Over the Past Decade, Preoperative Anemia Has Become a Greater Predictor of Transfusions After Total Knee Arthroplasty.

BACKGROUND: With advancements in perioperative blood management and the use of tranexamic acid, the rate of transfusions after total knee arthroplasty (TKA) has substantially decreased. As these principles are refined, other modifiable risk factors, such as preoperative anemia, may play an increasingly important role in transfusion risk for patients undergoing TKA. METHODS: A multicenter, national database was utilized to identify patients undergoing TKA from 2010 to 2021. Anemia was defined by World Health Organization definitions as < 12 g/dL for women and < 13 g/dL for men. A predictive model was created using backwards elimination logistic regression to predict transfusion risk, controlling for demographic and medical covariates. The coefficient of anemia was then analyzed for each year. The trend over time was fitted with a best-fit linear regression equation. RESULTS: There were 509,117 patients who underwent TKA, and had a mean age of 67 years (range, 18 to 89). There were 57,716 (11%) patients who were anemic preoperatively, and 15,426 (3%) of patients required a transfusion. Rate of transfusion decreased from 10.6% in 2010 to 0.6% in 2021. The odds ratio associated with anemia as a predictor of transfusion increased from 3.1 (95% confidence interval: 2.1 to 4.6) in 2010 to 14.0 (95% confidence interval: 8.9 to 24) in 2021. CONCLUSIONS: The results of this study demonstrate that the importance of preoperative anemia as a predictor of transfusion has increased over the past decade as rates of transfusion have decreased. As perioperative blood management protocols improve, preoperative anemia should be considered an important focus of intervention to reduce the risk of transfusion prior to TKA. LEVEL OF EVIDENCE: III.

Preoperative weight loss before total hip arthroplasty negatively impacts postoperative outcomes.

BACKGROUND: Obesity adversely impacts outcomes of total hip arthroplasty (THA), leading surgeons to impose body mass index cutoffs for patient eligibility and encourage preoperative weight loss. This study aimed to determine if preoperative weight loss impacts outcomes of THA in the general patient population and if it mitigates poor outcomes in obese patients. METHODS: Patients who underwent THA from 2013-2020 were identified in the National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified by weight loss of >10% of body weight over the preceding 6 months. We used multivariable linear and logistic regression models, adjusted for age, sex, race/ethnicity, and comorbidities, to examine the effect of significant preoperative weight loss on 30-day outcomes after THA in the general and obese patient populations. RESULTS: In the overall population, patients who lost significant weight preoperatively had significantly increased length of stay, were more likely to have a non-home discharge, return to the operating room, or be readmitted, and were more likely to experience numerous medical complications. In the obese population, patients who lost significant weight preoperatively had significantly increased length of stay and were more likely to require a transfusion or experience any medical complication. DISCUSSION: Rapid significant preoperative weight loss is not associated with improved postoperative outcomes after THA in the obese population and is associated with worse outcomes in the general population. Arthroplasty surgeons should balance these risks with the risks of obesity when advising patients about preoperative weight loss prior to THA. LEVEL OF EVIDENCE: III.

Cementless Total Knee Arthroplasty: A Resurgence-Who, When, Where, and How?

BACKGROUND: Total knee arthroplasty (TKA) is one of the most common procedures in orthopaedics, but there is still debate over the optimal fixation method for long-term durability: cement versus cementless bone ingrowth. Recent improvements in implant materials and technology have offered the possibility of cementless TKA to change clinical practice with durable, stable biological fixation of the implants, improved operative efficiency, and optimal long-term results, particularly in younger and more active patients. METHODS: This symposium evaluated the history of cementless TKA, the recent resurgence, and appropriate patient selection, as well as the historical and modern-generation outcomes of each implant (tibia, femur, and patella). Additionally, surgical technique pearls to assist in reliable, reproducible outcomes were detailed. RESULTS: Historically, cemented fixation has been the gold standard for TKA. However, cementless fixation is increasing in prevalence in the United States and globally, with equivalent or improved results demonstrated in appropriately selected patients. CONCLUSIONS: Cementless TKA provides durable biologic fixation and successful long-term results with improved operating room efficiency. Cementless TKA may be broadly utilized in appropriately selected patients, with intraoperative care taken to perform meticulous bone cuts to promote appropriate bony contact and biologic fixation.

Can You Pay Your Way to Readership? Free to Publish Open Access Formats Receive Greater Readership and Citations Than Paid Open Access Formats in Total Knee Arthroplasty Literature.

BACKGROUND: As publishing with open access is becoming increasingly popular within orthopaedics, understanding the types of publishing options available and what each may deliver is critically important. Hybrid articles require a high article processing charge. Open journal articles have a lower fee, while closed license articles are freely accessible at no charge. Open repository articles are peer-reviewed manuscripts posted freely online. The purpose of this study was to determine the relationship between article type and resulting citations, social media attention, and readership in total knee arthroplasty (TKA) literature. METHODS: Open access TKA journal articles published since 2016 were found using the Altmetric Explorer Database. Data gathered included the Altmetric Attention Score (attention), Mendeley Readership Score (readership), and citations per article. Articles were grouped by type: open journal, hybrid, closed license, and open repository. Results were analyzed using descriptive statistics and Tukey's analysis; α = 0.05. RESULTS: A total of 9,606 publications were included. The open repository had the greatest mean citations (14.40), while open journal (9.55) had fewer than all other categories (P < .001). Hybrid had the greatest mean attention (10.35), and open journal (6.16) had a lower mean attention than all other categories (P ≤ .002). Open repository had the greatest mean readership (44.68), and open journal (34.00) had a lower mean readership than all other categories (P ≤ .012). The mean publication fee for paid publication options was $1,792 United States dollars. CONCLUSIONS: In open access TKA literature, free-to-publish open repositories had the greatest mean citations and readership. Free publication options, open repositories and closed licenses, had greater readership compared to paid publication options.

The Definition of Anemia Matters When Using Preoperative Hemoglobin as a Screening Tool Prior to Total Hip and Knee Arthroplasty.

BACKGROUND: Preoperative anemia is common in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). Several definitions of anemia have been described, with no clear consensus on the optimal one for preoperative screening. We hypothesized that depending on the definition used preoperatively, the proportion of anemic patients identified who would require a postoperative allogeneic blood transfusion would vary significantly. METHODS: A total of 681,141 patients were identified in a national database who underwent either THA or TKA. Preoperative anemia was classified according to the World Health Organization (WHO) definition, Cleveland Clinic (CC) definition, or race, age, and sex-specific definition described by Beutler et al in 2006. The optimal preoperative (OP) hemoglobin thresholds to predict perioperative transfusions were also calculated using receiver operating characteristic curves. RESULTS: When using the WHO definition, 18% of anemic patients required a transfusion versus 14% (OP definition), 12% (CC definition), and 16% (Beutler definition). Similarly, 0.69% of anemic patients sustained a periprosthetic joint infection within 30 days using the WHO definition versus 0.59% (OP definition), 0.60% (CC definition), or 0.66% (Beutler definition). Using the WHO definition, 5.3% of patients would have sustained a major complication versus 4.5% (OP definition), 4.4% (CC definition), and 5.0% (Beutler definition). CONCLUSIONS: Variation in the definition of anemia for preoperative screening in THA and TKA results in substantial differences in discriminative ability to predict perioperative transfusions. The WHO definition identified the largest proportion of patients who ultimately received a perioperative transfusion.

Open Access Publication in Total Knee Arthroplasty Is Associated With Increased Social Media Attention, but Is Not Associated With Increased Citations.

BACKGROUND: Open access (OA) publication is growing in total joint arthroplasty literature. While OA manuscripts are free to view, these publications require a fee from authors. This study aimed to compare social media attention and citation rates between OA and non-OA publications in the total knee arthroplasty (TKA) literature. METHODS: There were 9,606 publications included, with 4,669 (48.61%) as OA articles. The TKA articles were identified from 2016 to 2022. Articles were grouped as OA or non-OA and Altmetric Attention Score (AAS), a weighted count of social media attention, and the Mendeley readership were analyzed using negative binomial regressions while adjusting for days since publication. RESULTS: The OA articles had greater mean AAS (13.45 versus 8.42, P = .012) and Mendeley readership (43.91 versus 36.72, P < .001). OA was not an independent predictor of number of citations when compared to non-OA articles (13.98 versus 13.63, P = .914). Subgroup analysis of studies in the top 10 arthroplasty journals showed OA was not an independent predictor of AAS (13.51 versus 9.53, P = .084) or number of citations (19.51 versus 18.74, P = .495) but was an independent predictor of Mendeley readership (49.05 versus 40.25, P < .003). CONCLUSION: The OA publications in the TKA literature were associated with increased social media attention, but not overall citations. This association was not observed among the top 10 journals. Authors may use these results to weigh the relative importance of readership, citations, and online engagement to the cost of OA publication.

Publishing on Topical Subjects in Total Joint Arthroplasty Is Associated With Increased Social Media Attention.

BACKGROUND: Social media platforms are often used for research dissemination and collaboration. Given the increased prevalence of online-only publications, understanding what drives research dissemination is important. Here, we analyzed factors associated with increased social media attention among peer-reviewed publications in total knee arthroplasty, total hip arthroplasty, and unicompartmental knee arthroplasty. METHODS: We analyzed publications about total knee arthroplasty, total hip arthroplasty, or unicompartmental knee arthroplasty from 2010 to 2022 using a national database. We analyzed a weighted count of social media mentions, using negative binomial regressions adjusting for days since publication. Publications on "hot topics" in arthroplasty were examined including navigation/robotics, COVID-19, race/ethnicity, body mass index, and reimbursement. There were 9,542 publications included, 4,216 (44%) were open access (OA), 338 (3.5%) included navigation, 32 (0.34%) discussed race/ethnicity, 20 (0.2%) discussed COVID-19, 3,840 (40%) were randomized studies, 30 (0.3%) discussed reimbursement, and 2,867 (30%) were in top-10 orthopaedic journals. RESULTS: Factors associated with higher weighted score included studies about COVID-19 (50 versus 6.0, P < .001), race/ethnicity (15.8 versus 6.0, P < .001), OA status (6.3 versus 5.8, P = .001), and randomized studies (6.5 versus 5.7, P < .001). Studies from top-10 journals had a lower score (5.8 versus 6.2, P = .025), as did studies about body mass index (3.4 versus 6.1, P = .001). Studies about navigation and reimbursement did not have significantly different scores. CONCLUSIONS: Studies on COVID-19, race/ethnicity, randomized studies, and OA publication were associated with increased social media while those in top-10 orthopaedic journals had lower scores. LEVEL OF EVIDENCE: Level IV, Prognostic Study.

Preoperative COVID-19 infection status negatively impacts postoperative outcomes of geriatric hip fracture surgery.

OBJECTIVES: Compare outcomes for patients with recently diagnosed COVID-19 infection to those without COVID-19 infection undergoing operative treatment of hip fractures using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. DESIGN: Retrospective propensity score matched cohort. METHODS: Patients who received surgery for an acute hip fracture (intramedullary nail (IMN), open reduction internal fixation (ORIF) or hemiarthroplasty) in 2021 were identified from the NSQIP database. Propensity score matching was implemented using patient demographics and preoperative medical conditions to compare outcomes for COVID-19-positive and COVID-19-negative cohorts. RESULTS: After matching, COVID-19-positive patients exhibited a higher risk of 30-day mortality (Odds ratio (OR) 1.48, 95 % confidence interval (CI) 1.01 - 2.04), pneumonia (OR 2.90, 95 % CI: 1.91 - 4.33), unplanned intubation (OR 2.53, 95 % CI: 1.39 - 4.39), and septic shock (OR 2.51, 95 % CI: 1.10 - 4.67). COVID-19-positive patients were also more likely to have a longer length of hospital stay (Hazard Ratio 1.3, 95 % CI: 1.20 - 1.41) and were more likely to be discharged to an acute care hospital (OR 1.90, 95 % CI: 1.03 - 3.06). CONCLUSIONS: Active COVID-19 infection is an independent risk factor for complications as well as increased resource utilization in patients undergoing surgical treatment of acute hip fracture. Using the results of this multicenter study, quantification of these risks can help inform practice and treatment protocols for this population. LEVEL OF EVIDENCE: III.

Mapping the course to recovery: a prospective study on the anatomic distribution of early postoperative pain after total knee arthroplasty.

INTRODUCTION: Early postoperative pain following total knee arthroplasty significantly impacts outcomes and patient satisfaction. However, the characteristics and sources of early pain after total knee arthroplasty remain unclear. Therefore, the purpose of this study was to determine the anatomic distribution and course of postoperative pain in the acute and subacute period following total knee arthroplasty. METHODS: A prospective observational study of primary, elective unilateral total knee arthroplasty cases was conducted at our academic tertiary care medical center from January 2021 to September 2021. Preoperative variables were extracted from institutional electronic medical records. Postoperatively, patients utilized a knee pain map to identify the two locations with the most significant pain and rated it using the visual analog scale (VAS). The data were collected on day 0, at 2 weeks, 2 months, and 6 months after operation. RESULTS: This study included 112 patients, with 6% of patients having no pain at postoperative day 0, 22% at 2 weeks, 46% at 2 months, and 86% at 6 months after operation. In those who reported pain, the VAS score (mean ± standard deviation) was 5.8 ± 2.4 on postoperative day 0 and decreased at each follow-up time point (5.4 ± 2.3 at 2 weeks, 3.9 ± 2.2 at 2 months, and 3.8 ± 2.7 at 6 months). The majority of patients were able to identify distinct loci of pain. The most common early pain loci were patellae, thigh, and medial joint line, and this distribution dissipated by 6 months. CONCLUSION: At 2 postoperative weeks, pain was primarily at the medial joint, and at 6 months postoperatively, pain was more likely to be at the lateral joint. No relationship was found between pain at six months and pain scores or location at postoperative day 0 or 2 weeks. Understanding the distribution and progression of knee pain following total knee arthroplasty may benefit patient education and targeted interventions. LEVEL OF EVIDENCE: Level II, prospective observational study.

Ultracongruent Designs Compared to Posterior-Stabilized and Cruciate-Retaining Tibial Inserts - What Does the Evidence Tell Us? A Systematic Review and Meta-Analysis.

BACKGROUND: Posterior-stabilized (PS) and cruciate-retaining (CR) have been the most common tibial designs used in total knee arthroplasty. Ultra-congruent (UC) inserts are becoming popular because they preserve bone without relying on the posterior cruciate ligament balance and integrity. Despite increasing use, there is no consensus on how UC inserts perform versus PS and CR designs. METHODS: A comprehensive literature search of 5 online databases was performed for articles from January 2000 to July 2022 comparing the kinematic and clinical outcomes of PS or CR tibial inserts to UC inserts. There were nineteen studies included. There were 5 studies comparing UC to CR and 14 comparing UC to PS. Only one randomized controlled trial (RCT) was rated "good quality". RESULTS: For CR studies, pooled analyses showed no difference in knee flexion (n = 3, P = .33) or Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (n = 2, P = .58). For PS studies, meta-analyses showed better anteroposterior stability (n = 4, P < .001) and more femoral rollback (n = 2, P < .001) for PS but no difference in knee flexion (n = 9, P = .55) or medio-lateral stability (n = 2, P = .50). There was no difference with WOMAC (n = 5, P = .26), Knee Society Score (n = 3, P = .58), Knee Society Knee Score (n = 4, P = .76), or Knee Society Function Score (n = 5, P = .51). CONCLUSION: Available data demonstrates there are no clinical differences between CR or PS and UC inserts in small short-term studies ending around 2 years after surgery. More importantly, high-quality research comparing all inserts is lacking, demonstrating a need for more uniform and longer-term studies beyond 5 years after surgery to justify increased UC usage.

Body Mass Index and Revision Total Knee Arthroplasty: Does Cause for Revision Vary by Underweight or Obese Status?

BACKGROUND: Body mass index (BMI) impacts risk for revision total knee arthroplasty (rTKA), but the relationship between BMI and cause for revision remains unclear. We hypothesized that patients in different BMI classes would have disparate risk for causes of rTKA. METHODS: There were 171,856 patients who underwent rTKA from 2006 to 2020 from a national database. Patients were classified as underweight (BMI < 19), normal-weight, overweight/obese (BMI 25 to 39.9), or morbidly obese (BMI > 40). Multivariable logistic regressions adjusted for age, sex, race/ethnicity, socioeconomic status, payer status, hospital geographic setting, and comorbidities were used to examine the effect of BMI on risk for different rTKA causes. RESULTS: Compared to normal-weight controls, underweight patients were 62% less likely to undergo revision due to aseptic loosening, 40% less likely due to mechanical complications, 187% more likely due to periprosthetic fracture, 135% more likely due to periprosthetic joint infection (PJI). Overweight/obese patients were 25% more likely to undergo revision due to aseptic loosening, 9% more likely due to mechanical complications, 17% less likely due to periprosthetic fracture, and 24% less likely due to PJI. Morbidly obese patients were 20% more likely to undergo revision due to aseptic loosening, 5% more likely due to mechanical complications, and 6% less likely due to PJI. CONCLUSION: Mechanical reasons were more likely to be the cause of rTKA in overweight/obese and morbidly obese patients, compared to underweight patients, for whom revision was more likely to be infection or fracture related. Increased awareness of these differences may promote patient-specific management to reduce complications. LEVEL OF EVIDENCE: III.

A Surgical Robotic System for Osteoporotic Hip Augmentation: System Development and Experimental Evaluation.

Minimally-invasive Osteoporotic Hip Augmentation (OHA) by injecting bone cement is a potential treatment option to reduce the risk of hip fracture. This treatment can significantly benefit from computer-assisted planning and execution system to optimize the pattern of cement injection. We present a novel robotic system for the execution of OHA that consists of a 6-DOF robotic arm and integrated drilling and injection component. The minimally-invasive procedure is performed by registering the robot and preoperative images to the surgical scene using multiview image-based 2D/3D registration with no external fiducial attached to the body. The performance of the system is evaluated through experimental sawbone studies as well as cadaveric experiments with intact soft tissues. In the cadaver experiments, distance errors of 3.28mm and 2.64mm for entry and target points and orientation error of 2.30° are calculated. Moreover, the mean surface distance error of 2.13mm with translational error of 4.47mm is reported between injected and planned cement profiles. The experimental results demonstrate the first application of the proposed Robot-Assisted combined Drilling and Injection System (RADIS), incorporating biomechanical planning and intraoperative fiducial-less 2D/3D registration on human cadavers with intact soft tissues.

Racial Disparities in Short-Stay and Outpatient Total Hip and Knee Arthroplasty: 13-year Trend in Utilization Rates and Perioperative Morbidity Using a National Database.

BACKGROUND: The objective of this study was to assess racial and ethnic disparities in short-stay (< 2-midnight length of stay) and outpatient (same-day discharge) total joint arthroplasties (TJAs). We aimed to determine (1) whether there are differences in postoperative outcomes between short-stay Black, Hispanic, and White patients and (2) the trend in utilization rates of short-stay and outpatient TJA across these racial groups. METHODS: This was a retrospective cohort study of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). Short-stay TJAs done between 2008 and 2020 were identified. Patient demographics, comorbidities, and 30-day postoperative outcomes were assessed. Multivariate regression analysis was used to assess differences between racial groups in minor and major complication rates, as well as readmission and revision surgery rates. RESULTS: Of a total of 191,315 patients, 88% were White, 8.3% were Black, and 3.9% were Hispanic. Minority patients were younger and had greater comorbidity burden when compared with Whites. Black patients had greater rates of transfusions and wound dehiscence when compared with White and Hispanic patients ( P < 0.001, P = 0.019, respectively). Black patients had lower adjusted odds of minor complications (odds ratio [OR], 0.87; confidence interval [CI], 0.78 to 0.98), and minorities had lower revision surgery rates in comparison with Whites (OR, 0.70; CI, 0.53 to 0.92, and OR, 0.84; CI, 0.71 to 0.99, respectively). The utilization rate for short-stay TJA was most pronounced for Whites. CONCLUSION: There continues to persist marked racial disparities in demographic characteristics and comorbidity burden in minority patients undergoing short-stay and outpatient TJA procedures. As outpatient-based TJA becomes more routine, opportunities to address these racial disparities will become increasingly more important to optimize social determinants of health. LEVEL OF EVIDENCE: III, retrospective cohort study.

Risk factors for pain after total hip arthroplasty: a systematic review.

BACKGROUND: Approximately 23% of patients develop hip pain after total hip arthroplasty (THA). In this systematic review, we aimed to identify risk factors associated with postoperative pain after THA to optimize preoperative surgical planning. METHODS: Six literature databases were searched for articles published from January 1995 to August 2020. Controlled trials and observational studies that reported measurements of postoperative pain with assessments of preoperative modifiable and non-modifiable risk factors were included. Three researchers performed a literature review independently. RESULTS: Fifty-four studies were included in the study for analysis. The most consistent association between worse pain outcomes and the female sex is poor preoperative pain or function, and more severe medical or psychiatric comorbidities. The correlation was less strong between worse pain outcomes and preoperative high body mass index value, low radiographic grade arthritis, and low socioeconomic status. A weak correlation was found between age and worse pain outcomes. CONCLUSIONS: Preoperative risk factors that were consistently predictive of greater/server postoperative pain after THA were identified, despite the varying quality of studies that prohibited the arrival of concrete conclusions. Modifiable factors should be optimized preoperatively, whereas non-modifiable factors may be valuable to patient education, shared decision-making, and individualized pain management.

Residency Match Rates in Orthopaedic Surgery Based on Sex, Under-Represented in Medicine Status, and Degree Type.

Orthopaedic surgery is well recognized as one of the most competitive and least diverse medical specialties. Despite efforts toward improving diversity, studies have shown that gender and racial/ethnic disparities continue to persist in orthopaedic graduate medical education. Therefore, we sought to identify the match rates of traditionally under-represented groups within orthopaedic surgery-female candidates, racial and ethnic minorities under-represented in medicine (URiM), and osteopathic physicians-compared with their application rates. Methods: A retrospective review of the Electronic Residency Application Service (ERAS) application data from the 2017 to 2021 application cycles was performed, and the total number of applicants, sex, race/ethnicity, and degree type of all students applying for orthopaedic surgery were recorded. A separate database, the Orthopaedic Residency Information Network (ORIN), which is a database self-reported by residency programs to provide information to applicants, was also queried to identify the total number of residents, sex, race/ethnicity, and degree type of all current residents in June 2022, corresponding to those residents who matched in 2017 to 2021. Results: From the ERAS application data, a total of 7,903 applicants applied to orthopaedic surgery during the study period. A total of 1,448 applicants (18%) were female, 1,307 (18%) were URiM, and 1,022 (15%) were from an osteopathic medical school. Based on the ORIN database, 688 of 3,574 residents (19%) were female, 1,131 of 7,374 (19%) were URiM, and 1,022 of US medical school graduates (12%) had a DO degree. The application and match rates were not significantly different for female (p = 0.249) and URiM (0.187) applicants; however, there was a significant difference in the application and match rates (15% vs 12%; p = 0.035) for US medical graduates with a DO degree. Conclusion: In recent years, there has been a significant and necessary push to increase diversity in the field of orthopaedic surgery. From 2017 to 2021, match rates of female and URiM candidates are reflective of their application rates. Osteopathic applicants in orthopaedic surgery have a lower match rate than their allopathic counterparts. Level of Evidence: III.

Preoperative Anemia is an Independent Risk Factor for Increased Complications and Mortalities After Total Knee Arthroplasty Regardless of Postoperative Transfusions.

BACKGROUND: Preoperative anemia is associated with adverse events following total knee arthroplasty (TKA). It remains unknown if this effect is due to comorbid conditions, adverse events associated with transfusions, or the anemia itself. We used propensity-score matching to isolate the effect of anemia on postoperative complications following TKA, regardless of blood transfusions. METHODS: Patients undergoing primary TKA from 2010 to 2020 without receiving a perioperative blood transfusion, were identified using a large national database. A 1:1 propensity score matching was used to create cohorts of anemic and nonanemic patients matched on Charlson Comorbidity Index (CCI), American Society of Anesthesiology (ASA) classification, age, sex, and prevalence of bleeding disorders. There were 43,370 patients were included in each group (mean age 68 [range, 29 to 99; 44% male]). The 1:1 matching yielded groups with similar CCI, ASA classification, age, sex, and prevalence of bleeding disorders (all, P > .9). RESULTS: Anemic patients had a higher incidence of major complications (4.1 versus 2.8%; P < .001), 30-day mortality rate (0.2 versus 0.1%; P < .001), and extended lengths of stay (LOS) (8.3 versus 6.6%; P < .001). Anemic patients also had increased 30-day rates of wound infection requiring hospital admission, renal failure, reintubation, myocardial infarction, and pneumonia (all, P < .001). CONCLUSION: In matched cohorts of anemic versus nonanemic patients undergoing TKA, all who had no postoperative blood transfusion, anemic patients had higher rates of complications, extended LOS, and mortalities. Thus, anemia should be considered an independent risk factor for complications following TKA.

Determining a preoperative international normalised ratio threshold safe for hip fracture surgery.

INTRODUCTION: The purpose of this study was first, to assess the relationship between preoperative INR (international normalised ratio) and postoperative complication rates in patients with a hip fracture, and second, to establish a threshold for INR below which the risk of complications is comparable to those in patients with a normal INR. METHODS: We retrospectively reviewed the American College of Surgeons National Surgical Quality Improvement Program and found 35,910 cases who had undergone surgery for a hip fracture between 2012 and 2018. Cases were stratified into 4 groups based on their preoperative INR levels: <1.4; ⩾1.4 and <1.6; ⩾1.6 and <1.8 and ⩾1.8. These cohorts were assessed for differences in preoperative factors, intraoperative factors, and postoperative course. Multivariate logistic regression was used to assess the risk of transfusion, 30-day mortality, cardiac complications, and wound complications adjusting for all preoperative and intraoperative factors. RESULTS: Of the 35,910 cases, 33,484 (93.2%) had a preoperative INR < 1.4; 867 (2.4%) an INR ⩾1.4 and <1.6; 865 (2.4%) an INR ⩾ 1.6 and <1.8 and 692 (1.9%) an INR ⩾ 1.8. A preoperative INR ⩾ 1.8 was independently associated with an increased risk of bleeding requiring transfusion. A preoperative INR ⩾ 1.6 was associated with an increased risk of mortality. CONCLUSIONS: We found that an INR of <1.6 is a safe value for patients who are to undergo surgery for a hip fracture. Below this value, patients avoid an increased risk of both transfusion and 30-day mortality seen with higher INR values. These findings may allow adjustment of preoperative protocols and improve the outcome of hip fracture surgery in this group of patients.

Effect of Faculty Diversity on Minority Student Populations Matching into Orthopaedic Surgery Residency Programs.

Greater faculty diversity within orthopaedic residency programs has been associated with an increased application rate from students of similarly diverse demographic backgrounds. It is unknown whether these underrepresented student populations have an equitable likelihood of being highly ranked and matching at these programs. Thus, we sought to evaluate the relationship between faculty and resident diversity, with a specific focus on sex, racial/ethnic groups that are underrepresented in medicine (URiM), and international medical graduates (IMGs). Methods: The American Orthopaedic Association's Orthopaedic Residency Information Network database was used to collect demographic data on 172 US residency programs. Linear regression analyses were performed to determine the relationship between the proportion of female or URiM attendings at a program and the proportion of female, URiM, or IMG residents or top-ranked applicants (≥25 rank). URiM was defined as "racial and ethnic populations that are underrepresented in the medical profession relative to their numbers in the general population." Results: A mean of 13.55% of attendings were female and 14.14% were URiM. A larger fraction of female attendings was a positive predictor of female residents (p < 0.001). Similarly, a larger percentage of URiM attendings was a positive predictor of URiM residents (p < 0.001), as well as of URiM (p < 0.001) and IMG (p < 0.01) students being ranked highly. There was no significant association between URiM attendings and female residents/overall top-ranked applicants, or vice versa. Conclusions: Residency programs with more female attendings were more likely to match female residents, and programs with more URiM attendings were more likely to highly rank URiM and IMG applicants as well as match URiM residents. Our findings indicate that orthopaedic surgery residencies may be more likely to rank and match female or URiM students at similar proportions to that of their faculty. This may reflect minority students preferentially applying to programs with more diverse faculty because they feel a better sense of fit and are likely to benefit from a stronger support system. Level of Evidence: III.

Towards Visualizing Early-stage Osteonecrosis using Intraoperative Imaging Modalities.

Osteonecrosis of the Femoral Head (ONFH) is a progressive disease characterized by the death of bone cells due to the loss of blood supply. Early detection and treatment of this disease are vital in avoiding Total Hip Replacement. Early stages of ONFH can be diagnosed using Magnetic Resonance Imaging (MRI), commonly used intra-operative imaging modalities such as fluoroscopy frequently fail to depict the lesion. Therefore, increasing the difficulty of intra-operative localization of osteonecrosis. This work introduces a novel framework that enables the localization of necrotic lesions in Computed Tomography (CT) as a step toward localizing and visualizing necrotic lesions in intra-operative images. The proposed framework uses Deep Learning algorithms to enable automatic segmentation of femur, pelvis, and necrotic lesions in MRI. An additional step performs semi-automatic segmentation of these anatomies, excluding the necrotic lesions, in CT. A final step performs pairwise registration of the corresponding anatomies, allowing for the localization and visualization of the necrosis in CT. To investigate the feasibility of integrating the proposed framework in the surgical workflow, we conducted experiments on MRIs and CTs containing early-stage ONFH. Our results indicate that the proposed framework is able to segment the anatomical structures of interest and accurately register the femurs and pelvis of the corresponding volumes, allowing for the visualization and localization of the ONFH in CT and generated X-rays, which could enable intra-operative visualization of the necrotic lesions for surgical procedures such as core decompression of the femur.