Ceramic bearing fracture is a rare complication following implantation using modern day ceramic bearing materials. Revision bearing options in such cases is debated, with the choice between ceramic-on-ceramic and ceramic-on-polyethylene bearings. Revision to a hard on soft bearing raises concerns about potential catastrophic wear secondary to a third-body reaction caused by the fractured ceramic particles. Data was collected retrospectively from the NJR, electronic patient records, revision database and picture archiving and communication system. Templating software was used to determine linear wear between first post-operative radiograph and the latest available follow up. Univariate analysis was used to examine patient demographics and the wear rates for revision of ceramic bearing fractures to ceramic on polyethylene components. The intra and inter-rater reliability of wear measurements was calculated. There were twelve patients identified as meeting the inclusion criteria. The average age at revision was 62 years (54–72). There were 6 liner and 6 head fractures revised to delta ceramic heads and cross-linked polyethylene acetabular components. The most frequently used head size was 32mm. At mean follow up of 3.8 years (0.5 6.1 years), median 4.4 years, linear wear rate was calculated at 0.08± 0.06 mm/year. Both intra-rater and inter-rater reliability was excellent with ICC scores of 0.99 at all timepoints. Revision to ceramic on polyethylene (CoP) bearings following ceramic fracture does not cause early catastrophic wear at early follow up. It appears safe to use this hard on soft bearing combination, given that wear rates are comparable to what is expected in a primary hip replacement setting. Longer follow up is required to establish if this trend persists

Introduction. Contact between the femoral head and rim of the acetabular liner in total hip replacements has been linked to adverse tribological performance that may potentially shorten the lifespan of the prosthesis. Predicting the size and location of the contact area can be done computationally, however, experimental validation of these models is challenging due to the conforming nature of the bearing surfaces. This study aimed to develop a method of accurately determining the in-vitro contact area between the femoral head and acetabular cup in metal-on-polyethylene and ceramic-on-polyethylene bearings under different component orientations. Method. Metal-on-polyethylene and ceramic-on-polyethylene samples, with a nominal diameter of 36mm (DePuy Synthes, Leeds, UK), were tested with the cups orientated using a combination of inclination (equivalent to 45°, 55° and 65° in-vivo) and version (−20°, 0°, 20° and 40°) angles. The liners, which were first gold hard-coated (EMSCOPE SC 500, Quarum Technologies, UK), were inserted into a Pinnacle. ®. titanium shell, and femoral heads were mounted on a vertical spigot (Figure 1). A single-station multi-axis electromechanical hip joint simulator (Prosim, Simulator Solutions, UK) was used to position the samples with 18.7° flexion, 6.2° adduction and 8.3° external rotation, congruous with just after heel strike (ISO 14242-1), and apply a 3kN static axial load through the centre of the femoral head. The contact area was generated by manually turning the head about the vertical axis of the centre of rotation of the applied load, removing the gold hard-coating from the contacting areas. The contact area was determined from photographs of the acetabular cup using SolidWorks (Dassault Systèmes, US) and ImageJ (National Institutes of Health, US) software packages. Three repeats under each combination of cup angles were completed, and the mean contact area and 95% confidence limits were determined for each bearing under all cup angle combinations. Results. The metal-on-polyethylene and ceramic-on-polyethylene bearings generated non-spherical, irregular shaped contact areas (Figure 2) ranging between 350mm. 2. and 470mm. 2. when tested under a range of conditions (Figure 3). Total mean contact area decreased significantly with ceramic-on-polyethylene bearings (t-test; p=0.001) and non-significantly in the metal-on-polyethylene bearings (t-test; p=0.68), when tested with 65° compared to 55° of inclination. Version angle had the greatest effect on contact area when combined with 65° of inclination and the least effect when combined with the 45° inclination angle. Evidence of the contact zone reaching the edge of the cup was observed on samples tested with steep inclination angles for both bearing combinations. Discussion. A well-demarcated area in the gold hard-coating was quantifiable using the methods described above, enabling the contact area in conforming hip replacement bearings, with the head and liner centres coincident, to be measured experimentally. The polyethylene liners showed a degree of deformation under load resulting in an irregular-shaped contact area, the size and position of which was affected by cup version and inclination angles. This data can be used to validate contact mechanics computational models

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen. In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern. Cite this article: Bone Joint J 2014; 96-B:868–75

Thirty-nine cementless hip replacements using metal-on-metal articulation were consecutively implanted in thirty patients less than fifty years of age and compared with a matched control group of cementless replacements using ceramic-on-polyethylene articulation. The Harris hip score at follow-up (minimum five years) for the metal-on-metal was 94.9 (range, 74–100). After the same follow-up, the results of the ceramic-on-polyethylene were significantly worse: nine osteolyses and seven surgical revisions related to wear. Five-year survival rates were 97% +/− 2% for the ceramic-on-polyethylene and 100% for the metal-on-metal. The metal-on-metal may be recommended to prevent wear problems in younger and more active patients. The aim of the current study was to assess the results of metal-on-metal articulating components inserted as a primary hip replacement in patients under the age of fifty, comparated with a matched control group using ceramic-on-polyethylene. Patients and methods. The inclusion of patients was: under fifty years of age and a diagnosis of arthrosis or necrosis of the femoral head. Femoral stem and cup migration was detected. A variation over five millimeters between the follow-up radiographs was considered as migration. At the follow-up in 2003, the cobalt concentrations in the whole blood were assessed in the metal-on-metal cohort. The detection limit of cobalt in the whole blood was 0.06 μg/L. None of the components had migration. At a mean follow-up of sixty-nine months, the median concentration of cobalt in the whole blood was 0.62μg/L. Only eight patients had cobalt levels greater than 1 μg/L. Considering a reoperation with the exchange of one of the components as end point, the five year survival rates were 100% for the metal-on-metal group and 97% + 2 for the ceramic-on-polyethylene group. Our study suggests that the metal-on-metal articulation gives a significant improvement in terms of resistance to wear when compared with these conventional bearing components. Our results suggest the metal-on-metal articulation with cementless components can be recommended in the young and active patient to prevent the occurrence of wear and osteolysis. A careful assessment of patients with high levels of whole-blood cobalt should be performed. Funding: Aucun

Aims. Dislocation is a major concern following total hip arthroplasty (THA) for osteoarthritis (OA). Both dual-mobility components and standard acetabular components with large femoral heads are used to reduce the risk of dislocation. We investigated whether dual-mobility components are superior to standard components in reducing the two-year dislocation and revision risk in a propensity-matched sample from the Danish Hip Arthroplasty Register (DHR). Methods. This population-based cohort study analyzed data from the DHR and the Danish National Patient Register. We included all patients undergoing primary THA for OA from January 2010 to December 2019 with either dual-mobility or standard acetabular components with metal-on-polyethylene or ceramic-on-polyethylene articulations with a 36 mm femoral head. The samples were propensity score-matched on patient and implant characteristics. The primary outcome was the difference in the absolute risk of dislocation within two years, with a secondary outcome of the difference in the absolute risk of revision surgery of any cause within the same timeframe. The cumulative incidence of dislocation was calculated using the Aalen-Johansen estimator, while the difference in absolute risk was estimated using absolute risk regression (ARR). Results. We included 4,499 patients with dual-mobility components and 4,499 patients with standard components after propensity score-matching. Both groups had a mean age of 75 years (SD 8.5), included approximately 60% females, and had a two-year survival of 95.3% (95% CI 94.6 to 95.9). The dual-mobility group was 80% less likely to dislocate within two years (ARR 0.20 (95% CI 0.14 to 0.28); p < 0.001), with no significant difference in the risk of revision compared to standard components (ARR 1.15 (95% CI 0.89 to 1.48); p = 0.293). Conclusion. Dual-mobility components are associated with a reduced risk of dislocation and with no significant difference in the risk of revision for any cause within two years of THA when compared to standard acetabular components with 36 mm femoral heads. Cite this article: Bone Joint J 2025;107-B(1):50–57

To improve the longevity of total hip replacements (THR), it is necessary to prevent wear of the ultra-high molecular weight polyethylene (UHMWPE) bearing, as wear debris can cause osteolysis and aseptic loosening. Highly cross-linked UHMWPE reduces wear, sometimes stabilized with vitamin E to preserve its mechanical properties and prevent oxidative degeneration. An extra novel solution has been grafting the surface of UHMWPE with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). This treatment uses a hydrophilic (wettable) phospholipid polymer to improve lubrication and reduce friction and wear of the bearing material. We set out to test the wear and friction of ceramic-on-polyethylene (COP) THRs that had the PMPC surface treatment, or left untreated for control. Four groups of UHMWPE bearings were tested against identical 40mm ceramic heads (zirconia-toughened alumina). The UHMWPE bearings were highly cross-linked with/without vitamin E (HXL Vit. E: 125 kGy radiation dose / HXL: 75 kGy). In each group, half underwent the PMPC treatment (n = 3 for all four groups). Testing was conducted on an AMTI hip simulator for 10 million walking cycles of ISO-14242-1, at 1 Hz, with diluted bovine serum (30 g/L protein concentration) as lubricant, at 37ºC, and with fluid absorption errors corrected with active soak controls. Using a previously published method, frictional torques and a frictional factor around three orthogonal axes about the femoral head were measured/computed, by data processing of the measurements of a 6-DOF load cell on each station of the hip simulator. Such friction measurements and stops for specimen weighing were carried out at regular intervals throughout the wear test. The HXL liners without and with the PMPC treatment wore at 5.86±0.402 mg/Mc and 1.70±1.36 mg/Mc, respectively (p=0.013) (Fig. 1). The HXL Vit. E liners without and with the PMPC treatment wore at 2.14±0.269 mg/Mc and 0.736±0.750 mg/Mc, respectively (p=0.035). The wear rates of the untreated HXL and HXL Vit. E liners were significantly different (p=0.0002) but no difference in wear rate was found between the two PMPC treated groups (p=0.179), although, as mentioned above, the PMPC treatment very significantly reduced wear in each case. The ceramic femoral heads showed little wear (weight loss) themselves. In general, the THRs showed decreasing friction over the 10 Mc, with the PMPC types showing a slight increase in friction towards the end of the test (Fig. 2). PMPC HXL liners showed the lowest friction factor (0.022±0.001) which was significantly lower (p<0.001) than the friction of the untreated liners (0.028±0.002) (Fig. 3). The PMPC HXL Vit. E liners showed lower friction factors than the untreated HXL Vit. E liners (0.034±0.002, 0.036±0.004, respectively), although this difference was not significant (p=0.116). Overall, the liners with the PMPC treatment displayed statistically significantly lower friction factors (p=0.003) than those untreated. The coincidence of some reduction of surface friction with larger wear reduction obviously suggests some but not necessarily full causality. PMPC successfully reduced both the friction and the wear in these COP THRs during this extended 10 Mc test. This likely would translate to improved implant longevity in patients. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

We report on an innovative surface grafting to highly crosslinked (HXLPE) bearing for THA using a biocompatible-phospholipid-polymer poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC). Such hydrophilic surfaces mimic articular cartilage and are hypothesized to improve lubrication and thereby reduce friction and wear. We performed in vitro testing of wear and friction of ceramic-on-polyethylene THRs with the PMPC treatment, and compared them with untreated controls. Highly cross-linked UHMWPE bearings, gamma-ray-irradiated at different levels with and without vitamin E (HXL Vit. E: 125 kGy, HXL: 75 kGy, respectively) were divided so half were PMPC treated (n=3 for all four groups). All were paired with identical 40 mm diameter zirconia-toughened-alumina ceramic heads. Testing was carried-out on an AMTI hip simulator for 10 million simulated walking cycles with standard lubricant and conditions (ISO-14242-1). Wear was measured gravimetrically at 21 intervals, and so was frictional torque with a previously described and tested methodology. PMPC treatment produced a statistically significant 71% in wear reduction of HXL poly (1.70±1.36 mg/Mc for PMPC vs. 5.86±0.402 mg/Mc for controls, p=0.013). A similar significant wear reduction was found for PMPC treated HXL with Vit. E liners (0.736±0.750 mg/Mc, vs. 2.14±0.269 mg/Mc, p=0.035). The improvements were associated with 12% and 5% reductions in friction of the HXL and Vit. E HXL respectively (statistically significant p=0.003, and marginal p=0.116, one tailed). These results were an important step in the quest for lower wearing, thin and strong UHMWPE liners for larger diameter femoral heads with the potential benefit of longevity and less risk of dislocation after surgery

Introduction. The performance of total hip replacement (THR) devices can be affected by the quality of the tissues surrounding the joint or the mismatch of the component centres during hip replacement surgery. Experimental studies have shown that these factors can cause the separation of the two components during walking cycle (dynamic separation) and the contact of the femoral head with the rim of the acetabular liner (edge loading), which can lead to increased wear and shortened implant lifespan. 1. There is a need for flexible pre-clinical testing tools which allow THR devices to be assessed under these adverse conditions. In this work, a novel dynamic finite element model was developed that is able to generate dynamic separation as it occurs during the gait cycle. In addition, the ability to interrogate contact mechanics and material strain under separation conditions provides a unique means of assessing the severity of edge loading. This study demonstrates these model capabilities for a range of simulated surgical translational mismatch values, for ceramic-on-polyethylene implants. Methodology. The components of the THR were aligned and constrained as illustrated in Figure 1. CAD models of commercially available implant geometries were used (DePuy Synthes, Leeds, UK) modified for model simplicity by removing anti-rotation features. The polyethylene cup liner was given elastic-plastic behaviour. An axial load following the Paul cycle pattern (5 repetitive cycles) with maximum of 3KN and swing phase load of 0.3KN, was applied through the cup holder. The effect of translational mismatch was implemented by using a spring element connected to the cup unit on the lateral side. The spring was compressed by a fixed amount to replicate a degree of medial-lateral mismatch of the components. The instantaneous resultant force vector dictated the dynamic sliding behaviour of the cup against the head. In this study, translational medial-lateral mismatch values of 1, 2, 3 and 4mm were used and the medial-lateral dynamic separation, contact pressure maps and plastic strain were recorded. Results. The highest level of dynamic separation is achieved when the minimum axial load (during swing phase) is applied. The dynamic separation increases as the surgical translation mismatch increases (figure 2), with values over 0.5mm (radial clearance) representing cases where the head is in contact with the rim of the cup. Maximum separation occurred towards the end of the swing phase. Plots of the shape of the contact pressure at that point can be seen in Figure 3. Only the 4mm mismatch created substantial plastic deformation. Conclusion. The finite element model was able to predict medial-lateral separation as it occurred dynamically in the gait cycle, including cases where the femoral head was in contact with the rim of the cup. The increase in medial-lateral separation with increased translational mismatch was in broad agreement with existing experimental data. 2. Substantial plastic deformation was only seen in cases where the translational mismatch caused the femoral head to be in contact with the rim of the polyethylene cup

Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation.

Clinical scores were available for all patients and metal ion levels for MoM bearing patients.

Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups.

Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion.

Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours.

Cite this article: Bone Joint J 2015;97-B:1175–82.

I believe ceramic-on-polyethylene should be used in all patients undergoing THA. I believe the issues that one must look at include wear and osteolysis, bearing fracture and in 2018 corrosion/adverse local tissue reaction (ALTR). If one looks at these aspects it is clear ceramic-on-polyethylene is the bearing of choice. In the literature, there is a paucity of studies comparing metal-on-polyethylene with ceramic-on-polyethylene total hips. The data suggests no real difference in survivorship but less wear. However, most studies are not comparative studies and are underpowered to see these differences. The only data that is powered to see these differences is registry data. In first decade survivorship of metal-on- polyethylene is similar to ceramic-on-polyethylene. However, in the second decade the advantage is clearly with ceramic-on-polyethylene. However, in 2018, the major issue is corrosion and subsequent ALTR. While corrosion at the femoral head and stem taper has been seen for many years, in 2012 an article by Cooper et al. highlighted that this corrosion may lead to ALTR. They reported on 10 cases with variable presentation and no specific factor was found in their study or any study to date that will lead to corrosion and ALTR. More recently, a study from our center highlighted that dislocation may be the first presentation of ALTR. In this study, 10 cases of dislocation presented at an mean of 8 months with their first dislocation. Components were well positioned and it was concluded that the ALTR was the cause for the dislocation. Today any patient with new onset pain, stiffness or instability with a metal-on-polyethylene THA should be worked up for ALTR. The question of why this is happening now is important to answer. Numerous theories have been proposed, most likely it is a combination of these factors: change in trunnion dimension/surface, increasing head size, trunnion preparation and impaction force. It also appears to be stem dependent. In a study by McGrory et al. they found a 1% prevalence of ALTR in just over 1300 cases with one particular femoral stem. At present, however, we cannot predict at all which patient will develop ALTR and therefore we have gone to ceramic-on-polyethylene in all our THAs. In summary, the ideal bearing has low wear, low corrosion potential, generalizable, easy to revise, versatile, biocompatible and safe. In 2018, ceramic-on-polyethylene as a bearing fulfills all these criteria and should be the bearing of choice in total hip replacement

Objectives. Our study aimed to examine not only the incidence but also the impact of noise from two types of total hip replacement articulations: ceramic-on-ceramic and ceramic-on-polyethylene. . Methods . We performed a case-controlled study comparing subjective and objective questionnaire scores of patients receiving a ceramic-on-ceramic or a ceramic-on-polyethylene total hip replacement by a single surgeon. Results. There was a threefold higher incidence of noise from patients in the ceramic-on-ceramic group compared with the control group. The impact of this noise was significant for patients both subjectively and objectively. Conclusions. This study reports a high patient impact of noise from ceramic-on-ceramic total hip replacements. This has led to a change in practice by the principal author. Cite this article: Bone Joint Res 2014;3:183–6

Objectives. Few studies have assessed outcomes following non-metal-on-metal hip arthroplasty (non-MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD). We assessed outcomes following non-MoMHA revision surgery performed for ARMD, and identified predictors of re-revision. Methods. We performed a retrospective observational study using data from the National Joint Registry for England and Wales. All non-MoMHAs undergoing revision surgery for ARMD between 2008 and 2014 were included (185 hips in 185 patients). Outcome measures following ARMD revision were intra-operative complications, mortality and re-revision surgery. Predictors of re-revision were identified using Cox regression. Results. Intra-operative complications occurred in 6.0% (n = 11) of the 185 cases. The cumulative four-year patient survival rate was 98.2% (95% CI 92.9 to 99.5). Re-revision surgery was performed in 13.5% (n = 25) of hips at a mean time of 1.2 years (0.1 to 3.1 years) following ARMD revision. Infection (32%; n = 8), dislocation/subluxation (24%; n = 6), and aseptic loosening (24%; n = 6) were the most common re-revision indications. The cumulative four-year implant survival rate was 83.8% (95% CI 76.7 to 88.9). Multivariable analysis identified three predictors of re-revision: multiple revision indications (hazard ratio (HR) = 2.78; 95% CI 1.03 to 7.49; p = 0.043); selective component revisions (HR = 5.76; 95% CI 1.28 to 25.9; p = 0.022); and ceramic-on-polyethylene revision bearings (HR = 3.08; 95% CI 1.01 to 9.36; p = 0.047). Conclusions. Non-MoMHAs revised for ARMD have a high short-term risk of re-revision, with important predictors of future re-revision including selective component revision, multiple revision indications, and ceramic-on-polyethylene revision bearings. Our findings may help counsel patients about the risks of ARMD revision, and guide reconstructive decisions. Future studies attempting to validate the predictors identified should also assess the effects of implant design (metallurgy and modularity), given that this was an important study limitation potentially influencing the reported prognostic factors. Cite this article: G. S. Matharu, A. Judge, D. W. Murray, H. G. Pandit. Outcomes following revision surgery performed for adverse reactions to metal debris in non-metal-on-metal hip arthroplasty patients: Analysis of 185 revisions from the National Joint Registry for England and Wales. Bone Joint Res 2017;6:405–413. DOI: 10.1302/2046-3758.67.BJR-2017-0017.R2

Ceramic bearing fractures are rare events, but mandate revision and implantation of new bearings. Revisions using metal heads have been reported to lead to gross volumetric head wear (due to abrasive retained ceramic micro-debris), cobalt toxicity, multi-organ failure and death. Such complications are widely published (50+ reports), yet we know that patients continue to be put at risk. Using data from the NJR and AOANJRR, this study seeks to compare the risk of re-revision and death by revision bearing combination following a ceramic bearing fracture. Data were extracted from the NJR and AOANJRR, identifying revisions for ceramic bearing fracture. Subsequent outcomes of survival, re-revision and death were compared between revision bearing combinations (ceramic-on-ceramic, ceramic-on-polyethylene, and metal-on-polyethylene). 366 cases were available for analysis from the NJR dataset (MoP=34, CoP=112, CoC=221) and 174 from the AOANJRR dataset (MoP=17, CoP=44, CoC=113). The overall incidence rate of adverse outcome (revision or death) was 0.65 for metal heads and 0.23 for ceramic head articulations (p=0.0012) across the whole time period (NJR). Kaplan-Meir survival estimates demonstrate an increased risk of both re-revision and death where a metal head has been used vs a ceramic head following revision for ceramic fracture. There are few decisions in arthroplasty surgery that can lead to serious harm or death for our patients, but revision using a metal head following ceramic bearing fracture is one of them. This study enhances the signal of what is already known but previously only reported as inherently low-level evidence (case reports and small series) due to event rarity. Use of a metal head in revision for ceramic fracture represents an avoidable patient safety issue, which revision guidelines should seek to address

Background. Prosthetic implants used in primary total hip replacements have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal); head sizes (small <36mm, large 36mm+); and fixation techniques (cemented, uncemented, hybrid, reverse hybrid), which influence prosthesis survival, patient quality of life, and healthcare costs. This study compared the lifetime cost-effectiveness of implants to determine the optimal choice for patients of different age and gender profiles. Methods. In an economic decision Markov model, the probability that patients required one or more revision surgeries was estimated from analyses of UK and Swedish hip joint registries, for males and females aged <55, 55–64, 65–74, 75–84, and 85+ years. Implant and healthcare costs were estimated from hospital procurement prices, national tariffs, and the literature. Quality-adjusted life years were calculated using utility estimates, taken from Patient-Reported Outcome Measures data for hip procedures in the UK. Results. Optimal choices varied between traditionally used cemented metal-on-polyethylene and cemented ceramic-on-polyethylene implants. Small head cemented ceramic-on-polyethylene implants were optimal for males and females aged under 65. The optimal choice for adults aged 65 and older was small head cemented metal-on-polyethylene implants. Conclusions. The older the patient, the higher the probability that small head cemented metal-on-polyethylene implants are optimal. Small head cemented ceramic-on-polyethelyne implants are optimal for adults aged under 65. Our findings can influence NICE guidance, clinical practice, and commissioning of services. Funding. NIHR Research for Patient Benefit programme PB-PG-0613-31032

The objective of this study was to determine whether the bearing surface is a risk factor for revision after late dislocation in total hip arthroplasty (THA). Data from primary THAs were extracted from the New Zealand Joint Registry over a 13-year period. The mean age of patients was 68.9 years; 53.2% were female. The surgical approach used was posterior in 66% of THAs, lateral in 29% and anterior in 5%. There were 53,331 (65.1%) metal-on-polyethylene THAs, 14,093 (17.2%) ceramic-on-polyethylene, 8,177 (10.0%) ceramic-on-ceramic, 461 (0.5%) ceramic-on-metal, 5910, and (7.2%) metal-on-metal. The primary endpoint was late revision for dislocation, with ‘late’ defined as greater than one year post-operatively. 73,386 hips were available for analysis. The overall revision rate was 4.3% (3,130 THAs), 1.1% (836) were revised for dislocation. Only 0.65% (470) hips were revised for dislocation after the first post-operative year. The unadjusted hazard ratios (HR) showed significantly higher rates of revision for dislocation in ceramic-on-polyethylene (HR 2.48; p=0.001) and metal-on-polyethylene (HR 2.00; 95% p =0.007) compared to ceramic-on-ceramic. However, when adjusted for head size, age and surgical approach, only ceramic-on-polyethylene (HR 2.10; p=0.021) maintained a significantly higher rate of revision, whereas metal-on-polyethylene approached significance (HR 1.76; 95% p = 0.075). In New Zealand, dislocation is the most common reason for revision, ahead of aseptic loosening of the acetabular component. The relationships between bearing materials and risk of revision for late dislocation is controversial. However, in this study ceramic-on-ceramic shows lower risk rates for revision than other bearing surface combinations. Low wear and less debris, limited peri-articular inflammatory reaction and an healthy fibrotic pseudo-capsule are potential factors determining long-term stability of the hip joint

Total hip arthroplasty (THA) performed in patients aged 60 years and younger requires several decades of implant use under increased activity demands. Implant longevity and stable fixation are necessary for 30 or more years. The search for the optimal bearing combination for use in younger, high demand patients presents a challenge for orthopaedic surgeons as they consider the pros and cons of each material and interaction. A recent U.S. study of implant utilization trends that included 174 hospitals and 105,000 THA between 2001 and 2012 found that in 2012 93% of THA were cementless and 35% of THA bearings were ceramic-on-highly crosslinked polyethylene (HXLPE). Another recent article used the Nationwide Inpatient Sample from 2009 to 2012 to study bearing usage trends in 9265 primary THA in patients 30 years old or younger. The researchers observed ceramic-on-polyethylene as the most commonly bearing surface, used in 36% of patients, and which represented an increase from an earlier study of extremely young patients undergoing primary THA between 2006 to 2009, use of so-called hard-on-hard bearings decreased. Benefits of ceramic-on-HXLPE bearings are that unlike metal-on-polyethylene and metal-on-metal combinations, taperosis and adverse reactions to metal debris are non-existent. Ceramic-on-polyethylene is forgiving, it is an extremely low wear couple, it is the current presenter's bearing of choice in high demand patients, and it is a good option in the scenario of revision of failed metal-on-metal or for taperosis. Advantages to bulk ceramics are: extremely hard and scratch resistant to third body wear, not damaged by instruments and repositioning, excellent wettability, extreme low wear against itself with no known pathogenic reaction to ceramic particles, inherently stable with no oxidation or aging effect, no corrosion, safe in terms of metal ion release, no known risk of hypersensitivity or allergy, and no concerns about biological reaction. Biolox® (Ceramtec AG; Plochingen, Germany) ceramics have been available since 1974, with fourth generation Biolox® Delta introduced in 2003. Extensive clinical experience includes over 1630 published studies with over 12 million Biolox® components implanted with almost every available hip system. Two recent meta-analyses studies of randomised controlled trials comparing ceramic-on-ceramic to ceramic-on-polyethylene found significantly higher linear wear in ceramic-on-polyethylene but higher incidences of noise and fracture in ceramic-on-ceramic THA. There were no differences in revision, function, dislocation, osteolysis or loosening. A recent meta-analysis review of randomised controlled trials reporting survivorship of ceramic-on-ceramic, ceramic-on-HXLPE, and metal-on-HXLPE found no difference among bearing surfaces in risk of revision after primary THA in patients younger than 65. Risk ratio for revision was 0.65 (p=0.50) between ceramic-on-ceramic and ceramic-on-HXLPE, and 0.40 (p=0.34) between ceramic-on-ceramic and metal-on-HXLPE. A recent study of ceramic-on-HXLPE bearings for 130 cementless THA in 119 patients younger than 50 years at mean follow-up of 8.3 years (range, 7–9) reported a mean post-operative Harris hip score of 94, UCLA activity score of 8.1, no acetabular revisions, no osteolysis, no head or liner fracture, and 0.022 ± 0.003 mean annual penetration rate of the femoral head. While longer follow-up is necessary, ceramic-on-HXLPE bearings are an attractive option in younger, high demand patients undergoing primary THA

Aims. Second-generation metal-on-metal (MoM) articulations in total hip arthroplasty (THA) were introduced in order to reduce wear-related complications. The current study reports on the serum cobalt levels and the clinical outcome at a minimum of 20 years following THA with a MoM (Metasul) or a ceramic-on-polyethylene (CoP) bearing. Methods. The present study provides an update of a previously published prospective randomized controlled study, evaluating the serum cobalt levels of a consecutive cohort of 100 patients following THA with a MoM or a CoP articulation. A total of 31 patients were available for clinical and radiological follow-up examination. After exclusion of 11 patients because of other cobalt-containing implants, 20 patients (MoM (n = 11); CoP (n = 9)) with a mean age of 69 years (42 to 97) were analyzed. Serum cobalt levels were compared to serum cobalt levels five years out of surgery. Results. The median cobalt concentration in the MoM group was 1.04 μg/l (interquartile range (IQR) 0.64 to 1.70) at a mean of 21 years (20 to 24) postoperatively and these values were similar (p = 0.799) to cobalt levels at five years. In the CoP control group, the median cobalt levels were below the detection limit (< 0.3 μg/l; median 0.15 μg/l, IQR 0.15 to 0.75) at 20 years. The mean Harris Hip Score was 91.4 points (61 to 100) in the MoM group and 92.8 points (63 to 100) in the CoP group. Conclusion. This study represents the longest follow-up series evaluating the serum cobalt levels after 28 mm head MoM bearing THA and shows that serum cobalt concentrations remain at low levels at a mean of 21 years (20 to 24) after implantation. Cite this article:Bone Joint Res. 2020;9(3):145–150

Background. An increased incidence of periprosthetic osteolysis, resulting in loss of biologic fixation, has been recently reported in contemporary THAs with low-carbide metal-on-metal compared to metal-on-polyethylene couple bearings. A hypersensitivity reaction due to Co and Cr debris is reported as a potential cause for failure of THAs with high-carbide bearings, but there are no evidence-based data for this reaction in low-carbide metal-on-metal bearings. Questions/purposes. We investigated whether there were differences in immunologic hypersensitivity reactions in retrievals from revised THAs with COP versus MOM bearing couples. Patients and Methods. We compared newly formed capsule and periprosthetic interface membranes retrieved from revision surgery due to aseptic failure in 20 patients with low-carbide bearings and 13 patients with ceramic-on-polyethylene bearings. For control tissue we obtained samples from the hip capsule during the primary THA implantation in 13 patients with low-carbide bearings and seven with ceramic-on-polyethylene. We examined the tissues with conventional histologic and immunohistochemical methods. Results. Compared to the controls and the tissue from patients with ceramic-on-polyethylene bearings, the tissues from patients with low-carbide metal-on-metal bearings were associated with (1) extensive necrosis and fibrin exudation in the newly formed hip capsule and (2) diffuse and perivascular lymphocytic infiltration of a higher degree than in the ceramic-on-polyethylene hips in conventional histologic examination and (3) more T than B cells. Conclusions. The conventional histologic and immunohistochemical findings in tissues retrieved from failed THAs with low-carbide metal-on-metal bearings are consistent with a link between hypersensitivity and osteolysis with low-carbide bearing couple THA

Introduction. We investigated predictors of poor outcomes following metal-on-metal hip arthroplasty (MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD), to help inform the revision threshold and type of reconstruction. Patients and Methods. A retrospective cohort study was performed involving 346 MoMHAs revised for histologically confirmed ARMD at two specialist centres (245=hip resurfacing, 101=total hip arthroplasty). Numerous preoperative (blood metal ions and imaging) and intraoperative (findings, and components removed/implanted) factors were used to predict poor outcomes. Poor outcomes were postoperative complications (including re-revisions), 90-day mortality, and poor Oxford Hip Scores (<27/48). Multivariable logistic regression models for predicting poor outcomes were developed using stepwise selection methods. Results. Cumulative implant survival rate seven-years after ARMD revision was 87.0% (95% CI=81.0%-91.2%). Poor outcomes occurred in 39% (n=135). Shorter time (under four-years) from primary to revision surgery (odds ratio (OR)=2.12, CI=1.00–4.46) was the only preoperative predictor of poor outcomes. Pre-revision metal ions and imaging did not influence outcomes. Single-component revisions increased the risk of poor outcomes (acetabular or femoral vs. all component revisions; OR=2.99, CI=1.50–5.97). Intraoperative factors reducing the risk of poor outcomes included the posterior approach (OR=0.22, CI=0.10–0.49), revision head sizes ≥36mm (vs. <36mm: OR=0.37, CI=0.18–0.77), ceramic-on-polyethylene (OR vs. ceramic-on-ceramic=0.30, CI=0.14–0.66) and metal-on-polyethylene revision bearings (OR vs. ceramic-on-ceramic=0.37, CI=0.17–0.83). Discussion. This large cohort study demonstrated 39% of patients experience poor outcomes following MoMHA revision for ARMD. This information will help surgeons when counselling patient's pre-revision about the expected prognosis. No threshold exists for recommending ARMD revision, therefore surgeons must make decisions on an individual case basis. However, surgeons can make intraoperative decisions that influence outcomes following ARMD revision. Conclusion. We recommend optimal outcomes following ARMD revision may be achieved if surgeons use the posterior approach, revise all MoMHA components, and use ≥36mm ceramic-on-polyethylene or metal-on-polyethylene articulations

Aims. The aim of this study was to describe temporal trends and survivorship of total hip arthroplasty (THA) in very young patients, aged ≤ 20 years. Patients and Methods. A descriptive observational study was undertaken using data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man between April 2003 and March 2017. All patients aged ≤ 20 years at the time of THA were included and the primary outcome was revision surgery. Descriptive statistics were used to summarize the data and Kaplan–Meier estimates calculated for the cumulative implant survival. Results. A total of 769 THAs were performed in 703 patients. The median follow-up was 5.1 years (interquartile range (IQR) 2.6 to 7.8). Eight patients died and 35 THAs were revised. The use of metal-on-metal (MoM) bearings and resurfacing procedures declined after 2008. The most frequently recorded indications for revision were loosening (20%) and infection (20%), although the absolute risk of these events occurring was low (0.9%). Factors associated with lower implant survival were MoM and metal-on-polyethylene (MoP) bearings and resurfacing arthroplasty (vs ceramic-on-polyethylene (CoP) and ceramic-on-ceramic (CoC) bearings, p = 0.002), and operations performed by surgeons who undertook few THAs in this age group as recorded in the NJR (vs those with five or more recorded operations, p = 0.030). Kaplan–Meier estimates showed 96% (95% confidence interval (CI) 94% to 98%) survivorship of implants at five years. Conclusion. Within the NJR, the overall survival for very young patients undergoing THA exceeded 96% during the first five postoperative years. In the absence of studies that can better account for differences in the characteristics of the patients, surgeons should consider the association between early revision and the type of implant, the number of THAs performed in these patients, and the bearing surface when performing THA in very young patients. Cite this article: Bone Joint J 2018;100-B:1320–9