Introduction. The National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man (NJR) monitors the performance of primary total hip arthroplasty (THA) implants and summarizes usage and outcomes for specific hip systems. The objectives of this study were to 1) determine if survivorship for the PROCOTYL® L acetabular cup, a hemispherical press-fit cup coated with hydroxyapatite and a metal on XLPE articulation, is significantly different from all other cementless cups in the NJR and 2) to analyze patient reported outcomes measures (PROMs) at a minimum five year follow-up for the subject cup. Methods. The database of the NJR was searched for demographic information and survivorship data for all THAs performed with the PROCOTYL® L cup (metal on XLPE) and all other cementless cups. Survivorship data for both groups was adjusted to exclude metal on metal bearings and compared for all revisions and acetabular revisions only. The Cox Proportional Hazards model for the revision risk ratio of the subject cup to all cementless cups was also calculated. Patients with the subject cup implanted for at least five years were mailed a PROMs program questionnaire consisting of the Oxford Hip, EQ-5D, and EQ VAS scores. No pre-operative PROMs scores were collected. Results. Patient demographic information for the subject system and all cementless cups is provided in Figure 1. As seen in Figure 2, the six-year survivorship for the 1,172 THAs using the subject system (97.8%) was slightly higher than the survivorship for all cementless cups (97.5%), but the difference was not statistically significant (Figure 3). The 1, 2, and 5 year survivorship for the subject cup also exceeded the survivorship of all cementless cups, but without statistically significant differences. When just the cup was revised, the subject system survivorship was similar to survivorship for all cementless cups for years 1 through 6 (Figure 2). Patients with the subject system implanted for an average of 5.73 – 5.75 years reported average Oxford Hip, EQ-5D, and EQ VAS Scores of 39.13 ± 9.93, 0.775 ± 0.273, and 75.87 ± 17.71, respectively. Conclusions. The subject acetabular cup was associated with survivorship similar to that of other cementless acetabular cups. Patients implanted with the subject system for at least five years reported what are considered satisfactory Oxford Hip, EQ5D, and EQVAS score outcomes. These results represent the first report of midterm outcomes with the subject system. For figures/tables, please contact authors directly.

Computer navigation has the potential to revolutionise orthopaedic surgery, although according to the latest 7. th. Annual NJR Report, only 2% of the 5 800 unicompartmental knee replacements (UKRs) performed in 2009 were carried out using ‘image guidance.’ The report also states an average 3-year revision rate for UKRs of 6.5%. Previous NJR data has shown that this figure rises up to 12% for certain types of prosthesis. We suspect that a significant proportion of these revisions are due to failure secondary to component malpositioning. We therefore propose that the use of computer navigation enables a more accurate prosthesis placement, leading to a reduction in the revision rate for early failure secondary to component malpositioning. Our early results of one hundred consecutive computer navigated UKRs are presented and discussed. Ninety-two patients having had one hundred consecutive computer navigated UKRs were reviewed both clinically and radiographically. The Smith & Nephew Accuris fixed-bearing modular prosthesis was used in all cases, with the ‘Brainlab’ navigation system. Pre-operative aim was neutral tibial cut with three degrees posterior slope. Post-operative component alignment was measured with PACs web measuring tools. Patients were scored clinically using the Oxford Knee Score. Our patient cohort includes 54 male knees and 46 female knees. Average age is 66.6yrs. Average length of stay was 3.7 days, (range 2–7.) With respect to the tibial component, average alignment was 0.7° varus, and 2.32° posterior slope. All components were within the acceptable 3 degrees deviation. Functional scores are very satisfactory, with an overall patient satisfaction rate of 97%. To date, only one UKR has required revision. This was due to ongoing medial pain due to medial overhang, not related to computer navigation. There was one superficial infection, with full resolution following a superficial surgical washout, debridement and antibiotics. Unlike complications reported in the NJR, we report no peri-prosthetic fractures or patella tendon injuries. Our results demonstrate accurate prosthesis placement with the use of computer navigation. Furthermore, clinical scores are highly satisfactory. Our current revision rate is 1% at a mean of 27 months post-op. Although longer-term follow-up of our group is required, our results compare very favourably to statistics published in the NJR, (average 3-year revision rate 6.5%.) The only major differences appear to be the type of prosthesis used and the use of computer navigation. It is our proposal that computer navigation reduces the number of revisions required due to component malpositioning and subsequent failure. Furthermore, we believe that this challenging surgery is made easier with the use of computer navigation. We expect our longer-term results to show significant benefits of computer navigation over conventional techniques

Aims. Our primary aim was to establish the proportion of female orthopaedic consultants who perform arthroplasty via cases submitted to the National Joint Registry (NJR), which covers England, Wales, Northern Ireland, the Isle of Man, and Guernsey. Secondary aims included comparing time since specialist registration, private practice participation, and number of hospitals worked in between male and female surgeons. Methods. Publicly available data from the NJR was extracted on the types of arthroplasty performed by each surgeon, and the number of procedures of each type undertaken. Each surgeon was cross-referenced with the General Medical Council (GMC) website, using GMC number to extract surgeon demographic data. These included sex, region of practice, and dates of full and specialist registration. Results. Of 2,895 surgeons contributing to the NJR in 2023, 102 (4%) were female. The highest proportions of female surgeons were among those who performed elbow (n = 25; 5%), shoulder (n = 24; 4%), and ankle (n = 8; 4%) arthroplasty. Hip (n = 66; 3%) and knee arthroplasty (n = 39; 2%) had the lowest female representation. Female surgeons had been practising for a median of 10.4 years since specialist registration compared to 13.7 years for males (p < 0.001). Northern Ireland was the region with the highest proportion of female arthroplasty surgeons (8%). A greater proportion of male surgeons worked in private practice (63% vs 24%; p < 0.001) and in multiple hospitals (74% vs 40%; p < 0.001). Conclusion. Only 4% of surgeons currently contributing cases to the NJR are female, with the highest proportion performing elbow arthroplasty (5%). Female orthopaedic surgeons in the NJR are earlier in their careers than male surgeons, and are less involved in private practice. There is a wide geographical variation in the proportion of female arthroplasty surgeons. Cite this article: Bone Jt Open 2024;5(8):637–643

Abstract. Background and study aim. The UK National Joint Registry(NJR) has not reported total knee replacement (TKR)survivorship based on design philosophy alone, unlike its international counterparts. We report outcomes of implant survivorship based on design philosophy using data from NJR's 2020 annual report. Materials and methods. All TKR implants with an identifiable design philosophy from NJR data were included. Cumulative revision data for cruciate-retaining(CR), posterior stabilised(PS), mobile-bearing(MB) design philosophies was derived from merged NJR data. Cumulative revision data for individual brands of implants with the medial pivot(MP) philosophy were used to calculate overall survivorship for this design philosophy. The all-cause revision was used as the endpoint and calculated to 15 years follow-up with Kaplan-Meier curves. Results. 1,144,384 TKRs were included. CR is the most popular design philosophy (67.4%), followed by PS (23.1%), MB (6.9%) and least commonly MP (2.6%). MP and CR implants showed the best survivorship (95.7% and 95.6% respectively) at 15 years which is statistically significant at, and beyond, 10 years. Observed survivorship was lower at all time points with the PS and MB implants (94.5% for both designs at 15 years). Conclusions. While all design philosophies considered in this study survive well, CR and MP designs offer statistically superior survivorship at and beyond 10 years. MP design performs better than CR beyond 13 years yet, remain the least popular design philosophy used. Publishing data based on knee arthroplasty design philosophy would help surgeons when making decisions on implant choice

Aims. The primary aim is to estimate the current and potential number of patients on NHS England orthopaedic elective waiting lists by November 2020. The secondary aims are to model recovery strategies; review the deficit of hip and knee arthroplasty from National Joint Registry (NJR) data; and assess the cost of returning to pre-COVID-19 waiting list numbers. Methods. A model of referral, waiting list, and eventual surgery was created and calibrated using historical data from NHS England (April 2017 to March 2020) and was used to investigate the possible consequences of unmet demand resulting from fewer patients entering the treatment pathway and recovery strategies. NJR data were used to estimate the deficit of hip and knee arthroplasty by August 2020 and NHS tariff costs were used to calculate the financial burden. Results. By November 2020, the elective waiting list in England is predicted to be between 885,286 and 1,028,733. If reduced hospital capacity is factored into the model, returning to full capacity by November, the waiting list could be as large as 1.4 million. With a 30% increase in productivity, it would take 20 months if there was no hidden burden of unreferred patients, and 48 months if there was a hidden burden, to return to pre-COVID-19 waiting list numbers. By August 2020, the estimated deficits of hip and knee arthroplasties from NJR data were 18,298 (44.8%) and 16,567 (38.6%), respectively, compared to the same time period in 2019. The cost to clear this black log would be £198,811,335. Conclusion. There will be up to 1.4 million patients on elective orthopaedic waiting lists in England by November 2020, approximate three-times the pre-COVID-19 average. There are various strategies for recovery to return to pre-COVID-19 waiting list numbers reliant on increasing capacity, but these have substantial cost implications. Cite this article: Bone Jt Open 2021;2(2):103–110

The National Joint Registry (NJR) was set up by the Department of Health to collect information on all joint replacements. The NJR data is externally validated against nationally collated Hospital Episode Statistics (HES). Errors associated with the use of HES data have been widely documented. We sought to explore the accuracy of the NJR data, for a single surgeon, against a prospectively collected personal logbook. The NJR and logbook were compared over a 3-year period (01/07/2009 to 30/06/2012). Total procedure recorded in the personal logbook was 684 and in the NJR was 681. TKR in personal log book was 304 and in NJR 316, revision knee's in personal logbook 45 and in NJR 36, THR 274 in personal logbook and 271 in NJR, revision hip procedures in personal logbook 64 and 58 in NJR. Whilst the total number of procedures captured correlates closely (681 vs 684) there is more variation with the different individual procedures. This may be due to the addition of 11% of HES data used for this time period by the NJR as it is known to be inaccurate. This therefore demonstrates the importance of maintaining your own accurate records

Mortality following hip arthroplasty is affected by a large number of confounding variables each of which must be considered to enable valid interpretation. The aim of this study was to establish whether it is possible to determine a true cause-and-effect relationship between the risk of mortality and data that are routinely collected by the NJR and to establish the degree to which variation in the mortality rate could be explained by each variable. Relevant variables available from the 2011 NJR data setwere included in a Cox model. We carried out two analyses:. Firstly, we conducted an analysis of data collected from the NJR data set used in preparation of the NJR's 8th Annual Report (2011) looking for an association between the variables collected and the risk of mortality. Secondly, as social deprivation is also known to influence mortalityrates but is not routinely collected as part of the NJR data set, a further analysis was performed which included social deprivation data derived from partial postcodes. Mortality rates in hip arthroplasty patients were lower than in the age matched population across all hip types. Age at surgery, ASA grade, diagnosis, gender, provider type, hip type and lead surgeon grade all had a significant effect on mortality. Schemper's statistic showed that only 18.98% of the variation in mortality was explained by the variables available in the NJR data set. It is inappropriate to use Registry data to study an outcome affected by a multitude of confounding variables when these cannot be adequately accounted for in the available data set

Dual mobility (DM) is an established bearing option in Total Hip Arthroplasty (THA). The traditional mono-block DM designs have limited ability for additional fixation, whereas the modular DM designs allow additional screw fixation but limit internal diameter and have the potential to generate metal debris. We report the early results of a CoCrMo alloy mono-block implant manufactured by additive technology with a highly porous ingrowth surface to enhance primary fixation and osseointegration. Prospective follow-up of the Duplex. TM. implant first inserted in March 2016 enrolled into Beyond Compliance (BC). Primary outcome measure was all-cause revision and secondary outcomes dislocation, peri-prosthetic fracture (PPF) and Oxford Hip Score (OHS). Patients were risk stratified and all considered to be high risk for instability. Complications were identified via hospital records, clinical coding linkage using national database and via BC website. 159 implants in 154 patients with a mean age 74.0 years and a maximum F/U of 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 cemented Polished taper stem (PTS) had a Type B PPF rate of 2.1% requiring revision/fixation. Compared to conventional THA 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%). Every patient had at least one risk factor for falling and >50% of cohort had 4 or more risk factors using NICE tool. We believe our results demonstrate that risk stratification successfully aids implant selection to prevent dislocation in high-risk patients. This novel design has provided excellent early results in a challenging cohort where individuals are very different to the “average” THA patient. NJR data on DM has reported an increase in revision for PPF. A “perfect storm” maybe created using DM in high-risk falls risk population. This re-enforces the need to consider all patient and implant factors when deciding bearing selection

Objectives. Total hip replacement is increasingly being conducted in younger and more active patients, so surgeons often use bearing surfaces with improved wear characteristics, such as ceramic on ceramic. The primary objective of this study was to determine if survivorship for a BIOLOX® delta ceramic on delta ceramic couple used with the PROCOTYL® L acetabular cup is significantly different from all other cementless cups in a large arthroplasty registry. The secondary objective of this study was to analyze patient reported outcomes measures (PROMs) of the subject cup with a minimum five year follow-up. Methods. Patient demographics and survivorship data was collected from the National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man (NJR) database for all total hip replacements performed with the PROCOTYL® L cup used in combination with a delta-on-delta articulation, as well as for all other cementless cups. Survivorship data was compared for all revisions and cup revisions only and data was adjusted to exclude metal on metal articulations. The hazard ratio of the subject system to all cementless cups was also calculated with the Cox Proportional Hazards model. Patients with the subject components implanted for a minimum of five years completed Oxford Hip, EQ-5D, and EQ VAS score questionnaires. Results. The patient demographic data collected for the subject components and all cementless cups is provided in Figure 1. Six-year survivorship for the subject cup (98.6%) was similar to survivorship for all cementless cup revisions in the NJR database (98.5%), as seen in Figure 2. When the cup alone was revised, six-year survivorship of the subject cup (98.6%) and all NJR cementless cups (98.5%) was also similar. However, the subject cup survivorship remained at 98.6% from 4 to 6 years post-implantation, while survivorship for all cementless cups decreased slightly from years 4 to 6. The similarities between the revision risk of the subject system and all cementless cups in the NJR can be seen in the Cox Proportional Hazards model for revision risk ratios provided in Figure 3. Patients with the subject cup implanted for an average of 5.88 years reported Oxford Hip, EQ-5D, and EQ VAS scores of 39.60 ± 10.78, 0.801 ± 0.259, and 75.49 ± 19.25, respectively. Conclusions. The subject acetabular cup with a ceramic on ceramic articulation exhibited similar survivorship to all other cementless acetabular cups, excluding those with metal on metal bearings, in the NJR. Patients implanted with the subject system for an average of 5.88 years reported what are considered satisfactory Oxford Hip, EQ-5D, and EQ VAS scores. This survivorship and PROMs data is the first report of mid-term outcomes with the subject components

This study utilised NJR primary hip data from the 6. th. Annual Report to determine the rate and indication for revision between cemented, uncemented, hybrid and resurfacing prosthetic groups. Regression analysis was performed to identify the influence of gender and ASA grade on these revision rates. Validity of the data was interrogated by exploring for episodes of misclassification. Results. We identified 2,264 misclassified episodes within the four groups (Misclassification rate 2.7% primary, 4.3% revision procedures). Analysis was performed using the “reclassified dataset”. The Kaplan-Meier revision rates at 3 years were 0.9% (95%CI: 0.8%-1.0%) for cemented prostheses, 1.9% (95%CI: 1.8%-2.0%) for uncemented hips, 1.2% (95%CI: 1.0%-1.4%) for hybrids and 3.0%, (95%CI: 2.7%-3.3%) in the resurfacing group. The trends in revision rates were comparable to those published in the NJR (6. th. Ed. n. ) with significant differences across all groups (p< 0.0001). Revision rates in the under 55 year age group showed an identical hierarchy with cemented and hybrid arthroplasty having the lowest revision rates. Cox Regression analysis indicated that both the prosthesis group in isolation and the interaction between prosthesis group and ASA grade significantly influenced the rate of failure (p< 0.001). Indications for revision showed significant differences in rates for, pain, aseptic loosening, dislocation and malalignment between prosthesis types (p< 0.001). The indications including Aseptic loosening, pain, malalignment and dislocation all demonstrated similar trends in revision rates between prosthetic groups with cemented hips having the lowest rates followed by ascending rates for hybrid, uncemented and resurfacing groups. The exception being dislocation with resurfacings having the lowest revision rates. Discussion. This study provides important baseline revision rates by indication for each prosthetic group from which future comparisons can be made. Areas of misclassification within the NJR dataset have been reported back for future annual analysis

Loosening is generally the most common reason for revision TKA. In the AOA NJR, the rate of revision varies depending on fixation. Cemented fixation has a lower rate of revision than cementless fixation; 6.7% vs. 8.2% at 14 years. Loosening does occur more frequently in younger patients and in males. Tibial component loosening is the most common. There is an opportunity for improvement. More durable fixation can be achieved through improved cement technique, rather than going cementless. De-bonding of the tibial baseplate from the cement is the mechanism of failure in up to 2.9% of total knee arthroplasties. Among seven surgeons at one center, there was a 6.4 fold range (0.7%-4.5%) in the occurrence of such loosening with the same prosthesis. This surgeon-related variability in tibial component de-bonding indicates that surgical technique influences loosening. In a laboratory study, earlier application of cement to metal increases bond strength (p<0.01) while later application reduces bond strength (p<0.05). Fat contamination of the tibial tray-cement interface reduces bond strength, but application of cement to the underside of the tibial tray prior to insertion substantially mitigates this (p<0.05)

Loosening is generally the most common reason for revision TKA. In the AOA NJR, the rate of revision varies depending on fixation. Cemented fixation has a lower rate of revision than cementless fixation; 6.7% vs. 8.2% at 14 years. Loosening does occur more frequently in younger patients and in males. Tibial component loosening is the most common. There is an opportunity for improvement. More durable fixation can be achieved through improved cement technique. De-bonding of the tibial baseplate from the cement is the mechanism of failure in up to 2.9% of total knee prostheses. Among seven surgeons at one center, there was a 6.4-fold range (0.7%-4.5%) in the occurrence of such loosening with the same prosthesis. This surgeon-related variability in tibial component de-bonding suggests that surgical technique influences loosening rates. In a laboratory study, earlier application of cement to metal increases bond strength (p<0.01) while later application reduces bond strength (p<0.05). Fat contamination of the tibial tray-cement interface reduces bond strength, but application of cement to the underside of the tibial tray prior to insertion substantially mitigates this (p<0.05)

Unicompartmental knee replacement (UKR) is associated with higher revision rates than total knee replacement and it has been suggested that surgeons should receive specific training for this prosthesis. We investigated the outcome of all UKR in a district general hospital over ten years. All patients who had received UKR from 2003 to 2013 were identified from theatre records, as were all revision knee arthroplasties. We contacted all patients (or their GP) with no known revision to ascertain UKR status. A life table analysis was used for three categories: all surgeons and types of UKR, Oxford UKR only and Oxford UKR by surgeons with specific training. There were 319 UKR (one loss to follow up), four types of prosthesis, 21 failures and a 5-year cumulative survival rate of 91.54%. There were 310 Oxford UKR with 17 failures and 5-year survival 93.56%. Surgeons with training in use of Oxford UKR completed 242 replacements with 10 failures and 5-year survival of 95.68%. In comparison with results for Oxford UKR in 11th annual NJR report, our results are satisfactory and support continued use of this prosthesis in a non-specialist centre. Our established programme of surveillance will monitor the survival of UKR in our hospital

A key theme of the GIRFT project is centralisation of complex orthopaedic procedures to “Specialist Units” and minimum surgeon volumes. We aimed to estimate the effects of implementing minimum unit and surgeon specific volumes upon orthopaedic units within the Severn region. Practice profiles for surgeons and units were generated using the NJR Surgeon and Hospital Profile Database. Minimum volume thresholds were set at 13 procedures/year for surgeons and 30 procedures/year for units. Median surgeon volumes were 33 (range 2–180) for primary TKR, 10 (range 2 – 64) for UKR, 2 (range 2 – 41) for PFJR and 5 (range 2–57) for Revision TKR. Amongst 48 surgeons performing UKR, 26 (54%) performed less than 13 procedures per year accounting for 108 (14%) procedures. Amongst 20 surgeons performing PFJR, 19 (95%) performed <13/year, accounting for 56 (58%) of cases. 49 Surgeons performed revision TKR with 24 (49%) performing <13 revisions per annum, accounting 151 (36%) procedures. Amongst 16 units performing UKR, 8 (50%) performed <30/year, accounting for 16% overall. Revision TKR was performed in 15 units whilst 8 (53%) performed <30/year, accounting for 62 (15%) cases. We invite discussion of the ramifications of minimum surgeon and unit volumes for Orthopaedic services in the Severn Region

The use of fourth generation ceramic as an orthopaedic biomaterial has proved to be a very efficient and has gained popularity for primary hip surgery in the last 8–10 years. Cumulative percentage probability of revision after 7 years for un-cemented CoC is 3.09% and for hybrid CoC is 2.00%, this compares favourably with traditional metal-on-UHMWPE un-cemented at 3.05% and hybrid at 2.35% (12th Annual Report - NJR, 2015). Such ceramic-on-ceramic hip prostheses are being implanted in ever younger, more active patients, and yet very few long-term large cohort retrieval studies are yet to be carried out due to the survivorship of the implants. It has been seen in previous studies that levels of wear in ceramic-on-ceramic bearing surface can be of the order of 0.2 mm. 3. /million cycles (Al-Hajjar, Fisher, Tipper, Williams, & Jennings, 2013). This is incredibly low when compared to studies that characterize wear in other bearing surface combinations. It has also been reported that an unusual stripe pattern of wear can occur in some in-vivo retrieved cups (Macdonald & Bankes, 2014) and it has further been postulated that this is caused by cup edge loading (Walter, Insley, Walter, & Tuke, 2004). The combined measurement challenge of stripe wear occurring at the edge of a low-wear ceramic-on-ceramic device is considerable, a solution to which is presented here. Current literature on wear measurement of such cases has been confined to in-vitro simulator studies and use of gravimetric measurement which by definition has limitations due to the lack of spacial characterisation. This paper details a novel method for measuring edge-wear in CoC acetabular liners. The method has been employed in an in-vitro study where it has been benchmarked against gravimetric measurements. These liners were measured on a CMM to determine the volume of material loss. The measurements were conducted as a blinded post-wear study akin to measurement of retrieved components. The most challenging part of this novel method was to create a reference geometry that replicates the free form edge surface of the ‘unworn’ cup using the residual post-wear surface. This was especially challenging due to the uncontrolled geometry at the cup edge and intersection of geometric features at this point. To achieve this, the geometry surrounding the wear patch was used to create a localized reference feature that minimised the effect of global form errors caused by hand polishing in the edge area. Furthermore, the reference geometry is compared with the measured surface to determine the linear penetration and volumetric wear loss. Result of this novel method can be seen in Fig 1. The findings have been compared to gravimetric results and a bar graph comparing two results can be seen in Fig 2. Overall the accuracy of the method for this cohort was 0.03–0.2 mm. 3. when compared to gravimetric reference measurements. This compares very favourably with previously published wear measurement methods and gives confidence in the ability to measure such small measurement volumes over complex geometry

For medial compartment disease UKR has many advantages over TKR. They give better function, faster recovery, lower morbidity and mortality but have a higher revision rate. Matched studies from the England and Wales National Joint Registry showed they are 60% more likely to achieve excellent outcomes (OKS>41) and 30% more likely to have excellent satisfaction. UKR patients were discharged 1.4 days earlier, had 35% less readmissions and 50% less major complications such as DVT/PE, infection, CVA and MI. The death rate was significantly lower: The hazard ratios being 0.2x at 30 days, 0.5x at 90 days and 0.85x at 8 years. However at 8 years the revision rate was 2x higher and the reoperation rate was 1.4x. If 100 patients receiving TKR had UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years. If patients were aware of this most would select a UKR. The main reason why UKR have a high revision rate in registries is that most surgeons do small numbers and restrict their use to patients with very early disease, who often do badly. In the NJR 8% of knees are UKR and surgeons do on average 5 per year. Surgeons doing more than 20% of knees as UKR have a much lower re-operation rate which is similar to that of TKR. The Mobile bearing UKR can safely be used in up to 50% allowing many patients to have the advantages of UKR and a low re-operation rate

Introduction:. Infection as an indication for revision has increased to 12% of the total revisions (UK NJR 9. th. report). However, it is next to impossible to find out the cause for a delayed prosthetic infection. With increasing number of arthroplasty procedures, is there a need for prophylactic antibiotics in patients with prostheses?. Methods:. At London Knee Meeting 2012, a total of 163 surgeons were asked to take part in a survey. This was to find out if they knew of any existing guidelines for prophylaxis for dental procedures, if there was a need to practice more uniformly, and if they recommend such prophylaxis to their patients routinely. The grade of the surgeon and their experience in years was also noted. Results:. Among the 163 surgeons who participated, 102 (62.6%) were arthroplasty surgeons. Of these, 73 (71.5%) were consultants with 3 or more years of experience. For this study, responses from these 102 surgeons were taken into consideration. Out of the 102 surgeons, only 39 (38%) were aware of AAOS recommendations. However, only 26 (25.5%) felt the need for such prophylaxis, other 37 (36%) were not sure if such prophylaxis was necessary. The remaining 39 (38.5%) did not think the prophylaxis was necessary. There was no difference found in the responses between the consultant and non-consultant surgeons. Conclusions:. From this survey, it is clear that there is no uniformity of the knowledge of existing recommendations for prophylaxis of such patients with prostheses. There is probably a need to develop robust guidelines for prophylaxis, given the devastating nature of an infected prosthesis

Introduction. Survival rates of recent total ankle replacement (TAR) designs are lower than those of other arthroplasty prostheses. Loosening is the primary indication for TAR revisions [NJR, 2014], leading to a complex arthrodesis often involving both the talocrural and subtalar joints. Loosening is often attributed to early implant micromotion, which impedes osseointegration at the bone-implant interface, thereby hampering fixation [Soballe, 1993]. Micromotion of TAR prostheses has been assessed to evaluate the stability of the bone-implant interface by means of biomechanical testing [McInnes et al., 2014]. The aim of this study was to utilise computational modelling to complement the existing data by providing a detailed model of micromotion at the bone-implant interface for a range of popular implant designs, and investigate the effects of implant misalignment during surgery. Methods. The geometry of the tibial and talar components of three TAR designs widely used in Europe (BOX®, Mobility® and SALTO®; NJR, 2014) was reverse-engineered, and models of the tibia and talus were generated from CT data. Virtual implantations were performed and verified by a surgeon specialised in ankle surgery. In addition to the aligned case, misalignment was simulated by positioning the talar components in 5° of dorsi- or plantar-flexion, and the tibial components in ± 5° and 10° varus/valgus and 5° and 10° dorsiflexion; tibial dorsiflexed misalignement was combined with 5° posterior gap to simulate this misalignment case. Finite element models were then developed to explore bone-implant micromotion and loads occurring in the bone in the implant vicinity. Results. Micromotion and bone loads peaked at the end of the stance phase for both the tibial and talar components. The aligned BOX and SALTO demonstrated lower tibial micromotion (with under 30% of bone-implant interface area subjected to micromotion larger than 100µm, as opposed to > 55% for Mobility; Figure 1). Talar micromotion was considerably lower for all designs, and no aligned talar component demonstrated micromotion larger than 100µm. The aligned SALTO showed the largest talar micromotion (Figure 2). Dorsiflexed implantation of all tibial components increased micromotion and bone strains compared to the reference case; interestingly, the SALTO tibial component, which demonstrated the lowest micromotion for the aligned case, also demonstrated the smallest changes in micromotion due to malpositioning (Figure 3). The posterior gap between the tibia and implant further increased bone strains. Dorsi- or plantar-flexed implantation of all talar components considerably increased micromotion and bone loads compared to the reference case (Figure 2), often resulting in micromotion exceeding 100µm. The SALTO talar component demonstrated the smallest changes in micromotion due to malpositioning. Discussion. The aligned Mobility had greater tibial micromotion than the SALTO and BOX, which agrees with higher revision rates reported in registry data (e.g. NZJR, 2014). The increased micromotion associated with dorsi- or plantar-flexion misalignment highlights the importance of aligning the implant correctly, and implies that SALTO can be more “forgiving” for malpositioning than the other TAR designs. Implant design and alignment are therefore important factors that affect the implant fixation and performance of the reconstructed ankle

Background and aim. Since the market withdrawal of the ASR hip resurfacing in August 2010 because of a higher than expected revision rate as reported in the Australian Joint Replacement Registry (AOAJRR), metal-on-metal hip resurfacing arthroplasty (MoMHRA) has become a controversial procedure for hip replacement. Failures related to destructive adverse local tissue reactions to metal wear debris have further discredited MoMHRA. Longer term series from experienced resurfacing specialists however, demonstrated good outcomes with excellent 10-to-15-year survivorship in young and active men. These results have recently been confirmed for some MoMHRA designs in the AOAJRR. Besides, all hip replacement registries report significantly worse survivorship of total hip arthroplasty (THA) in patients under 50 compared to older ages. The aim of this study was to review MoMHRA survivorship from the national registries reporting on hip resurfacing and determine the risk factors for revision in the different registries. Methods. The latest annual reports from the AOAJRR, the National Joint Registry of England and Wales (NJR), the Swedish Hip Registry (SHR), the Finnish Arthroplasty Registry, the New Zealand Joint Registry and the Arthroplasty Registry of the Emilia-Romagna Region in Italy (RIPO) were reviewed for 10-year survivorship of MoMHRA in general and specific designs in particular. Other registries did not have enough hip resurfacing data or long term data yet. The survivorship data were compared to conventional THA in comparable age groups and determinants for success/failure such as gender, age, diagnosis, implant design and size and surgical experience were reviewed. Results. All registries showed a significant decline of the use of MoMHRA. The AOAJRR reported a cumulative revision rate of 9.5% (95%CI: 8.9–10.1%) at 10 years for all hip resurfacings. Female gender, developmental dysplasia and femoral head sizes <49mm were significant risk factors with revision rates twice as high for head sizes <49mm compared to >55mm. In males, cumulative revision rate for all MoMHRA was 6.6% at 10 years and 7.8% at 13years with no difference in the age groups. ASR had significantly higher revision rates (23.9% at 7 years) compared to other designs. The Adept and the Mitch had the lowest revision rates at 7 years (3.6%). Cumulative revision rates for 10,750 BHR (males and females pooled) were 5.0% at 7 years, 6.9% at 10years and 8.4% at 13 years. Cumulative revision rates of THA in patients <55 years was 6.0% at 10 years and 9.4% at 13 years. Similar survivorship results were found in the Finnish, Swedish, New Zealand and RIPO registry. In the SHR, 10-year survivorship of THA in patients <50 was only around 87%. In the NJR, cumulative revision rates for all MoMHRA pooled were much less favourable (13% at 10 years – 22% in patients<50) but the revision probability of ASR was 30.4% compared to 9.0% for BHR. Surgical experience was also identified as an important determinant of success/failure. Discussion. Registries are now confirming good 10-year survivorship of certain MoMHRA designs with excellent results in males. Risk factors for revision are female gender, small head size, dysplasia and certain implant designs

Background. Current analysis of unicondylar knee replacements (UKR) by national registries is based on the pooled results of medial and lateral implants. Using data from the National Joint Registry for England and Wales (NJR) we aimed to determine the proportion of lateral UKR implanted, their survival and reason for failure in comparison to medial UKR. Methods. By combining information on the side of operation with component details held on the NJR we were able to determine implant laterality (medial vs. lateral) for 32,847 of the 35,624 (92%) UKR registered before December 2010. Kaplan Meier plots, Life tables and Cox' proportion hazards were used to compare the risk of failure for lateral and medial UKRs after adjustment for patient and implant covariates. Results. 2,052 (6%) UKR were inserted on the lateral side of the knee. The rates of survival at 5 years were 93.1% (95%CI 92.7 to 93.5) for medial and 93.0% (95%CI 91.1% to 94.9%) for lateral replacements (p=0.49). The rates of failure remained equivalent after adjustment for patient age, gender, ASA grade, indication for surgery and implant type using Cox's proportional hazards (HR=0.87, 95%CI 0.68 to 1.10, p=0.24). For medial implants covariates found to influence the risk of failure were patient age (p< 0.001) and ASA grade (p=0.04). Age similarly influenced the risk of failure for lateral UKRs. Implant design (Mobile versus Fixed bearing) did not influence the risk of failure in either the medial or lateral compartment. Aseptic loosening/lysis and unexplained pain were the main reasons for revision in both groups. Conclusion. The mid-term survival of medial and lateral UKRs are equivalent. This supports the on-going use of pooled data by registries for the reporting on unicondylar outcomes in the future