A first revision of the Andrena of Iraq (Hymenoptera, Andrenidae), with the description of two new species from Iraqi Kurdistan and additional records from surrounding countries.

Iraq is a large country in the Middle East region that borders both Turkey and Iran, countries known to host two of the largest bee faunas globally, as expected for a group of insects that favour dry to Mediterranean climates. Despite this huge regional species richness, the bee fauna of Iraq is chronically understudied and poorly known, both in relative and absolute terms. This is true for the hyper-speciose bee genus Andrena, for which only 17 species have been previously published for Iraq. This work is the first modern contribution to the revision of the Andrena fauna of Iraq. Based on new specimen collections in Duhok Governorate (Iraqi Kurdistan) during 2023, a revised total of 59 Andrena species for Iraq (42 species recorded for the first time) is presented, including the description of two new species: Andrena (Aciandrena) duhokensis Wood, sp. nov. and Andrena (Notandrena) baiocchii Wood, sp. nov. The unknown males of A. (Micrandrena) elam Wood, 2022, A. (Micrandrena) obsidiana Wood, 2022, and A. (Notandrena) ayna Wood, 2023 are described. Andrenabakrajoensis Amin & Mawlood, 2019, syn. nov. is synonymised with A. (Holandrena) variabilis Smith, 1853. Additional records are presented from nearby Middle Eastern countries, particularly Lebanon. These results highlight the fundamentally understudied nature of the Iraqi Andrena fauna.

The effects of chlorhexidine, povidone-iodine, and vancomycin on growth and biofilms of pathogens that cause prosthetic joint infections: an in vitro model.

BACKGROUND: Chlorhexidine gluconate (CHG) and povidone-iodine (PI) are commonly used to prevent prosthetic joint infection (PJI) during total joint replacement; however, their effective concentrations and impact on biofilms are not well defined. AIM: To determine: (1) the in vitro minimum inhibitory concentration of CHG and PI against model PJI-causing organisms and clinical isolates; (2) their impact on biofilm formation; (3) if there is a synergistic benefit to combining the two solutions; and (4) if adding the antibiotic vancomycin impacts antiseptic activity. METHODS: We measured in vitro growth and biofilm formation of Staphylococcus epidermidis, methicillin-sensitive and methicillin-resistant S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, as well as recent clinical isolates, in the presence of increasing concentrations of CHG and/or PI. Checkerboard assays were used to measure potential synergy of the solutions together and with vancomycin. FINDINGS: CHG and PI inhibited growth and biofilm formation of all model organisms tested at concentrations of 0.0004% and 0.33% or lower, respectively; highly dilute concentrations paradoxically increased biofilm formation. The solutions did not synergize with one another and acted independently of vancomycin. CONCLUSION: CHG and PI are effective at lower concentrations than typically used, establishing baselines to support further clinical trials aimed at optimizing wound disinfection. There is no synergistic advantage to using both in combination. Vancomycin is effective at inhibiting the growth of S. epidermidis and S. aureus; however, it stimulates P. aeruginosa biofilm production, suggesting in the rare case of P. aeruginosa PJI, it could exacerbate infection.

When does patient function "Plateau" after total joint arthroplasty? A cohort study.

PURPOSE: With over 100,000 procedures completed per year, hip and knee arthroplasty are two of the most common surgical procedures performed in Canada. There has been literature indicating that patient reported outcome measures (PROM) will start to plateau between six and 12 months. The purpose of this paper was to analyze the trajectory of PROMs following total hip and knee arthroplasty (THA and TKA), as well as assess the impact of any potential confounders on this trajectory. The central research question was: At what point do PROMS plateau among patients that undergo elective THA and TKA? METHODS: This study was a retrospective analysis of data from a prospective database. Patients were eligible if they had undergone an elective, primary THA/TKA with Oxford Scores recorded pre-operatively, and at least at two of the following four time points: six weeks, six months, one year, and two years. RESULTS: Mean pre-operative Oxford scores were 18.0 (7.8) for THA, and 20.1 (7.5) for TKA. For both THA and TKA, there were statistically significant interval improvements in Oxford scores from six weeks [THA: 33.8 (7.9)/TKA: 28.7 (7.8)] to six months [THA: 40.2 (7.3)/TKA: 35.9 (8.3)], and from six months to one year [THA: 41.0 (7.3)/TKA: 37.3 (8.4)], but not from one to two years [THA: 40.0 (8.5)/TKA: 36.4 (9.6)]. CONCLUSIONS: Patients undergoing either primary THA or TKA can expect clinically meaningful improvements in the first six months after surgery. Beyond this time point, there is a plateau in PROMs. These findings are important for both setting patient expectations in pre-operative discussions, and allowing surgeons to have a realistic understanding of their patients' expected post-operative course.

Taxonomic revision of the Stenodynerus fastidiosissimus species-group in Western Europe and North Africa (Hymenoptera: Vespidae: Eumeninae).

The fastidiosissimus species-group of Stenodynerus de Saussure, 1863 is revised in Western Europe and North Africa, combining morphological data and DNA barcoding. Six species are recognized: S. difficilis (Morawitz, 1867) stat. resurr. (= S. fastidiosissimus auct.), S. fastidiosissimus (de Saussure, 1855), S. laborans (Costa, 1882) stat. resurr., S. montanus Selis, sp. nov., S. muelleri (Dusmet, 1917) (= Stenodynerus gusenleitneri Giordani Soika, 1986 syn. nov.), and S. rufescens Giordani Soika, 1977 stat. nov. Lectotypes are designated for Odynerus fastidiosissimus de Saussure, 1855 and Odynerus insularis Andr, 1883 non Smith, 1859. A key for the identification of members of this species-group is provided. DNA barcodes are published for every species, representing the first available sequences for the fastidiosissimus species-group.

Factual corrections: Concerns and current evidence.

Factual corrections that target misinformation improve belief accuracy. They do so across a wide variety of countries, political beliefs and demographic characteristics. Instances of backfire, wherein exposure to corrections reduce accuracy, are exceedingly rare and may be an artifact of research design. The evidence regarding other common concerns is mixed. While the effects on corrections on belief are not permanent, they are not entirely ephemeral, either. With some exceptions, corrections mostly only affect belief accuracy, with minor to nonexistent influence on downstream attitudes and behaviors. While corrections are not unpopular among the public, limited available evidence suggests that those who see misinformation are exceedingly unlikely to see relevant corrections.

Neutrophil to Lymphocyte Ratio as an Indicator of Periprosthetic Joint Infection: A Retrospective Cohort Study.

INTRODUCTION: Periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) is a serious complication posing notable clinical implications for patients and substantial economic burdens. Neutrophil to lymphocyte ratio (NLR) is an emerging biomarker of inflammation, which may better predict PJI. The objective of this review was to evaluate NLR changes in patients with confirmed PJI, to compare NLR between an aseptic revision and a revision for PJI, and to establish whether an NLR of 2.45 is an appropriate cutoff for predicting infection. METHODS: A retrospective review of patients who underwent revision TJA for PJI at a single center between January 1, 2005, and December 31, 2018, was performed and compared with an aseptic cohort who underwent aseptic revision TJA. NLR was calculated from complete blood counts performed at index surgery and at the time of revision surgery. Receiver operating characteristic curves were analyzed, along with sensitivity, specificity, and positive and negative likelihood ratios. RESULTS: There were 89 patients included in each cohort. Mean NLR in patients who underwent revision for PJI was 2.85 (± 1.27) at the time of index surgery and 6.89 (± 6.64) at the time of revision surgery ( P = 0.017). Mean NLR in patients undergoing revision for PJI (6.89) was significantly higher than aseptic revisions (3.17; P < 0.001). DISCUSSION: In patients who underwent revision surgery for PJI, NLR was markedly elevated at time of revision compared with the time of index surgery. Because it is a cost-effective and readily available test, these findings suggest that NLR may be a useful triage test in the diagnosis of PJI. LEVEL OF EVIDENCE: Level III Diagnostic Study.

Management of Greater Trochanteric Pain Syndrome After Total Hip Arthroplasty: Practice Patterns and Surgeon Attitudes.

INTRODUCTION: Greater trochanteric pain syndrome (GTPS) or trochanteric bursitis is described as pain on the lateral side of the hip that does not involve the hip joint and can be elicited clinically by palpation over the greater trochanter. To date, there remains no consensus on clinical guidelines for either diagnosis or management of GTPS. METHODS: To understand the practice patterns, beliefs, and attitudes relating to the management of GTPS after total hip arthroplasty, a survey was developed and completed by Canadian arthroplasty surgeons. The final survey consisted of 23 questions divided into three sections: 1) screening questions; 2) demographic information; and 3) practice patterns, attitudes, and beliefs. RESULTS: Most surgeons use physical examination alone for diagnosis. A detailed analysis indicates that surgeons primarily treat GTPS with oral anti-inflammatories (57.1%), structured physiotherapy (52.4%), and steroid injections (45.2%). Management options are typically nonsurgical and comprise a combination of either unstructured or targeted physiotherapy, corticosteroid injections, or platelet-rich plasma. DISCUSSION: There remains an absence of clinical consensus for the diagnosis and management of GTPS after total hip arthroplasty. Physical examination is most often relied on, regardless of the availability of imaging aids. While common treatments of GTPS were identified, up to one-third of patients fail initial therapy.

Limited introgression from non-native commercial strains and signatures of adaptation in the key pollinator Bombus terrestris.

Insect pollination is fundamental for natural ecosystems and agricultural crops. The bumblebee species Bombus terrestris has become a popular choice for commercial crop pollination worldwide due to its effectiveness and ease of mass rearing. Bumblebee colonies are mass produced for the pollination of more than 20 crops and imported into over 50 countries including countries outside their native ranges, and the risk of invasion by commercial non-native bumblebees is considered an emerging issue for global conservation and biological diversity. Here, we use genome-wide data from seven wild populations close to and far from farms using commercial colonies, as well as commercial populations, to investigate the implications of utilizing commercial bumblebee subspecies in the UK. We find evidence for generally low levels of introgression between commercial and wild bees, with higher admixture proportions in the bees occurring close to farms. We identify genomic regions putatively involved in local and global adaptation, and genes in locally adaptive regions were found to be enriched for functions related to taste receptor activity, oxidoreductase activity, fatty acid and lipid biosynthetic processes. Despite more than 30 years of bumblebee colony importation into the UK, we observe low impact on the genetic integrity of local B. terrestris populations, but we highlight that even limited introgression might negatively affect locally adapted populations.

Marginalization Influences Access, Outcomes, and Discharge Destination Following Total Joint Arthroplasty in Canada's Universal Healthcare System.

BACKGROUND: The influence of socioeconomic status on outcomes following total joint arthroplasty (TJA) in the Canadian single-payer healthcare system is yet to be elucidated. The objective of the present study was to evaluate the impact of socioeconomic status on TJA outcomes. METHODS: This was a retrospective review of 7,304 consecutive TJA (4,456 knees and 2,848 hips) performed between January 1, 2001 and December 31, 2019. The primary independent variable was the average census marginalization index. The primary dependent variable was functional outcome scores. RESULTS: The most marginalized patients in both the hip and knee cohorts had significantly worse preoperative and postoperative functional scores. Patients in the most marginalized quintile (V) showed a decreased odds of achieving a minimal important difference in functional scores at 1-year follow-up (odds ratio [OR] 0.44; 95% confidence interval [CI] [0.20, 0.97], P = .043). Patients in the knee cohort in the most marginalized quintiles (IV and V) had increased odds of being discharged to an inpatient facility with an OR of 2.07 (95% CI [1.06, 4.04], P = .033) and OR of 2.57 (95% CI [1.26, 5.22], P = .009), respectively. Patients in the hip cohort in V quintile (most marginalized) had increased odds of being discharged to an inpatient facility with an OR of 2.24 (95% CI [1.02, 4.96], P = .046). CONCLUSION: Despite being a part of the Canadian universal single-payer healthcare system, the most marginalized patients had worse preoperative and postoperative function, and had increased odds of being discharged to another inpatient facility. LEVEL OF EVIDENCE: IV.

Correcting COVID-19 vaccine misinformation in 10 countries.

What can be done to reduce misperceptions about COVID-19 vaccines? We present results from experiments conducted simultaneously on YouGov samples in 10 countries (N = 10 600), which reveal that factual corrections consistently reduce false beliefs about vaccines. With results from these 10 countries, we find that exposure to corrections increases belief accuracy by 0.16 on a 4-point scale, while exposure to misinformation decreases belief accuracy by 0.09 on the same scale. We are unable to find evidence that either misinformation or factual corrections affect intent to vaccinate or vaccine attitudes. Our findings on effect duration are less conclusive; when we recontacted participants two weeks later, we observed 39% of the initial accuracy increase, yet this result narrowly misses conventional thresholds of statistical significance (p = 0.06). Taken together, our results illustrate both the possibilities and limitations of factual corrections. Evidence from 10 highly diverse populations shows that exposure to factual information reduces belief in falsehoods about vaccines, but has minimal influence on subsequent behaviours and attitudes.

Routine use of antibiotic-laden bone cement in total knee arthroplasty is a cost-effective practice in the single-payer healthcare system.

PURPOSE: The purpose of this study was to determine the cost-effectiveness of antibiotic-laden bone cement (ALBC) in primary total knee arthroplasty (TKA) from the perspective of a single-payer healthcare system. METHODS: A cost-utility analysis (CUA) was performed over a 2-year time horizon comparing primary TKA with either ALBC or regular bone cement (RBC) from the perspective of the single-payer Canadian healthcare system. All costs were in 2020 Canadian dollars. Health utilities were in the form of quality-adjusted life years (QALYs). Model inputs for cost, utilities and probabilities were derived from the literature as well as regional and national databases. One-way deterministic sensitivity analysis was performed. RESULTS: Primary TKA with ALBC was found to be more cost-effective compared to primary TKA with RBC with an incremental cost-effectiveness ratio (ICER) of -3,637.79 CAD/QALY. The use of routine ALBC remained cost-effective even with cost increases of up to 50% per bag of ALBC. TKA with ALBC was no longer cost-effective if the rate of PJI following this practice increased 52%, or the rate of PJI following the use of RBC decreased 27%. CONCLUSIONS: The routine use of ALBC in TKA is a cost-effective practice in the single-payer Canadian healthcare system. This remains to be the case even with a 50% increase in the cost of ALBC. Policy makers and hospital administrators of single-payer healthcare systems can leverage this model to inform their local funding policies. Future prospective reviews and randomized controlled trials from the perspective of various healthcare models can further shed light on this issue. LEVEL OF EVIDENCE: III.

Efficacy of hydrofibre dressing following total joint arthroplasty: a meta-analysis of randomised controlled trials.

INTRODUCTION: In the United States, over 1,000,000 total joint arthroplasty (TJA) surgeries are performed annually and has been forecasted that this number will exceed 4,000,000 by the year 2030. Many different types of dressing exist for use in TJA surgery, and it is unclear if any of the newer, hydrofibre dressings are superior to traditional dressings at reducing rates of infections or improving wound healing. Thus, the aim of this systematic review and meta-analysis was to assess the impact of hydrofiber dressings on reducing complications. METHODS: A systematic review and meta-analysis was performed using the online databases MEDLINE and the Cochrane Library. Randomized controlled trials (RCTs) comparing hydrofibre dressings to a standard dressing were included. Summary measures are reported as odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs). Our primary outcome was prosthetic joint infection (PJI). Secondary outcomes included blisters, dressing changes and wound irritation. RESULTS: 5 RCTs were included. Hydrofibre dressing had no observable effect on PJI or wound irritation (OR 0.53; 95% CI, 0.14-1.98; p = 0.35). Hydrofibre dressings reduced the rate of blisters (OR 0.36; 95% CI, 0.14-0.90; p = 0.03) and number of dressing changes (MD -1.89; 95% CI, -2.68 to -1.11). CONCLUSIONS: In conclusion, evidence suggests hydrofibre dressings have no observable effect on PJI and wound irritation. Evidence for reduction in blisters and number of dressings is modest given wide CIs and biased trial methodologies. Use of hydrofibre dressings should be considered inconclusive for mitigating major complications in light of current best evidence.

Causes and predictors of failed same-day home discharge following primary hip and knee total joint arthroplasty: a Canadian perspective.

PURPOSE: Same-day home (SDH) discharge in total joint arthroplasty (TJA) has increased in popularity in recent years. The objective of this study was to evaluate the causes and predictors of failed discharges in planned SDH patients. METHODS: A consecutive cohort of patients who underwent total knee (TKA) or total hip arthroplasty (THA) that were scheduled for SDH discharge between 01 April 2019 and 31 March 2021 were retrospectively reviewed. Patient demographics, causes of failed discharge, perioperative variables, 30-day readmissions and 6-month reoperation rates were collected. Multivariate regression analysis was undertaken to identify independent predictors of failed discharge. RESULTS: The cohort consisted of 527 consecutive patients. 101 (19%) patients failed SDH discharge. The leading causes were postoperative hypotension (20%) and patients who were ineligible for the SDH pathway (19%). 2 individual surgeons, later operative start time (OR 1.3; 95% CI, 1.15-1.55; p = 0.001), ASA class IV (OR 3.4; 95% CI, 1.4-8.2; p = 0.006) and undergoing a THA (OR 2.0; 95% CI, 1.2-3.1, p = 0.004) were independent predictors of failed SDH discharge. No differences in age, BMI, gender, surgical approach or type of anaesthetic were found (p > 0.05). The 30-day readmission or 6-month reoperation were similar between groups (p > 0.05). CONCLUSIONS: Hypotension and inappropriate patient selection were the leading causes of failed SDH discharge. Significant variability existed between individual surgeons failed discharge rates. Patients undergoing a THA, classified as ASA IV or had a later operative start time were all more likely to fail SDH discharge.

The quality of diagnostic studies used for the diagnostic criteria of periprosthetic joint infections.

BACKGROUND: Although periprosthetic joint infection (PJI) is a serious complication following a total joint arthroplasty procedure, there remains uncertainty regarding the diagnosis of PJI due to the lack of a globally accepted, standardized definition. The goal of this review is to critically analyze the quality of the evidence used for the novel 2018 MSIS PJI definition and identify gaps and limitations with using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. METHODS: References from the modified 2018 MSIS definition for PJI by Parvizi et al. were retrieved and manually reviewed. A total of 11 studies were assessed using a validated QUADAS-2 tool. RESULTS: Many included studies had an unclear or high risk of bias for the Index Test domain due to a lack of blinding and lack of prespecified thresholds. A majority of studies utilized Youden's J statistic to optimize the thresholds which may diminish external validity. Likewise, several studies were assessed to have an unclear and high risk of bias for the Flow and Timing domain primarily due to a lack of reporting and a large number of exclusions. Overall, there was a low risk of bias for the choice of reference standard, its conduct and interpretation, as well as for the Patient Selection domain. CONCLUSION: Although the literature used for the MSIS 2018 PJI definition is fraught with potential sources of bias, there may be a trend toward an improvement in the quality of evidence when compared to the earlier definition of PJI.

Risk factors for recurrence of periprosthetic joint infection following operative management: a cohort study with average 5-year follow-up.

Background: Periprosthetic joint infections (PJIs) remain challenging to eradicate even after surgical management, which in most cases involves either debridement, antibiotics and implant retention (DAIR) or single- or two-staged revision. The purpose of this study is to determine predictors of PJI recurrence after operative management for PJI, and to determine differences in recurrence-free survival between DAIR and staged revision. Methods: This is a retrospective analysis of prospectively collected data of revision hip and knee arthroplasty surgeries due to PJI between 2011 and 2018 at an academic hospital. Any patient undergoing revision surgery for PJI was included except if the index surgery information was unknown. The primary outcome was confirmed PJI recurrence. Multivariable logistic regression analysis was utilized to determine the relationship between the predictor variables and outcome variable. Log rank testing was used to compare recurrence-free survival between DAIR and staged revision. Results: A total of 89 patients (91 joints) underwent revision surgery due to PJI. Younger age and presence of a sinus tract were statistically significant for risk of PJI recurrence. A multivariable logistic regression model including both variables was significant for predicting recurrence of PJI (χ2=10.2, P=0.006). Survival was not significantly different between patients who underwent DAIR versus a staged revision. Conclusions: Younger patients and those with a chronic sinus tract are at significantly higher risk of recurrent PJI. This study also demonstrated that PJI can be successfully managed in the majority of cases with DAIR or staged revision.

The new annotated checklist of the wild bees of Europe (Hymenoptera: Anthophila).

At a time when nature conservation has become essential to ensure the long-term sustainability of our environment, it is widely acknowledged that conservation actions must be implemented within a solid taxonomic framework. In preparation for the upcoming update of the IUCN Red List, we here update the European checklist of the wild bees (sensu the IUCN geographical framework). The original checklist, published in 2014, was revised for the first time in 2017. In the present revision, we add one genus, four subgenera and 67 species recently described, 40 species newly recorded since the latest revision (including two species that are not native to Europe), 26 species overlooked in the previous European checklists and 63 published synonymies. We provide original records for eight species previously unknown to the continent and, as original taxonomic acts, we provide three new synonyms, we consider two names as nomina nuda, ten names as nomina dubia, three as species inquirenda, synonymize three species and exclude 40 species from the previous checklist. Around a hundred other taxonomic changes and clarifications are also included and discussed. The present work revises the total number of genera for IUCN Europe to 77 and the total number of species to 2,138. In addition to specifying the taxonomic changes necessary to update the forthcoming Red List of European bees, we discuss the sampling and taxonomic biases that characterise research on the European bee fauna and highlight the growing importance of range expansions and species invasions.

Time and skeptical opinion content erode the effects of science coverage on climate beliefs and attitudes.

Although experiments show that exposure to factual information can increase factual accuracy, the public remains stubbornly misinformed about many issues. Why do misperceptions persist even when factual interventions generally succeed at increasing the accuracy of people's beliefs? We seek to answer this question by testing the role of information exposure and decay effects in a four-wave panel experiment (n = 2,898 at wave 4) in which we randomize the media content that people in the United States see about climate change. Our results indicate that science coverage of climate change increases belief accuracy and support for government action immediately after exposure, including among Republicans and people who reject anthropogenic climate change. However, both effects decay over time and can be attenuated by exposure to skeptical opinion content (but not issue coverage featuring partisan conflict). These findings demonstrate that the increases in belief accuracy generated by science coverage are short lived and can be neutralized by skeptical opinion content.

Diagnosing Periprosthetic Joint Infection: a Scoping Review.

PURPOSE OF REVIEW: The goal of this review is to provide an up to date understanding of the utility and limitations of the current tests utilized in the diagnosis of periprosthetic joint infection (PJI) in total knee and hip arthroplasty. RECENT FINDINGS: Despite the growth in literature surrounding PJI diagnosis, there remains challenges in establishing a diagnosis of PJI. A combination of clinical, serum, and synovial tests and microbiologic and histologic examinations can yield a diagnosis in the majority of cases. Novel molecular and imaging studies may be beneficial for indeterminant cases. A number of emerging diagnostic tests have been proposed and may be incorporated into diagnostic algorithms in the future. Recently proposed stepwise diagnostic algorithms have shown high sensitivity and specificity. The diagnosis of PJI remains challenging due to a lack of tests that can definitively rule out infection. Diagnosis and investigations should occur in a stepwise fashion. There has been a plethora of new diagnostic tests introduced in attempts to improve the accuracy of diagnostic algorithms. The definition and algorithms for the diagnoses of PJI will continue to evolve as new techniques and tests are introduced.

Intermediate to Long-Term Outcomes and Causes of Aseptic Failure of an At-Risk Femoral Stem.

BACKGROUND: The Accolade TMZF is a tapered-wedge cementless metaphyseal-coated femoral stem that was widely utilized from 2002 to 2012. In recent years, there have been reports of early catastrophic failure of this implant. The purposes of the present study were to establish the long-term survival of this stem and to analyze patients who underwent aseptic revision to understand the causes and risk factors for failure. METHODS: We retrospectively reviewed the records of all patients who had undergone primary total hip arthroplasty with use of an Accolade TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented. Survivorship analysis was performed with use of Kaplan-Meier curves to determine the overall and aseptic survival rates at the time of the latest follow-up. Patient and implant factors commonly associated with aseptic failure were extracted, and a Cox proportional hazards model was used. RESULTS: A consecutive series of 2,609 patients who had undergone unilateral primary total hip arthroplasty with use of an Accolade TMZF femoral stem were included. The mean time from the primary procedure was 11.3 years (range, 0 days to 19.4 years). The cumulative survival rate was 95.5% ± 0.1% at the time of the latest follow-up. One hundred and seven patients underwent revision surgery, with aseptic loosening of the femoral component being the most common cause of aseptic failure in this cohort (33 of 2,609; 1.3%). Smaller femoral size and larger femoral head offset were independent risk factors for aseptic failure. CONCLUSIONS: To our knowledge, this is the largest series representing the longest follow-up of this tapered-wedge cementless femoral implant. Despite early concerns, the Accolade TMZF stem had excellent survivorship in this cohort. Trunnionosis as the cause for revision surgery was rare. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Are Functional Outcomes of a Total Hip Arthroplasty Predictive of a Contralateral Total Hip Arthroplasty: A Retrospective Cohort Study.

BACKGROUND: Current literature suggests that 8%-35% of patients undergoing total hip arthroplasty (THA) undergo a subsequent contralateral THA. This study aims to determine if functional outcomes after primary THA predict outcomes in the subsequent primary THA of the contralateral side. METHODS: A retrospective cohort of patients undergoing staged bilateral primary THA was reviewed. The Oxford Hip Score (OHS) was utilized as the functional outcome measurement tool and was assessed preoperatively and at one year postoperatively. The minimal clinically important difference (MCID) was assessed. Based on the first-side THA one-year outcomes, the odds of maintaining an MCID, or not, for the second-side THA were determined. RESULTS: The study cohort consisted of 551 patients and 1102 primary THAs. The average postoperative OHSs were similar after the first and second THA. Patients achieving the MCID with the first-side surgery were 2.6 times (95% confidence interval 1.0 to 6.64, P = .04) more likely to achieve the MCID for the second-side surgery than patients failing to reach the MCID for their first-side surgery. After the first THA, 29 (5.3%) patients failed to reach the predefined MCID for the OHS compared with 54 (9.8%) patients undergoing their second THA (odds ratio: 1.96 [95% confidence interval: 1.23 to 3.1], χ2 = 8.14, P = .005). CONCLUSIONS: Functional outcomes after the first THA are predictive of functional outcomes of the second THA. Patients are more likely to achieve a clinically significant improvement after their first THA related to higher preoperative OHSs before the second THA.