Aims. The aim of this study was to estimate the 90-day periprosthetic joint infection (PJI) rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA) for osteoarthritis (OA). Methods. This was a data linkage study using the New South Wales (NSW) Admitted Patient Data Collection (APDC) and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), which collect data from all public and private hospitals in NSW, Australia. Patients who underwent a TKA or THA for OA between 1 January 2002 and 31 December 2017 were included. The main outcome measures were 90-day incidence rates of hospital readmission for: revision arthroplasty for PJI as recorded in the AOANJRR; conservative definition of PJI, defined by T84.5, the PJI diagnosis code in the APDC; and extended definition of PJI, defined by the presence of either T84.5, or combinations of diagnosis and procedure code groups derived from recursive binary partitioning in the APDC. Results. The mean 90-day revision rate for infection was 0.1% (0.1% to 0.2%) for TKA and 0.3% (0.1% to 0.5%) for THA. The mean 90-day PJI rates defined by T84.5 were 1.3% (1.1% to 1.7%) for TKA and 1.1% (0.8% to 1.3%) for THA. The mean 90-day PJI rates using the extended definition were 1.9% (1.5% to 2.2%) and 1.5% (1.3% to 1.7%) following TKA and THA, respectively. Conclusion. When reporting the revision arthroplasty for infection, the AOANJRR substantially underestimates the rate of PJI at 90 days. Using combinations of infection codes and PJI-related surgical procedure codes in linked hospital administrative databases could be an alternative way to monitor PJI rates. Cite this article: Bone Joint J 2022;104-B(9):1060–1066

The primary objective is to compare revision rates for lumbar disc replacement (LDR) and fusion at the same or adjacent levels in Ontario, Canada. The secondary objectives include acute complications during hospitalization and in 30 days, and length of hospital stay. A population-based cohort study was conducted using health administrative databases including patients undergoing LDR or single level fusion between October 2005 to March 2018. Patients receiving LDR or fusion were identified using physician claims recorded in the Ontario Health Insurance Program database. Additional details of surgical procedure were obtained from the Canadian Institute for Health Information hospital discharge abstract. Primary outcome measured was presence of revision surgery in the lumbar spine defined as operation greater than 30 days from index procedure. Secondary outcomes were immediate/ acute complications within the first 30 days of index operation. A total of 42,024 patients were included. Mean follow up in the LDR and fusion groups were 2943 and 2301 days, respectively. The rates of revision surgery at the same or adjacent levels were 4.7% in the LDR group and 11.1% in the fusion group (P=.003). Multivariate analysis identified risk factors for revision surgery as being female, hypertension, and lower surgeon volume. More patients in the fusion group had dural tears (p<.001), while the LDR group had more “other” complications (p=.037). The LDR group had a longer mean hospital stay (p=.018). In this study population, the LDR group had lower rates of revision compared to the fusion group. Caution is needed in concluding its significance due to lack of clinical variables and possible differences in indications between LDR and posterior decompression and fusion

Immigrated Canadians make up approximately 20% of the total population in Canada, and 30% of the population in Ontario. Despite universal health coverage and an equal prevalence of severe arthritis in immigrants relative to non-immigrants, the former may be underrepresented amongst arthroplasty recipients secondary to challenges navigating the healthcare system. The primary aim of this study was to determine if utilization of arthroplasty differs between immigrant populations and persons born in Canada. The secondary aim was to determine differences in outcomes following total hip and knee arthroplasty (THA and TKA, respectively). This is a retrospective population-based cohort study using health administrative databases. All patients aged ≥18 in Ontario who underwent their first primary elective THA or TKA between 2002 and 2016 were identified. Immigration status for each patient was identified via linkage to the ‘Immigration, Refugee and Citizenship Canada’ database. Outcomes included all-cause and septic revision surgery within 12-months, dislocation (for THA) and total post-operative case cost and were compared between groups. Cochrane-Armitage Test for Trend was utilized to determine if the uptake of arthroplasty by immigrants changed over time. There was a total of 186,528 TKA recipients and 116,472 THA recipients identified over the study period. Of these, 10,193 (5.5%) and 3,165 (2.7%) were immigrants, respectively. The largest proportion of immigrants were from the Asia and Pacific region for those undergoing TKA (54.0%) and Europe for THA recipients (53.4%). There was no difference in the rate of all-cause revision or septic revision at 12 months between groups undergoing TKA (p=0.864, p=0.585) or THA (p=0.527, p=0.397), respectively. There was also no difference in the rate of dislocations between immigrants and people born in Canada (p=0.765, respectively). Despite having similar complication rates and costs, immigrants represent a significantly smaller proportion of joint replacement recipients than they represent in the general population in Ontario. These results suggest significant underutilization of surgical management for arthritis among Canada's immigrant populations. Initiatives to improve access to total joint arthroplasty are warranted

Timely and competent treatment of paediatric fractures is paramount to a healthy future working population. Anecdotal evidence suggests that children travel greater distances to obtain care compared to adults causing economic and geographic inequities. This study aims to qualify the informal regionalization of children's fracture care in Ontario. The results could inform future policy on resource distribution and planning of the provincial health care system. A retrospective cohort study was conducted examining two of the most common paediatric orthopaedic traumatic injuries, femoral shaft and supracondylar humerus fractures (SCH), in parallel over the last 10 years (2010-2020) using multiple linked administrative databases housed at the Institute for Clinical Evaluative Sciences (ICES) in Toronto, Ontario. We compared the distance travelled by these pediatric cohorts to clinically equivalent adult fracture patterns (distal radius fracture (DR) and femoral shaft fracture). Patient cohorts were identified based on treatment codes and distances were calculated from a centroid of patient home forward sortation area to hospital location. Demographics, hospital type, and closest hospital to patient were also recorded. For common upper extremity fracture care, 84% of children underwent surgery at specialized centers which required significant travel (44km). Conversely, 67% of adults were treated locally, travelling a mean of 23km. Similarly, two-thirds of adult femoral shaft fractures were treated locally (mean travel distance of 30km) while most children (84%) with femoral shaft fractures travelled an average of 63km to specialized centers. Children who live in rural areas travel on average 51km more than their adult rural-residing counterparts for all fracture care. Four institutions provide over 75% of the fracture care for children, whereas 22 institutions distribute the same case volume in adults.?. Adult fracture care naturally self-organizes with proportionate distribution without policy-directed systemization. There is an unplanned concentration of pediatric fracture care to specialized centers in Ontario placing undue burden on pediatric patients and inadvertently stresses the surgical resources in a small handful of hospitals. In contrast, adult fracture care naturally self-organizes with proportionate distribution without policy-directed systemization. Patient care equity and appropriate resource allocation cannot be achieved without appropriate systemization of pediatric fracture care

This study aimed to determine if multiple failed closed reductions (CRs) prior to fixation of distal radius fracture is associated with the odds of complication-related reoperation up to two years post fracture. We identified all distal radius fracture patients aged 18 or older between the years of 2003-2016 in Ontario, Canada from linked administrative databases. We used procedural and fee codes to identify patients who underwent primary outpatient surgical fixation between 8 and 14 days post fracture, and grouped patients by the number of CRs they underwent prior to definitive fixation. We excluded patients who underwent fixation within 7 days of their fracture to exclude more complex fracture types and/or patients who required more immediate surgery. We grouped patients according to the number of CRs they underwent prior to definitive fixation. We used intervention and diagnostic codes to identify reoperations within two years of fixation. We used multi-level multivariable logistic regression to compare the association between the number of CRs and reoperation while accounting for clustering at the surgeon level and adjusting for other relevant covariables. We performed an age-stratified analysis to determine if the association between the number of CRs and reoperation differed by patient age. We identified 5,464 patients with distal radius fractures managed with outpatient fixation between 8 and 14 days of their fracture. A total of 1,422 patients (26.0%) underwent primary surgical fixation (mean time to fixation 10.6±2.0 days), while 3,573 (65.4%) underwent secondary fixation following one failed CR (mean time to fixation 10.1±2.2 days, time to CR 0.3±1.2 days), and 469 (8.6%) underwent fixation following two failed CRs (mean time to fixation 10.8±2.2 days, time to first CR 0.0±0.1 days, time to second CR 4.7±3.0 days). The CR groups had higher proportions of female patients compared to the primary group, and patients who underwent two failed CRs were more likely to be fixed with a plate (vs. wires or pins). The unadjusted proportion of reoperations was significantly higher in the group who underwent two failed CRs (7.5%) compared to those who underwent primary fixation (4.4%), and fixation following one failed CR (4.9%). Following covariable adjustment, patients who underwent two failed CRs had a significantly higher odds of reoperation (odds ratio [OR] 1.72 [1.12-2.65]) compared to those who underwent primary fixation. This association appeared to worsen for patients over the age of 60 (OR 3.93 [1.76-8.77]). We found no significant difference between the odds of reoperation between patients who underwent primary fixation vs. secondary fixation following one failed CR. We found that patients with distal radius fractures who undergo multiple CRs prior to definitive fixation have a significantly higher odds of reoperation compared to those who undergo primary fixation, or fixation following a single CR. This suggests that surgeons should offer fixation if indicated following a single failed CR rather than attempt multiple closed reductions. Prospective studies are required to confirm these findings

Population-based studies from the United States have reported that sarcoma patients living in rural areas or belonging to lower socioeconomic classes experience worse overall survival; however, the evidence is not clear for universal healthcare systems where financial resources should theoretically not affect access to standard of care. The purpose of this study was to determine the survival outcomes of soft-tissue sarcoma (STS) patients treated in Ontario, Canada over 23 years and determine if the patient's geographic location or income quintile are associated with survival. We performed a population-based cohort study using linked administrative databases of patients diagnosed with STS between 1993 – 2015. The Kaplan-Meier method was used to estimate 2, 5, 10, 15 and 20-year survival stratified by age, stage and location of tumor. We estimated survival outcomes based on the patient's geographic location and income quintile. The Log-Rank test was used to detect significant differences between groups. If groups were significantly different, a Cox proportional hazards model was used to test for interaction effects with other patient variables. We identified 8,896 patients with biopsy-confirmed STS during the 23-year study period. Overall survival following STS diagnosis was 70% at 2 years, 59% at 5 years, 50% at 10 years, 43% at 15 years, and 38% at 20 years. Living in a rural location (p=0.0028) and belonging to the lowest income quintile (p<0.0001) were independently associated with lower overall survival following STS diagnosis. These findings were robust to tests of interaction with each other, age, gender, location of tumor and stage of disease. This population-based cohort study of 8,896 STS patients treated in Ontario, Canada over 23 years reveals that patients living in a rural area and belonging to the lowest income quintile are at risk for decreased survival following STS diagnosis. We extend previous STS survival reporting by providing 15 and 20-year survival outcomes stratified by age, stage, and tumor location

Introduction. Elective surgery elicits a systemic immune response and may result in immunosuppression in certain patients. It is currently unknown whether patients are at an increased risk for viral infection and associated illness in the immediate postoperative period following total joint arthroplasty. This question has become more important given the ongoing coronavirus disease 2019 (COVID-19) pandemic. Methods. We analyzed 3 large administrative datasets (Medicare 5% and 100% standard analytic files, Humana claims database) to identify patients who underwent total knee arthroplasty (TKA) and total hip arthroplasty (THA) from 2005 to 2013. The influenza vaccination status of each patient was defined using the presence or absence of a code for vaccination. The incidence of a flu diagnosis was recorded in both vaccinated and unvaccinated patients at 1 month, 3 months, and 6 months following the date of surgery and was compared to a cohort of vaccinated patients who did not undergo surgery. Results. The incidence of postoperative influenza diagnoses codes in TKA and THA patients were similar to that of vaccinated patients who did not undergo TJA at all time points. The results were largely consistent across all three datasets. Conclusion. Large administrative databases fail to show an increased incidence of influenza codes in patients who have recently undergone total joint arthroplasty. While the lack of signal is reassuring and provides evidence, these findings are limited by the nature of large administrative datasets and the accuracy of coding for influenza. Further studies will be necessary to fully understand an individual patient's postoperative risk for contracting a viral illness

Introduction. With the widespread legalization of cannabis across the United States, well-powered studies evaluating the impact of cannabis use disorder on outcomes following primary total hip arthroplasty are warranted. Therefore, the aim of this study was to determine whether cannabis use disorder has an effect on patients who undergo primary hip arthroplasty in terms of: 1) hospital lengths of stay (LOS); 2) medical complications; 3) implant-related complications; and 4) costs of care. Methods. Using an administrative database, patients who underwent primary total hip arthroplasty and had cannabis use disorder were matched to a cohort who did not in a 1:5 ratio by age, sex, and various medical comorbidities. This yielded 44,154 patients; 7,361 who had cannabis use disorder and 36,793 who did not. Variables for analysis included postoperative LOS, 90-day medical complications, 2-year implant-related complications, and 90-day costs of care. Mann-Whitney-U tests were used to compare LOS and costs. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of developing complications. A p-value less than 0.005 was considered statistically significant. Results. The study found that patients who had cannabis use disorder had significantly longer in-hospital LOS (4 vs. 3 days, p<0.0001) compared to the matched cohort. Additionally, study patients were found to have significantly higher incidences and odds of developing medical (11.23 vs. 4.82%; OR: 1.47, p<0.0001) and implant-related complications (18.14 vs. 8.60%; OR: 1.50, p<0.0001). Moreover, patients who had cannabis use disorder incurred significantly higher 90-day episode of care costs ($24,585.96 vs. $23,725.93, p<0.0001). Conclusions. With the growing rates of cannabis use, this study can allow orthopaedists and other healthcare professionals to educate cannabis use disorder on the possible outcomes following their total hip arthroplasty. It should be appreciated that cannabis use disorder is associated with longer hospital stays, increased complication rates, and higher costs following primary THA

The purpose of this study was to evaluate mortality following delay to surgery in hip fractures in the province of Ontario. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 were identified using administrative databases. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95%CI), with similar results at three months and one year. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for hip fractures. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for patients with fractured hips. This finding will have far reaching implications for the allocation of health resources in the future. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 in the Province of Ontario were identified using administrative databases and the provincial mortality database. Multivariable logistic regression models were used to adjust for age, gender, medical comorbidity, type of hip fracture, and teaching status of the treating hospital. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95% CI). The adjusted odds of in-hospital mortality increased as the delay to surgery lengthened from a factor of 1.2 [95% CI] with a one day delay to a factor of 1.5 [95% CI] for a delay over two days as compared with patients operated within twenty-four hours. Similar relationships were observed at three months and one year. Even when considering only healthy patients, < 70 years old with no comorbid conditions, the relationship between mortality and surgical delay remained significant (p < 0.0001), suggesting that surgical delay was unlikely to be caused by patient factors alone

The purpose of this study was to evaluate mortality following delay to surgery in hip fractures in the province of Ontario. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 were identified using administrative databases. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95%CI), with similar results at three months and one year. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for hip fractures. To evaluate mortality following delay to surgery in hip fractures in the province of Ontario. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for patients with fractured hips. This finding will have far reaching implications for the allocation of health resources in the future. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 in the Province of Ontario were identified using administrative databases and the provincial mortality database. Multivariable logistic regression models were used to adjust for age, gender, medical comorbidity, type of hip fracture, and teaching status of the treating hospital. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95% CI). The adjusted odds of in-hospital mortality increased as the delay to surgery lengthened from a factor of 1.2 [95% CI] with a one day delay to a factor of 1.5 [95% CI] for a delay over two days as compared with patients operated within twenty-four hours. Similar relationships were observed at three months and one year. Even when considering only healthy patients, < seventy years old with no comorbid conditions, the relationship between mortality and surgical delay remained significant (p < 0.0001), suggesting that surgical delay was unlikely to be caused by patient factors alone

Surgical management of acetabular fractures in older patients remains controversial. The purpose of this study is to compare outcomes of primary THA with outcomes after THA for acute acetabular fractures (aTHA) as well as outcomes following delayed THA (dTHA) following prior acetabular fracture. We analyzed data from a large, national administrative claims database containing diagnostic, procedural, and demographic records from over 157 million patients. We identified all patients undergoing primary total hip arthroplasty THA continuously enrolled in the database at least 2 years prior and after the index procedure. Patients with an initial diagnostic code for acetabular fracture occurring the same day as the THA were classified as acute acetabular fractures. Patients with an initial acetabular fracture diagnostic code occurring at least 6 months before THA were classified as chronic acetabular fractures. The comparator group was patients undergoing THA with no history of acetabular fracture. There were 426,734 patients undergoing primary THA, 235 patients undergoing aTHA and 1,255 patients undergoing dTHA. Patients with an aTHA had higher complication rates, including revisions (9.8% vs 5.6%,), dislocations (8.9% vs 6.4%), and periprosthetic fracture (5.1% vs 2.3%) compared to dTHA. After adjusting for age, sex, region, and comorbidities, receiving an aTHA increased the odds of revision (OR = 3.65 [95% CI: 2.30–5.49]), dislocation (OR = 4.09 [95% CI: 2.53–6.27]), and periprosthetic fracture (OR = 4.29 [95% CI: 2.26–7.36]) compared to primary THA. Receiving a dTHA significantly increased the odds of revision (adjusted OR = 1.80 [95% CI: 1.40–2.27]), dislocation (adjusted OR = 2.50 [95% CI: 1.97–3.13]), and periprosthetic fracture (adjusted OR = 1.99 [95% CI: 1.34–2.83]) compared to primary THA. Patients undergoing aTHA in the treatment of an acetabular fracture have significantly increased rates of revision, periprosthetic fracture, and dislocation compared to dTHA and primary THA

Introduction. The practice of overlapping surgery has been increasing in the delivery of orthopaedic care, aiming to provide efficient, high-quality care. However, there have been concerns about the safety of this practice. The purpose of this study is to examine safety and efficacy of a model of partially overlapping surgery that we termed “the swing room” in practice in primary hip and knee arthroplasty. Methods. A retrospective review of prospectively collected data using an administrative database was carried out on patients who underwent primary unilateral total hip and total knee arthroplasty from 2006 to 2017 at two sites of one academic center staffed by four arthroplasty surgeons. All revisions and bilateral primary procedures were excluded. Cases were stratified as overlapping or non-overlapping. Overlapping was defined when a surgeon had access to two operating rooms with two teams, and non-overlapping was defined as when a surgeon only had access to a single operating room on a particular day. Patient demographic characteristics, operating room time, procedure time, length of stay, Postoperative complications within 30 days of the procedure, unplanned hospital readmissions, unplanned reoperations, and emergency department visits were collected. The Fisher's exact Wilcoxon rank-sum test and logistic regression analysis were used for statistical analysis. Results. Of 12,225 cases were performed at our institution, 10600 cases (86.7%) were overlapping, and 1625 cases (13.3%) were non-overlapping. There was no difference in the mean age, sex, BMI, side and length of stay between patients who underwent overlapping surgery and those who underwent non- overlapping surgery. Operating room time was significantly shorter in the overlapping surgery group 58.2 min compared to the non-overlapping group 62.8 min p <0.001. There was no significant difference in complications (1.4% non-overlapping vs. 1.3% overlapping; p =0.801) and 30 days readmission (2.9% non-overlapping vs. 3.4% overlapping; p=0.300). Conclusion. The new “swing room” model yields similar short-term outcomes with no increase in complication rates compared to standard single room surgery in primary hip and knee arthroplasty practice. For any tables or figures, please contact the authors directly

Background. The advent of value-based conscientiousness and rapid-recovery discharge pathways presents surgeons, hospitals, and payers with the challenge of providing the same total hip arthroplasty episode of care in the safest and most economic fashion for the same fee, despite patient differences. Various predictive analytic techniques have been applied to medical risk models, such as sepsis risk scores, but none have been applied or validated to the elective primary total hip arthroplasty (THA) setting for key payment-based metrics. The objective of this study was to develop and validate a predictive machine learning model using preoperative patient demographics for length of stay (LOS) after primary THA as the first step in identifying a patient-specific payment model (PSPM). Methods. Using 229,945 patients undergoing primary THA for osteoarthritis from an administrative database between 2009– 16, we created a naïve Bayesian model to forecast LOS after primary THA using a 3:2 split in which 60% of the available patient data “built” the algorithm and the remaining 40% of patients were used for “testing.” This process was iterated five times for algorithm refinement, and model performance was determined using the area under the receiver operating characteristic curve (AUC), percent accuracy, and positive predictive value. LOS was either grouped as 1–5 days or greater than 5 days. Results. The machine learning model algorithm required age, race, gender, and two comorbidity scores (“risk of illness” and “risk of morbidity”) to demonstrate excellent validity, reliability, and responsiveness with an AUC of 0.87 after five iterations. Hospital stays of greater than 5 days for THA were most associated with increased risk of illness and risk of comorbidity scores during admission compared to 1–5 days of stay. Conclusions. Our machine learning model derived from administrative big data demonstrated excellent validity, reliability, and responsiveness after primary THA while accurately predicting LOS and identifying two comorbidity scores as key value-based metrics. Predictive data has the potential to engender a risk-based PSPM prior to primary THA and other elective orthopaedic procedures

Total hip arthroplasty (THA) is one of the most successful and effective treatments for advanced hip osteoarthritis (OA). Over the last 5 years, Canada has seen a 17.8% increase in the number of hip replacements performed annually, and that number is expected to grow along with the aging Canadian population. However, the rise in THA surgery is associated with an increased number of patients at risk for the development of an infection involving the joint prosthesis and adjacent deep tissue – periprosthetic joint infections (PJI). Despite improved hygiene protocols and novel surgical strategies, PJI remains a serious complication. No previous population-based studies has investigated PJI risk factors using a time-to-event approach and none have focused exclusively on patients undergoing THA for primary hip OA. The purpose of this study is to determine risk factors for PJI after primary THA for OA using a large population-based database collected over 15 years. Our secondary objective is to determine the incidence of PJI, the time to PJI following primary THA, and if PJI rates have changed in the past 15 years. We performed a population-based cohort study using linked administrative databases in Ontario, Canada in accordance with RECORD and STROBE guidelines. All primary total hip replacements performed for osteoarthritis in patients aged 55 or older between January 1st 2002 – December 31st 2016 in Ontario, Canada were identified. Periprosthetic joint infection as the cause for revision surgery was identified with the International Classification of Diseases, 10th Edition (ICD-10), Clinical Modification diagnosis code T84.53 in any component of the healthcare data set. Data were obtained from the Institute for Clinical Evaluative Sciences (ICES). Demographic data and outcomes are summarized using descriptive statistics. We used a Cox proportional hazards model to analyze the effect of surgical factors and patient factors on the risk of developing PJI. Surgical factors include the approach, use of bone graft, use of cement, and the year of surgery. Patient factors include sex, age at surgery, income quintile and rurality (community vs. urban). We compared the 1,2,5 and 10 year PJI rates for patients undergoing THA each year of our cohort with the Cochran-Armitage test. Less than 0.1% of data were missing from all fields except for rurality which was lacking 0.3% of data. A total of 100,674 patients aged 55 or older received a primary total hip arthroplasty for osteoarthritis from 2002–2016. We identified 1034 cases of revision surgery for prosthetic joint infection for an overall PJI rate of 1.03%. When accounting for patients censored at final follow-up, the cumulative incidence for PJI is 1.44%. Our Cox proportional hazards model revealed that male sex, Type II diabetes mellitus, discharge to convalescent care, and having both hips replaced during one's lifetime were associated with increased risk of developing PJI following primary THA. Importantly, the time adjusted risk for PJI was equal for patients operated within the past 5 years, 6–10 years ago, or 11–15 years ago. The surgical approach, use of bone grafting or cement were not associated with increased risk of infection. PJI rates have not changed significantly over the past 15 years. One, two, five and ten-year PJI rates were similar for patients undergoing THA in all qualifying years. Analysis of a population-based cohort of 100,674 patients has shown that the risk of developing PJI following primary THA has not changed over 15 years. The surgical approach, use of bone grafting or cement were not associated with increased risk of infection. Male sex, Type II diabetes Mellitus and discharge to a rehab facility are associated with increased risk of PJI. As the risk of PJI has not changed in 15 years, an appropriately powered trial is warranted to determine interventions that can improve infection rate after THA

The unparalleled events of the year 2020 continue to evolve and challenge the worldwide community on a daily basis. The COVID-19 pandemic has had a major impact on all aspects of our lives, and has caused major morbidity and mortality around the globe. The impact of COVID-19 on the practice of orthopedic surgery has been substantial with practice shutdowns, elective surgery restrictions, heightened utilization of telemedicine platforms and implementation of precautionary measures for in-person clinic visits. During this transition period the scholarly and educational pursuits of academic surgeons have been de-emphasized as the more immediate demands of clinical practice survivorship have been the priority. This unavoidable focus on clinical practice has heightened the importance of orthopedic subspecialty societies in maintaining an appropriate level of attention on research and educational activities. Under the outstanding presidential leadership of Robert Barrack, MD, The Hip Society adapted to the profound challenges of 2020, and maintained strong leadership in the realms of education and research. The recent 2020 summer meeting of the Hip Society was a testimonial to the resilience and dedication of the Society members to ongoing innovation in research and education. Due to travel and social distancing restrictions the 2020 summer meeting was transitioned from an in-person to a virtual meeting format. Dr Barrack and Program Chair Dr John Clohisy assisted with oversight of the meeting, while Olga Foley and Cynthia Garcia ensured the success of the meeting with remarkable planning and organization. These collaborative efforts resulted in an organized, well-attended, high level scientific meeting with engaging discussion and a remarkable virtual conference environment. The Bone & Joint Journal is very pleased to partner with The Hip Society to publish the proceedings of this very unique virtual meeting. The Hip Society is based in the United States and membership is granted to select individuals for leadership accomplishments in education and research related to hip disease. The Society is focused on the mission of advancing the knowledge and treatment of hip disorders to improve the lives of patients. The vision of the Hip Society is to lead in the discovery and dissemination of knowledge related to disorders of the hip. The annual closed meeting is one of the most important events of the society as this gathering highlights timely, controversial and novel research contributions from the membership. The top research papers from The Hip Society meeting will be published and made available to the wider orthopedic community in The Bone & Joint Journal. This partnership with The Bone & Joint Journal enhances the mission and vision of The Hip Society by international dissemination of the meeting proceedings. Given the far-reaching circulation of The Bone & Joint Journal the highest quality work is available to an expanding body of surgeons, associated healthcare providers and patients. Ultimately, this facilitates the overarching Hip Society goal of improving the lives of our patients. The 2020 virtual Hip Society meeting was characterized by outstanding member attendance, high quality paper presentations and robust discussion sessions. The meeting was held over two days and encompassed 58 open paper presentations divided into ten sessions with moderated discussions after each session. All papers will be presented in this issue in abstract form, while selected full papers passing our rigorous peer review process will be available online and in The Bone & Joint Journal in a dedicated supplement in 2021. The first session of the meeting focused on issues related to complex primary THA and osteonecrosis of the femoral head. Dr Gross presented on the conversion of hip fusion to THA in 28 patents at a mean 7 years. He reported a high clinical success rate, yet complications of heterotopic ossification and neurologic injury were relatively common. Consideration of heterotopic ossification prophylaxis and the selective use of a constrained liner were recommended. Dr Pagnano summarized the use of various contemporary porous acetabular components in 38 hips in the setting of prior pelvic radiation. The mean follow-up was 5 years and 10 year survivorship was 100% with all implants radiographically fixed. Dr Bolognesi's study demonstrated that THA in solid organ transplant patients is associated with higher risk for facility placement, transfusions and readmissions. This patient population also has increased mortality risk (4.3% risk at 1 year) especially lung transplant patients. The second group of papers focused on femoral head osteonecrosis. Dr Iorio presented single center data demonstrating that CT scan was a useful adjunct for diagnosis in the staging work-up for cancer, yet was not useful for ARCO staging and treatment decision-making. On the basic science side, Dr Goodman utilized a rabbit model of steroid-induced femoral head osteonecrosis to determine that immunomodulation with IL-4 has the potential to improve bone healing after core decompression. The session was concluded by Dr Nelson's study of ceramic-on-ceramic THA in 108 osteonecrosis patients. The median 12 year results were outstanding with marked increases in PROs, maintenance of high activity levels, and a 3.7% revision rate. In the second session attention was directed to THA instability and spinopelvic mobility. Dr Sierra presented a machine learning algorithm for THA dislocation risk. Two modifiable variables (anterior/lateral approach, elevated liner) were most influential in minimizing dislocation risk. Dr Taunton's study demonstrated a deep learning artificial intelligence model derived from postoperative radiographs to predict THA dislocation risk. High sensitivity and negative predictive value suggest that this model may be helpful in assessing postoperative dislocation risk. In reviewing a large single-center, multiple surgeon cohort of 2,831 DAA procedures, Dr Moskal noted a very low dislocation rate (0.45%) at minimum 2 years. Importantly, spinopelvic pathology or prior spinal instrumentation was not associated with an increased dislocation risk (0.30%). Dr Huo and colleagues analyzed pelvic tilt during functional gait in patients with acetabular dysplasia. They detected variable pelvic tilt on different surfaces with the data suggesting that patients with more anterior pelvic tilt while standing tend to have greater compensatory posterior pelvic tilt during gait. Dr Lamontagne reported on the sagittal and axial spinomobility in patients with hip OA, and highlighted reductions in pelvic tilt, pelvic-femoral-angle, lumbar lordosis and seated maximal trunk rotation when compared to controls. Dr Dennis showed that differences in spinopelvic mobility may explain the variable accuracy of acetabular version measurements on the cross-table lateral radiographs. Dr Gwo-Chin presented on a comprehensive functional analysis of 1,592 patients undergoing THA and observed that spinopelvic abnormalities are not infrequent (14%) in THA patients. Consistent with these findings Dr Murphy and collaborators identified a low prevalence of previous spinal instrumentation (1.5%), yet a high prevalence of spine stiffness (27.6%) in 149 patients undergoing THA. Session three highlighted various aspects of treating hip disease in young patients. Dr Peters investigated the need for subsequent hip arthroscopy in 272 patients treated with an isolated PAO. Only 4.8% of these patients required subsequent arthroscopy calling into question the routine use of combined arthroscopy and PAO. Three papers addressed questions related to THA in young patients. Dr Berend's study of 2532 hips demonstrated that high activity level was not associated with an increased risk of midterm aseptic or all cause failure. Dr Nunley presented on 43 young patients with an average age of 52 years treated with a cementless stem and modular dual mobility articulation. Stress shielding was minimal and no concerning metal ion release detected. Dr Garvin summarized minimum 15 year data of THA with highly cross-linked polyethylene in patient less than 50 years. These hips performed exceptionally well with no mechanical loosening or radiographic osteolysis. Dr Engh examined 10 year results of the Birmingham Hip Resurfacing implant and reported a 92.9 % overall survivorship, with males less than 55 years achieving a 98.3% survivorship. The session was concluded by long-term data on the Conserve Plus hip resurfacing arthroplasty. Dr Amstutz presented an impressive dataset depicting an 83.1% 20 year survivorship for this early resurfacing cohort. Direct anterior approach total hip arthroplasty was the focus of session four. Dr Meneghini reported on the anesthesia and surgical times of direct anterior and posterior approaches from a large healthcare system database. These data suggested longer OR and surgical times for the DAA both in the inpatient and ASC environments. Dr Clohisy introduced the technique and early outcomes of lateral decubitus position DAA. In a learning curve experience of 257 hips. 96% of acetabular components were in the Lewinneck safe zone, the aseptic revision rate was 0.9% and there were no dislocations. Dr Beaule analyzed femoral stem cement mantle with the DAA and posterior approaches by comparing two matched cohorts. Stem alignment and cement mantle quality were equivalent with both approaches. Similarly, Dr Emerson demonstrated technical feasibility and fewer cemented femoral stem failures when compared to cementless stems in a series of 360 DAAs THAs. The final paper of the session presented by Dr Hamilton examined the impact of surgical approach on dislocation after isolated head and liner exchange. Neither the posterior nor the anterior approach was superior in reducing the dislocation rate for these high dislocation risk procedures. The fifth session explored contemporary topics related to anesthesia and pain management. Dr Byrd opened the session with a comparative study evaluating general versus spinal anesthesia for hip arthroscopy. This preliminary study was provoked by the desire to minimize aerosolized exposure early in the COVID-19 pandemic by transitioning to spinal anesthesia. Both anesthetic methods were effective. Dr Austin presented a randomized, double-blind controlled trial comparing spinal anesthetic with mepivacaine, hyperbaric bupivacaine and isobaric bupivacaine. Mepivacaine patients ambulated earlier and were more likely to be discharged the same day. Dr Mont provided a very timely study on the effects of “cannabis use disorder” and THA outcomes. This administrative database study of 44,154 patients revealed this disorder to be associated with longer hospital stays, increased complications rates and higher costs. Dr Bedair investigated whether a highly porous acetabular component submerged in an analgesic solution could enhance perioperative pain management. Interestingly, this novel strategy was associated with a reduction of postoperative pain scores and opioid consumption in 100 experimental patients compared to 100 controls. The concluding paper of the session by Dr Della Valle examined whether decreased discharge opioids led to increased postoperative opioid refills. A large single-center study of 19,428 patients detected a slight increase (5%) in opioid refills but a reduction in total refill morphine milligram equivalents. The final, sixth session of day one considered various challenging aspects of revision hip arthroplasty. Dr Nam started the session with review of preliminary results from a randomized control trial comparing closed incision negative-pressure therapy with a silver-impregnated dressing for wound management in 113 hips undergoing revision arthroplasty. Unlike previous reports, the negative pressure therapy was associated with a higher reoperation rate for wound-related complications. Dr Bostrom highlighted the potential clinical impact of basic biological interventions by establishing the presence of Neutrophil Extracellular Traps (NETS) in fibrotic tissue from human aseptic loosening specimens and in a murine model of unstable tibial implantation. NET inhibition in the murine model prevented the expected tibial implant osseointegration failure. Dr Lombardi presented early 3.3 year clinical results of a highly porous Ti6al4v acetabular component in complex primary and revision arthroplasty. Survivorship for aseptic loosening was 96.6 % and 95.3% for the primary and revision cases, respectively. Dr Schwarzkopf and colleagues explored the impact of time to revision arthroplasty on clinical outcomes. Analysis of 188 revision cases revealed early revisions (less than 2 years from primary) were associated with worse outcomes, longer hospitalizations and higher reoperation rates. Mid-term results for modular dual mobility implants in revision arthroplasty were reviewed by Dr Lachiewicz who reported on 126 hips at a mean 5.5 years. 11% of hips dislocated and the 6 year survival was 91%. An outer head diameter of 48mm or greater was associated with a lower risk of dislocation. Dr Berry concluded the session by discussing the outcomes of treating the challenging problem of interprosthetic femur fractures. A single-center study of 77 cases treated over 32 years demonstrated a 79% success rate free of reoperation at 2 years with 95% of patients being ambulatory. The second day commenced with the seventh session evaluating recent strategies to improve short-term THA outcomes. Dr Bozic and colleagues investigated the association of quality measure public reporting with hip/knee replacement outcomes. Annual trend data from 2010–2011 and 2016–2017 indicate that hospital-level complication and readmission rates decease after the start of public reporting, yet it is difficult to prove a direct effect. Dr Slover reviewed his institutions experience with the Comprehensive Care for Joint Replacement (CJR) model and emphasized that lower CJR target prices make it increasingly difficult for programs to meet target price thresholds. Cost saving strategies including same day discharge and reduction of home health services may result in smaller losses of positive margins. Dr Barsoum reported on the influence of patient and procedure-related risk factors of length of stay after THA. Patient-related risk factors provided substantial predictive value yet procedure-related risk factors (hospital site and surgical approach) remain the main drivers of predicting length of stay. Dr Hozack reviewed an impressive, single surgeon cohort of 3,977 DAA THAs and analyzed adverse events and 90 day perioperative outcomes. Simultaneous bilateral DAA THA was comparable with unilateral or staged bilateral procedures in regards to complications, readmission rate and home discharge rate but with an increased risk of transfusion. To examine the risk of complications with outpatient joint arthroplasty, Dr Della Valle performed a single-surgeon matched cohort analysis comparing outpatient and inpatient hip and knee arthroplasties. Outpatient procedures were not associated with an increased risk of any postoperative complications and actually experienced fewer emergency department visits. The eighth session covered various contemporary challenges in hip arthroplasty care. Dr Griffin began the session with an analysis of the timing of complications associated with two-stage exchange procedures for periprosthetic joint infection (PJI). Of the 189 hips included, 41.6% had a complication and the mortality was 14.1% at 2.5 years, highlighting the morbidity of this treatment method. Dr Fehring provided data assessing the fate of two-stage reimplantation after failed debridement, antibiotics and implant retention (DAIR) for a prosthetic hip infection. This analysis of 114 hips yielded concerning results demonstrating a 42.9% treatment failure of patients treated with a previous DAIR compared to a 12.3% failure rate in patients treated with an initial 2-stage procedure. Dr Jacobs reviewed the analysis of 106 femoral heads with severe corrosion and identified a chemically dominated etching process termed “column damage” to be a detrimental damage mode within CoCr femoral heads that is directly linked to banding within its microstructure. These data indicate that implant alloy microstructure must be optimized to minimize the release of fretting-corrosion products. Simon Mears presented retrospective data from 184 THAs with a dual modular femoral stem. A subgroup of hips with a modular, cobalt chromium femoral neck had a pseudotumor visualized in 15% with only 55% of these having elevated CoCr levels. These findings may support the use of routine follow-up MARS MRI for modular CoCr femoral neck prostheses. The final two studies explored timely issues related to viral illness and hip surgery. Dr Browne analyzed three large administrative databases to elucidate whether patients are at increased risk for viral illnesses following total joint replacement. The incidence of postoperative influenza after total joint replacement was not increased compared to patients not undergoing total joint replacement surgery suggesting that arthroplasty procedures may not heighten the risk of viral illness. In the final paper of the session Dr Haddad presented important data regarding perioperative complications in coronavirus positive patients undergoing surgical treatment of femoral neck fractures. In this multicenter cohort study from the United Kingdom 82 coronavirus positive patients were shown to have longer hospital stays, more critical care unit admissions, higher risk of perioperative complications and an increased mortality compared to 340 coronavirus negative patients. The eighth session had two papers on alternative femoral stem designs and three presentations more focused on femoral fracture treatments. Dr Mihalko focused on the European and US experiences with the Metha femoral neck retaining stem. The US experience mirrored the encouraging results from Europe with a 94% all cause femoral survivorship and a 99.1% femoral aseptic loosening survivorship at 5 years. Dr Kraay summarized dual energy x-ray absorptiometry (DEXA) evaluation of 16 low modulus composite femoral components at long-term follow-up of a mean 22 years. The bone mineral density associated with the implant increased in Gruen zones 2–6 and showed limited decreases in zones 1 and 7. These data support the concept that a low modulus femoral stem may more effectively load the proximal femur. Dr Springer provided data from the American Joint Replacement Registry (AJRR) and by evaluating outcomes of exact matched cohorts of 17,138 patients treated with cementless or cemented femoral implants for femoral neck fractures. Cemented implants were associated with marked reduction in early revision and periprosthetic fractures. However, cemented fixation was associated with an increased mortality at 90 days and 1 year. Additional data from the AJRR was presented by Dr Huddleston who investigated the risk factors for revision surgery after arthroplasty in a cohort of 75,333 femoral neck fractures. THA when compared to hemiarthroplasty was associated with higher early and overall revision rates. Cementless femoral fixation and increased age were also associated with higher rates of any revision. Both of these studies from the AJRR suggest that further consideration should be given to femoral fixation preferences in the femoral neck fracture population. Dr Vail summarized his institution's experience with an interdisciplinary hip fracture protocol for patients undergoing arthroplasty for acute femoral neck fractures. His study compared 157 cases prior to protocol implementation with 114 patients treated after the protocol was established. The impact of the interdisciplinary protocol was impressive as evidenced by a reduced time to operative treatment, length of stay, complication rate and one-year mortality. All being achieved without an increase in readmissions or facility discharges. The final session of the meeting addressed innovations in perioperative care of THA patients. Dr Barrack started the session with an interesting study examining the feasibility and patient preferences regarding telemedicine. A cross-sectional telephone survey of 163 arthroplasty patients indicated that 88% of patients use the internet and 94% own a device capable of videoconferencing. Nevertheless, only 18% of patients preferred a video visit over an in-person clinic visit due to concerns of inferior care. Dr Barnes quantified preoperative optimization work in 100 arthroplasty patients by using EMR activity logs and determined the surgical team spends an average 75 minutes per case on preoperative work activities. Dr Duwelius reported the early outcomes of primary THA with a smartphone-based exercise and educational platform compared to standard of care controls. A randomized control trial design with 365 patients demonstrated similar outcomes and non-inferiority of the smartphone platform relative to complications, readmissions, emergency room/urgent care visits. The association of controlled substance use with THA outcomes was assessed by Dr Higuera Rueda. A quantitative assessment using the NarxCare score identified 300 and above as a score associated with adverse outcomes after THA. Dr Macaulay reviewed data from a large retrospective study of 1,825 THAs indicating that discontinuation of intermittent pneumatic compression devices does not increase the risk of venous thromboembolism in standard risk patients being treated with 81mg ASA BID as prophylaxis. Dr Antoniou presented the final paper of the meeting investigating potential changes in patient health status as an indication for surgery over time. Data from this large systematic review of the literature found patients undergoing THA at similar health status to the past with no influence form patient age, gender, year of enrollment or geographic region. As summarized above, the 2020 virtual Hip Society Summer Meeting was rich in scientific content, productive discussion and a collaborative spirit. This collective body of work will result in impactful scientific contributions and will serve as a foundation for future innovation and advancements in the treatment of hip disease

Introduction. Previous registry studies of ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) have focused on revision outcomes following primary surgery. Less is known about the effect of ceramic bearings on infection, dislocation, and mortality as outcomes following primary total hip arthroplasty (THA) for the Medicare population. We asked (1) does the use of C-PE bearings influence outcomes following THA as compared with metal-on-polyethylene (M-PE); and (2) does the use of COC bearings influence outcomes following THA as compared with M-PE?. Methods. A total of 315,784 elderly Medicare patients (65+) who underwent primary THA between 2005 and 2014 with known bearing types were identified from the Medicare 100% inpatient sample administrative database. Outcomes of interest included relative risk of 90-day readmission, infection, dislocation, revision, or mortality at any time point after primary surgery. Propensity scores were developed to adjust for selection bias in the choice of bearing type at index primary surgery. Cox regression incorporating propensity score stratification (10 levels) was then used to evaluate the impact of bearing surface selection on outcomes, after adjusting for patient-, hospital-, and surgeon-related factors. Results. For primary THA patients treated with C-PE bearings and COC bearings, there was significantly reduced risk of infection relative to M-PE bearings (C-PE Hazard Ratio, HR: 0.86, p=0.001; COC Hazard Ratio, HR: 0.74, p=0.01). For the C-PE cohort, we also observed reduced risk of 90-day readmission (HR: 0.94, p<0.001); dislocation (HR: 0.81, p<0.001); and mortality (HR: 0.92, p<0.001). There was no significant difference in risk of revision for either the C-PE or COC bearing cohorts when compared with M-PE. For the COC cohort, there was no significant difference in readmission, dislocation, or mortality risk. Conclusions. The results indicate that, after adjusting for selection bias and various confounding patient-, surgeon-, and hospital-related factors, Medicare patients treated with primary THA with ceramic bearings exhibit lower risk of infection than those treated with M-PE bearings. In addition, C-PE bearings were associated with lower risk of dislocation and mortality. As in previous registry studies, we found that ceramic bearings have similar revision risk as M-PE bearings in primary THA at between 8 and 9 years of follow-up. The findings of this study support further research into the long-term association between ceramic bearings in primary THA and clinical outcomes

Over the last decade, there has been a growing body of level I evidence supporting non-operative management (focused on early range of motion and weight bearing) of acute Achilles tendon ruptures. Despite this emerging evidence, there have been very few studies evaluating its uptake. Our primary objective was to determine whether the findings from a landmark Canadian trial assessing the optimal management strategy for acute Achilles tendon ruptures influenced the practice patterns of orthopaedic surgeons in Ontario, Canada over a 12-year time period. As a second objective we examined whether patient and provider predictors of surgical repair utilisation differed before and after dissemination of the landmark trial results. Using provincial health administrative databases, we identified Ontario residents 18 years of age and older with an acute Achilles tendon rupture from April 2002 to March 2014. The proportion of surgically repaired ruptures was calculated for each calendar quarter and year. A time-series analysis using an interventional autoregressive integrated moving average (ARIMA) model was used to determine whether changes in the proportion of surgically repaired ruptures were chronologically related to the dissemination of results from a landmark Canadian trial by Willits et al. (first quarter, 2009). Spline regression was then used to independently identify critical time-points of change in the surgical repair rate to confirm our findings. A multivariate logistic regression model was used to assess for differences in patient and provider predictors of surgical repair utilisation before and after the landmark trial. From the second quarter of 2002 to the first quarter of 2010 the surgical repair rate remained constant at ∼21%, however, by the first quarter of 2014 it fell to 6.5%. A statistically significant decrease in the rate of surgical repair (P<0.001) was observed after the results from a landmark Canadian trial were presented at a major North American conference (February 2009). Both teaching and non-teaching hospitals demonstrated a decline in the surgical repair rate over the study period, however, only the decrease seen at non-teaching hospitals was found to be significantly associated with the dissemination of landmark trial results (P<0.001). All other predictors of surgical repair utilisation remained unchanged in the before-and-after analysis with the exception of patients 30 years of age and younger having a higher odds of undergoing surgical repair after the trial when compared to those 51 years of age and older. The current study demonstrates that large, well-designed randomised trials, such as the one conducted by Willits et al. can significantly change the practice patterns of orthopaedic surgeons. Moreover, the decline in surgical repair rate observed at both teaching and non-teaching hospitals suggests both academic and non-academic surgeons readily incorporate high quality evidence in to their practice

Introduction. Previous studies of ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) hip bearings have focused on outcomes following primary surgery. Less is known about the utilization or outcomes of ceramic bearings in revision total hip arthroplasty (R-THA) for the Medicare population in the US. We asked (1) what is the utilization of ceramic bearings for R-THA in the Medicare population and how has it evolved over time; (2) does the use of C-PE bearings influence outcomes following R-THA as compared with metal-on-polyethylene (M-PE); and (3) does the use of COC bearings influence outcomes following R-THA as compared with M-PE?. Methods. A total of 31,809 Medicare patients (aged > 65y) who underwent R-THA between 2005 and 2013 with known bearing types were identified from the Medicare 100% inpatient sample administrative database. Outcomes of interest included relative risk of readmission (90 days) or infection, dislocation, rerevision, or mortality at any time point after revision. Propensity scores were developed to adjust for selection bias in the choice of bearing type at revision surgery. Cox regression incorporating propensity score stratification (10 levels) was then used to evaluate the impact of bearing surface selection on outcomes, after adjusting for patient-, hospital-, and surgeon-related factors. Results. The utilization of C-PE and COC bearings in RHA increased from 5.3% to 26.6% and from 1.8% to 2.5% between 2005 and 2013, respectively. For R-THA patients treated with C-PE bearings, there was reduced risk of 90-day readmission (Hazard Ratio, HR: 0.90, 95% CI: 0.84–0.96, p=0.007). We also observed a trend for reduced risk of infection with C-PE (HR: 0.88, 95% CI: 0.74–1.04) that did not reach statistical significance (p = 0.14). For R-THA patients treated with COC, there was reduced risk of dislocation (Hazard Ratio, HR: 0.76, 95% CI: 0.58–0.99, p=0.04). There was no significant difference in risk of rerevision or mortality for either the C-PE or COC bearing cohorts when compared with M-PE. Discussion. The results indicate that, after adjusting for selection bias and various confounding patient-, surgeon-, and hospital-related factors, Medicare patients treated in a revision scenario with ceramic bearings exhibit similar risk of rerevision, infection, or mortality as those treated with M-PE bearings. Conversely, we found an association between the use of specific ceramic bearings in R-THA and reduced risk of readmission (C-PE) and dislocation (COC). The findings of this study support further research into the association between ceramic bearings in R-THA and lower risk of hospital readmission, dislocation, and, potentially, infection

Background. The most appropriate form of chemical thromboprophylaxis following knee replacement is a contentious issue. Most national guidelines recommend the use of low molecular weight Heparin (LMWH) whilst opposing the use of aspirin. We compared thromboembolic events, major haemorrhage and death after knee replacement in patients receiving either aspirin or LMWH. Methods. Data from the National Joint Registry for England and Wales was linked to an administrative database of hospital admissions in the English National Health Service. A total of 156 798 patients undergoing knee replacement between April 2003 and September 2008 were included and followed up for 90 days. Multivariable risk modelling was used to estimate odds ratios adjusted for baseline risk factors (AOR). An AOR < 1 indicates that risk rates are lower with LMWH than with aspirin. Results. In all, 23.1% of patients were prescribed aspirin and 76.9% LMWH. We found no statistically significant differences in the rate of pulmonary embolism (aspirin 0.49%, LMWH 0.45%, AOR 0.88; 95% confidence intervals (CI) 0.74 to 1.05), 90-day mortality (0.39% versus 0.45%, AOR 1.13; 95% CI 0.94–1.37) and major haemorrhage (0.37% versus 0.39%, AOR 1.01; 95% CI 0.83–1.22). There was a significantly greater likelihood of requirement for return to theatre in the aspirin group (0.26% versus 0.19%, AOR 0.73; 95% CI 0.58–0.94). Discussion. Between patients receiving LMWH or aspirin, there was no difference in the risk of pulmonary embolus, 90-day mortality and major haemorrhage. These results should be considered when the existing guidelines for thromboprophylaxis after knee replacement are reviewed

The purpose of this population-based study was to determine the association between morbid obesity and 10-year mortality and complications in patients undergoing primary THA. A cohort study of 22,251 patients, aged 45–74 years old, treated with primary THA between 2002 and 2007 for osteoarthritis, was conducted using Ontario administrative healthcare databases. Patients were followed for 10 years. Risk ratios (RRs) of mortality, reoperation, revision, and dislocation in patients with body mass index (BMI) > 45 kg/m2(morbidly obese patients) compared with BMI ≤45 kg/m2 (non-morbidly obese) were estimated. 3.3% of the cohort (726) was morbidly obese. Morbidly obese patients were younger (mean age 60.6 vs. 63.3, P-value < 0 .001) and more likely to be female (63.9% vs. 52.2%, P-value < 0 .001), compared with non-morbidly obese patients. Morbid obesity was associated with higher 10-year risk of death (RR 1.38, 95% CI 1.18, 1.62). Risks of revision (RR 1.43, 95% CI 0.96, 2.13) and dislocation (RR 2.38, 95% CI 1.38, 4.10) were higher in morbidly obese men, compared with non-morbidly obese men, there were no associations between obesity and revision or dislocation in women. Risk of reoperation was higher in morbidly obese women, compared to non-morbidly obese women (RR 1.60, 95% CI 1.05, 2.40), there was no association between obesity and reoperation in men. Morbidly obese patients undergoing primary THA are at higher risks of long-term mortality and complications. There were differences in complication risk by sex. Results should inform evidence-based perioperative counseling of morbidly obese patients considering THA