs of the hip resurfacing. The Durom hip resurfacing was introduced in 2001. These two designs had different metallurgical properties, design parameters particularly clearance and different implantation techniques. Data from joint registries show that both prosthesis perform well. Objectives. Our objective was to perform a retrospective survival analysis comparing the Birmingham to the Durom hip resurfacing and analyse the mode of failures of the cases revised. Methods. Data was collected prospectively but analysed retrospectively. The two cohorts comprised patients treated by two senior surgeons at different units. The follow up range was 1 to 14 years with a mean of 10 years. The end-point was revision for any cause. However this was further substratified. Results. The outcome of all patients was known. The two cohorts exhibited no significant difference in demographics. No failures in either cohort were attributed to adverse reaction to metal debris. Revision for any cause was analysed by plotting Kaplan-Meier Survival curves. The Durom cohort (n=273) had 5 deaths and 9 revisions. The Birmingham cohort (n=567) had 5 deaths and 22 revisions. The Kaplan-Meier survival curves for the two resurfacing designs were different. The Durom cohort demonstrated a concave curve with more early failures. This was contrary to the BHR's convex curve with higher incidence of late failures. We analysed the data by substratifying into failure of femoral or acetabular component and neck fractures. Conclusions. The Kaplan-Meier survival analysis demonstrates that the Durom hip resurfacings had a higher rate of early failure. However extrapolation of the curves suggests that the Durom may have a superior long term survival compared to the BHR. We postulate that this may be due to the femoral implantation technique with less late failures in Duroms and an apparent acceleration of failures in BHR cohort around the ten year stage. Joint registry data also reflect this pattern

Total hip replacement in patients with advanced osteonecrosis of the femoral head is often complicated by early loosening of the femoral component. Recent evidence has suggested that abnormal bone extending into the proximal femur may be responsible for the early failure of the femoral component. We aimed to identify which patients were at high risk of early failure by evaluating gadolinium-enhanced MR images of histologically-confirmed osteonecrotic lesions beyond the femoral head. Although the MR signal intensity has been shown to correlate well with osteonecrosis in the femoral head, it was found to be relatively insensitive at identifying lesions below the head, with a sensitivity of only 51% and a predictive value of a negative result of only 48%. However, the specificity was 90%, with the predictive value of a positive MRI finding being 86%. Only those patients with osteonecrosis of the femoral head secondary to sickle-cell disease, who are known to be at high risk of early loosening, had changes in the MR signal in the greater trochanter and the femoral shaft. This observation suggests that changes in the MR signal beyond the femoral head may represent osteonecrotic lesions in areas essential for the fixation of the femoral component. Pre-operative identification of such lesions in the neck of the femur may be important when considering hip resurfacing for osteonecrosis of the femoral head, following which early loosening of the femoral component and fracture of the neck are possible complications

Background. The prevalence of immunocompromised patients undergoing Total Hip Arthroplasty (THA) is increasing worldwide as a consequence of advances in treatment. HIV is presenting in an older population group and concerns of higher rates of infection, early failures and dangers posed to healthcare workers exist. This study is imperative to predict future burden of THA and make subsequent provisions. Objectives. The objective was to determine the seroprevalence of HIV in patients presenting for THA in an academic institution in a developing country. Secondarily, the aim was to determine if there is any difference in the seroprevalence of patients undergoing THA and TKA and finally to assess the status of disease control in seropositive patients eligible for TJA on pre-existing HAART. Study Design & Methods. The seroprevalence of HIV in 676 non-haemophilic patients undergoing Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) at a single academic institution was prospectively assessed. All patients undergoing TJA from January 2016 – March 2018 were counselled and offered HIV testing pre-operatively. HIV ELISA tests were performed on all consenting patients awaiting TJA. The CD4+ count and viral load was measured for all HIV-infected patients. Viral load is a strong indicator of good viral suppression and is a positive prognostic factor for the long-term disease outcome. Results. There were 51 patients (14.4%) of 352 patients undergoing THA who were HIV-infected. The seroprevalence of 324 patients undergoing TKA was 5.86%. There were 56 patients (8.2%) who refused HIV testing. Young females (<45 years old) were 6.8 times more likely to refuse testing. Overall, 70 patients (10.3%) of awaiting TJA were HIV-positive Only 14 patients (2%) undergoing TJA were newly diagnosed with HIV-infection. All other patients were already on anti-retroviral therapy. The age of HIV-infected patients awaiting THA (54.56 years) was statistically significantly (p=0.036) younger than patients awaiting TKA (62.45 years). The Body Mass Index (BMI) was significantly lower in THA than TKA (p=0.021). The average CD4+ counts for THA and TKA was 286 (56–854) and 326 (185–1000) respectively. 67% of patients had a viral load less than lower than detectable level (LDL). Of the HIV-infected patients presenting for THA, 34 (67%) had evidence of avascular necrosis (AVN) and 4 (7.84%) with a neck of femur fracture. No HIV-infected patients presenting for TKA had evidence of AVN of the knee. Conclusions. The seroprevalence of HIV in patients undergoing THA is higher than those undergoing TKA and the reported average in the general population. This may reflect the high association between both HIV and HAART and AVN of the hip. Our findings predict a significant burden on arthroplasty services in the future

Pseudotumours have recently been reported in non-metal-on-metal total hip replacements (non-MoM THRs), however the magnitude and risk factors for this complication are unknown, as is the outcome of its treatment. 3340 primary THR undergoing revision for pseudotumour between 2008 and 2015 were identified in the National Joint Registry for England and Wales. 7.5% (n=249) of these pseudotumour revisions, had non-MoM bearing surfaces. The risk of revision for pseudotumour in non-MoM hips was 0.032% (249/789,397; 95% CI 0.028%–0.036%). The risk of pseudotumour revision was 2.35 times (95% CI 1.76–3.11) higher in ceramic-on-ceramic compared with hard-on-soft bearings, and 2.80 times (95% CI 1.74–4.36) higher in 36mm metal-on-polyethylene bearings compared to 28mm and 32mm metal-on-polyethylene bearings. The outcome of revision for pseudotumour non-MoM hips was studied in 185 hips. 13.5% (n=25) had re-revisions at a mean of 1.2 years (range 0.1–3.1 years). Infection (32%), dislocation/subluxation (24%), and aseptic loosening (24%) were the commonest indications for re-revision. The 4-year survival rate was 83.8% (95% CI=76.7%–88.9%). Multiple revision indications (Hazard Ratio (HR)=2.78; 95% CI=1.03–7.49) and incomplete revision procedures (HR=5.76; 95% CI=1.28–25.9) increased the risk of re-revision. Although the overall risk of revision for pseudotumour in non-MoM THRs is low, the risk is increasing and is significantly higher in ceramic-on-ceramic and large head metal-on-polyethylene THR. These revisions have a high early failure rate

Introduction. Ceramic heads are used in hip revision surgery to mitigate corrosion concerns. Manufacturers recommend using a pristine titanium sleeve in conjunction with a well-fixed metal stem to prevent early failure of the ceramic head. However, the influence of impact force, head size, and sleeve offset on pull-off strength and seating displacement of a revision head assembly is not fully understood. Therefore, the purpose of this study was to investigate the pull-off strength and displacement of commercially available revision ceramic heads and titanium taper sleeve offsets (BIOLOX OPTION, CeramTec GmbH, Plochingen, Germany) while covering a range of clinically relevant impaction forces. Methods. Two head sizes (28 mm, n = 12 and 36 mm, n = 12) and two taper adapter sleeve offsets (small, n = 12 and extra-large, n = 12) were tested in this study. A dynamic impaction rig was constructed to seat the head, sleeve, and stem assembly (Fig. 1). Consistent impaction forces were achieved by dropping a hammer fixed to a lever arm from a pre-determined height onto a standard impactor instrumented with a piezoelectric force sensor (PCB Piezotronics Inc.). Axially applied forces of 2 kN and 6 kN were used to cover a range of typical impaction forces. Three non-contact differential variable reluctance transducers (LORD Sensing Systems) were used to track the displacement of the head relative to the stem. Subsequently, samples were transferred to a servo hydraulic testing machine, and a pull-off test was carried out per ISO 7206–10 to measure the disassembly force. Results. For all head and sleeve combinations assembled at 6 kN, pull-off forces and assembly displacements were over two times the values measured at 2 kN. As expected, an increased assembly force resulted in increased pull-offs and displacements. Head size did not play a significant role on measured outcomes. Regarding sleeve offsets, at assembly of 6 kN mean pull-off forces for extra-large sleeves were reduced by approximately 25% relative to small sleeves (Fig 2). However, at a 2 kN assembly, sleeve offsets did not appear to influence pull-off forces. Discussion. This study assessed the effect of impact assembly force, head size, and sleeve offset on pull-off strength and seating displacement of revision ceramic heads. The data suggests assembly force and sleeve offset may influence the pull-off strength and seating displacement of modular heads used in revision hip arthroplasty. Mean pull-off forces for revision heads were comparable in magnitude and trend to previous studies assessing the linear relationship between assembly force and pull-off force in primary heads (Krull et al., 2017, Rehmer et al., 2012). Lower pull-off forces were observed for extra-large sleeves when compared to small sleeves, indicating, decreased contact at the sleeve and stem interface for extra-large offsets may play a role in reducing pull-off forces. Acknowledgment:. The authors would like to thank CeramTec GmbH (Plochingen, Germany) for providing the head, sleeve, and stem implants. For any figures or tables, please contact authors directly

Ceramic on ceramic (CoC) Total Hip Replacement revisions give specific problems and no consensus is made on the way to perform it. The aim of this study was to report the results of THA CoC revisions and to identify the specific concerns. Between April 2007 and May 2016, 50 consecutive revisions have been performed on average 2.8 years after the THA, in 46 patients (28 males, 18 females) at a mean age of 55 years. The main reasons for revision were loosening (34%), pain without loosening (20%), infection (12%), implant breakage (10%), and instability (8%). There were 41 implant revisions, five revisions without implant change (10%) and four revisions for head change (8%). Revisions were performed without bone reconstruction in 68% of hips and with a CoC couple in 83% of hips. Three patients have died and three were lost to follow up. There were six intraoperative femoral fractures, one early and two late non−recurrent dislocations. Eight hips (16%) had re−revision with implant replacement. At a mean follow-up of 5.5 years, the mean PMA, Harris and WOMAC scores were 14.8, 72 and 23. 80% of patients were satisfied of the procedure and 89% were ready to re-do the surgery if necessary. 16% of hips experienced a noise. There were no complete lucent lines, no osteolysis, and no implant migration. Wear was not measurable. The 6-year survival rate was 82 % and 90 % if the end-point was implant revision for any cause and for fixation failure, respectively. CoC THA failure mainly affects a young population and occurs early. Failure is not wear-related but possibly related to inadequate technique. It is often possible to perform THA revision without any bone graft, using standard implants and CoC couple, provided the implants are matched

The early failure and revision of bimodular primary total hip arthroplasty prostheses requires the identification of the risk factors for material loss and wear at the taper junctions through taper wear analysis. Deviations in taper geometries between revised and pristine modular neck tapers were determined using high resolution tactile measurements. A new algorithm was developed and validated to allow the quantitative analysis of material loss, complementing the standard visual inspection currently used. The algorithm was applied to a sample of 27 retrievals (in situ from 2.9 to 38.1 months) of the withdrawn Rejuvenate modular prosthesis. The mean wear volumes on the flat distal neck piece taper was 3.35 mm. 3. (0.55 to 7.57), mainly occurring in a characteristic pattern in areas with high mechanical loading. Wear volume tended to increase with time to revision (r² = 0.423, p = 0.001). Implant and patient specific data (offset, stem size, patient’s mass, age and body mass index) did not correlate with the amount of material loss observed (p >  0.078). Bilaterally revised implants showed higher amounts of combined total material loss and similar wear patterns on both sides. The consistent wear pattern found in this study has not been reported previously, suggesting that the device design and materials are associated with the failure of this prosthesis. Cite this article: Bone Joint J 2015;97-B:1350–7

Aims

The aim of this study was to evaluate the incidence of liner malseating in two commonly used dual-mobility (DM) designs. Secondary aims included determining the risk of dislocation, survival, and clinical outcomes.

Aims

With increasing burden of revision hip arthroplasty (THA), one of the major challenges is the management of proximal femoral bone loss associated with previous multiple surgeries. Proximal femoral arthroplasty (PFA) has already been popularized for tumour surgeries. Our aim was to describe the outcome of using PFA in these demanding non-neoplastic cases.

Aims

Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study.