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.

Cemented Stem Design in Total Hip Arthroplasty: Fixation Philosophies, Biomechanics, and an Updated Classification System.

There is renewed interest in cemented femoral fixation in total hip arthroplasty in the United States, and to fully appreciate the evolution of cemented femoral stem designs, an understanding of their history and design rationale is essential. To adequately study the outcomes of modern-day designs, a comprehensive classification system is also necessary. The biomechanical principles, failure mechanisms, and clinical outcomes associated with various cemented femoral stems are described in this comprehensive review. In addition, an updated version of an existing classification system is described that incorporates the primary design characteristics which differentiate implants currently in use. In this classification, implants are categorized as taper-slip (Type I), which are subdivided by Anatomic (IA), Double-Taper (IB), and Triple-Taper (IC) with subclassification for Traditional and Line-to-Line implants. Composite beam (Type II) implants are similarly divided into Anatomic (IIA), Straight (IIB), and Wedge (IIC) with subclassification for Polished, Satin, or Roughened finish. This classification system provides a basis for comparing cemented femoral stems, thereby improving our understanding of the effect of design characteristics on survivorship to guide future advancements and improve clinical outcomes.

The weight of complications: high and low BMI have disparate modes of failure in total hip arthroplasty.

BACKGROUND: Body mass index (BMI) has been shown to influence risk for revision total hip arthroplasty (rTHA), but few studies have specifically examined which causes of rTHA are most likely in different BMI classes. We hypothesized that patients in different BMI classes would undergo rTHA for disparate reasons. METHODS: Ninety-eight thousand six hundred seventy patients undergoing rTHA over 2006-2020 were identified in the National Inpatient Sample. Patients were classified as underweight, normal-weight, overweight/obese, or morbidly obese. Multivariable logistic regression was used to analyze the impact of BMI on rTHA for periprosthetic joint infection (PJI), dislocation, periprosthetic fracture (PPF), aseptic loosening, or mechanical complications. Analyses were adjusted for age, sex, race/ethnicity, socioeconomic status, insurance, geographic region, and comorbidities. RESULTS: Compared to normal-weight patients, underweight patients were 131% more likely to have a revision due to dislocation and 63% more likely due to PPF. Overweight/obese patients were 19% less likely to have a revision due to dislocation and 10% more likely due to PJI. Cause for revision in morbidly obese patients was 4s1% less likely to be due to dislocation, 8% less likely due to mechanical complications, and 90% more likely due to PJI. CONCLUSIONS: Overweight/obese and morbidly obese patients were more likely to undergo rTHA for PJI and less likely for mechanical reasons compared to normal weight patients. Underweight patients were more likely to undergo rTHA for dislocation or PPF. Understanding the differences in cause for rTHA among the BMI classes can aid in patient-specific optimization and management to reduce postoperative complications. LEVEL OF EVIDENCE: III.

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.

Impact of Postoperative COVID-19 Infection Status on Outcomes in Elective Primary Total Joint Arthroplasty.

BACKGROUND: Although Coronavirus disease 2019 (COVID-19) infection causes major morbidity and mortality, it is unclear what the impact of postoperative COVID-19 infection is on 30-day outcomes after total joint arthroplasty (TJA). METHODS: There were 2,340 patients who underwent TJA in 2021, identified using the National Surgical Quality Improvement Program database, with 925 total hip arthroplasty (THA) patients (39.5%) and 1,415 total knee arthroplasty (TKA) patients (60.5%), overall. Propensity score matching was implemented using patient demographics and preoperative medical conditions to compare outcomes for postoperative COVID-19-positive and COVID-19-negative patients who underwent TKA or THA. RESULTS: Postoperative COVID-19-positive THA patients were found to have a significantly increased risk of pneumonia (odds ratio [OR] 42.57), sepsis (OR 12.77), readmission (OR 12.06), non-home discharge (OR 3.78), and longer length of stay (hazard ratio 1.62). Postoperative COVID-19-positive TKA patients had an increased risk of 30-day mortality (OR 14.17), superficial infection (OR 3.17), pneumonia (OR 34.68), unplanned intubation (OR 18.31), ventilator use for more than 48 hours (OR 18.31), pulmonary embolism (OR 11.98), urinary tract infection (OR 5.16), myocardial infarction (OR 16.02), deep vein thrombosis (OR 4.69), non-home discharge (OR 1.79), reoperation (OR 3.17), readmission (OR 9.61), and longer length of stay (hazard ratio 1.49). CONCLUSIONS: Patients who contracted COVID-19 within 30 days after TJA were at increased risk of mortalities, medical complications, readmissions, reoperations, and non-home discharges. It is important for orthopedic surgeons to understand these adverse outcomes to better counsel patients and mitigate these risks, particularly in higher risk populations.

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.

Compressed Sensing SEMAC MRI of Hip, Knee, and Ankle Arthroplasty Implants: A 1.5-T and 3-T Intrapatient Performance Comparison for Diagnosing Periprosthetic Abnormalities.

BACKGROUND. The utility of 3-T MRI for diagnosing joint disorders is established, but its performance for diagnosing abnormalities around arthroplasty implants is unclear. OBJECTIVE. The purpose of this study was to compare 1.5-T and 3-T compressed sensing slice encoding for metal artifact correction (SEMAC) MRI for diagnosing peri-prosthetic abnormalities around hip, knee, and ankle arthroplasty implants. METHODS. Forty-five participants (26 women, 19 men; mean age ± SD, 71 ± 14 years) with symptomatic lower extremity arthroplasty (hip, knee, and ankle, 15 each) prospectively underwent consecutive 1.5- and 3-T MRI examinations with intermediate-weighted (IW) and STIR compressed sensing SEMAC sequences. Using a Likert scale, three radiologists evaluated the presence or absence of periprosthetic abnormalities, including bone marrow edema-like signal, osteolysis, stress reaction/fracture, synovitis, and tendon abnormalities and collections; image quality; and visibility of anatomic structures. Statistical analysis included nonparametric comparison and interchangeability testing. RESULTS. For diagnosing periprosthetic abnormalities, 1.5-T and 3-T compressed sensing SEMAC MRI were interchangeable. Across all three joints, 3-T MRI had lower noise than 1.5-T MRI (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [range, 2-5 and 3-5] vs 3 and 3 [range, 2-5 and 2-4]; p < .01 for both), sharper edges (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [both ranges, 2-5] vs 3 and 3 [range, 2-4 and 2-5]; p < .02 and p < .05), and more effective metal artifact reduction (median IW and STIR scores at 3 T vs 1.5 T, 4 and 4 [range, 3-5 and 2-5] vs 4 and 4 [both ranges, 3-5]; p < .02 and p = .72). Agreement was moderate to substantial for image contrast (IW and STIR, 0.66 and 0.54 [95% CI, 0.41-0.91 and 0.29-0.80]; p = .58 and p = .16) and joint capsule visualization (IW and STIR, 0.57 and 0.70 [range, 0.32-0.81 and 0.51-0.89]; p = .16 and p = .19). The bone-implant interface was more visible at 1.5 T (median IW and STIR scores, 4 and 4 [both ranges, 2-5] at 1.5 T vs 3 and 3 [both ranges, 2-5] at 3 T; p = .08 and p = .58), but periprosthetic tissues had superior visibility at 3 T (IW and STIR, 4 and 4 [both ranges, 3-5] at 3 T vs 4 and 4 [ranges, 2-5 and 3-5] at 1.5 T; p = .07 and p = .19). CONCLUSION. Optimized 1.5-T and 3-T compressed sensing SEMAC MRI are interchangeable for diagnosing periprosthetic abnormalities, although metallic artifacts are larger at 3 T. CLINICAL IMPACT. With compressed sensing SEMAC MRI, lower extremity arthroplasty implants can be imaged at 3 T rather than 1.5 T.

Comparing Pain and Pain Coping Mechanisms in Patients Undergoing Total Joint Arthroplasty as Part of a Mission Trip to Those in the United States.

BACKGROUND: Access to total joint arthroplasty can be difficult in low-resource settings. Service trips are conducted to provide arthroplasty care to populations in need around the world. This study aimed to compare the pain, function, surgical expectations, and coping mechanisms of patients from one such service trip to the United States. METHODS: In 2019, the Operation Walk program conducted a service trip in Guyana during which 50 patients had hip or knee arthroplasties. Patient demographics, patient-reported outcome measures, questionnaires assessing pain attitudes and coping, and pain visual analog scales were collected preoperatively and at 3 months postoperatively. These outcomes were compared with a matched cohort of elective total joint arthroplasty at a US tertiary care medical center. There were 37 patients matched between the 2 cohorts. RESULTS: The mission cohort had significantly lower preoperative self-reported function scores than the US cohort (38.3 versus 47.5, P = .003), as well as a significantly larger improvement at 3 months (42.4 versus 26.4, P = .014). The mission cohort had significantly higher initial pain (8.0 versus 7.0, P = .015), but there were no differences with regard to pain at 3 months (P = .420) or change in pain (P = .175). The mission cohort had significantly greater preoperative scores in pain attitude and coping responses. CONCLUSION: Patients in low-resource settings were more likely to have preoperative functional limitations and pain, and they coped with pain through prayer. Understanding the key differences between these 2 types of populations and how they approach pain and functional limitations may help improve care for each group. LEVEL OF EVIDENCE: II, prospective study.

Not All Patients Need Supervised Physical Therapy After Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

Although postoperative physical therapy (PT) has long been considered essential to successful total knee arthroplasty (TKA) recovery, recent literature has suggested that unsupervised home exercise regimens may offer similar benefits to formal supervised sessions. We aimed to compare objectively measured physical function and subjective patient-reported outcomes (PROs) between primary TKA patients who received formal supervised physical therapy sessions and those who received unsupervised home exercise regimens after discharge. Six electronic databases were queried to identify randomized controlled trials comparing supervised physical therapy to unsupervised home exercise regimens in primary TKA patients after discharge. Outcomes of interest included change from baseline in objective measures (knee flexion range of motion (ROM), lower extremity strength, and aerobic capacity) and PROs (physical function and quality of life scores). These outcomes were subdivided into short-term (<6 months from surgery; closest data point to three months is used if multiple measurements were made in this time period) and long-term (≥6 months from surgery; closest data point to 12 months is used if multiple measurements were made in this time period) assessments. A total of 1,884 cases performed in 11 studies were included in this review. There were no significant differences between cohorts with regard to short-term knee flexion ROM (p = 0.7), lower extremity strength (p = 0.6), or patient-reported quality of life (p = 0.5), as well as long-term knee flexion ROM (p = 0.7), patient-reported quality of life (p = 0.2), or patient-reported physical outcome scores (p = 0.3). A small difference in short-term patient-reported physical outcomes was observed in favor of the supervised cohort (standardized mean difference (SMD): 0.3 (95% confidence interval (CI): 0.01, 0.6); I2 = 82%; p = 0.04). Formal supervised physical therapy regimens do not confer clinically significant benefits over unsupervised home exercise regimens following primary TKA. The routine use of supervised physical therapy after discharge may not be warranted. Further study is needed to determine the subset of patients that may benefit from supervised care.

Comparing five equations to calculate estimated glomerular filtration rate to predict acute kidney injury following total joint arthroplasty.

BACKGROUND: Acute kidney injury (AKI) following total joint arthroplasty (TJA) is associated with increased morbidity and mortality. Estimated glomerular filtration rate (eGFR) is used as an indicator of renal function. The purpose of this study was (1) to assess each of the five equations that are used in calculating eGFR, and (2) to evaluate which equation may best predict AKI in patients following TJA. METHODS: The National Surgical Quality Improvement Program (NSQIP) was queried for all 497,261 cases of TJA performed from 2012 to 2019 with complete data. The Modification of Diet in Renal Disease (MDRD) II, re-expressed MDRD II, Cockcroft-Gault, Mayo quadratic, and Chronic Kidney Disease Epidemiology Collaboration equations were used to calculate preoperative eGFR. Two cohorts were created based on the development of postoperative AKI and were compared based on demographic and preoperative factors. Multivariate regression analysis was used to assess for independent associations between preoperative eGFR and postoperative renal failure for each equation. The Akaike information criterion (AIC) was used to evaluate predictive ability of the five equations. RESULTS: Seven hundred seventy-seven (0.16%) patients experienced AKI after TJA. The Cockcroft-Gault equation yielded the highest mean eGFR (98.6 ± 32.7), while the Re-expressed MDRD II equation yielded the lowest mean eGFR (75.1 ± 28.8). Multivariate regression analysis demonstrated that a decrease in preoperative eGFR was independently associated with an increased risk of developing postoperative AKI in all five equations. The AIC was the lowest in the Mayo equation. CONCLUSIONS: Preoperative decrease in eGFR was independently associated with increased risk of postoperative AKI in all five equations. The Mayo equation was most predictive of the development of postoperative AKI following TJA. The mayo equation best identified patients with the highest risk of postoperative AKI, which may help providers make decisions on perioperative management in these patients.

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.

Intraosseous Tibial Resuscitation After a Total Knee Arthroplasty Leading to Osteonecrosis and Loosening of the Tibial Component.

A 51-year-old woman suffered cardiac arrest requiring emergent intraosseous access that abutted the tibial component of her total knee arthroplasty. She developed a wound at the site and knee pain which was concerning for deep infection. Subsequent imaging was consistent with osteonecrosis developing around the tibial component. The component eventually loosened, requiring a revision surgery. Her deep cultures remained negative throughout. Her findings are most consistent with osteonecrosis and aseptic loosening of her prosthesis. While intraosseous access may be beneficial during resuscitation, it has complications. This is the first reported case of osteonecrosis secondary to intraosseous access leading to prosthetic loosening necessitating a revision surgery.

Racial and Ethnic Disparities in Short-Stay Total Knee Arthroplasty.

BACKGROUND: The purpose of this study was to understand racial and ethnic disparities in hospital-based, Medicare-defined outpatient total knee arthroplasty (TKA). We aimed to determine the following: 1) whether there are differences in preoperative characteristics or postoperative outcomes in outpatient TKA between racial/ethnic groups and 2) trends in outpatient TKA volume, based on race/ethnicity. METHODS: This was a retrospective cohort study of a large national database. Outpatient TKAs performed between 2012 and 2018 were identified. Patient demographics, comorbidities, and 30-day postoperative outcomes were compared between White, Black, Asian, and Hispanic patients. RESULTS: Of 54,183 outpatient patients, 85.6% were White, 7.4% Black, 2.6% Asian, and 4.1% Hispanic. Black patients had the highest body mass index, and there were higher rates of diabetes among all minority groups (P < .001). All minority groups were more likely to be discharged to a rehabilitation or a skilled care facility compared to White patients (P < .001). Annual percentage increases in outpatient TKA were most pronounced for Asians and Hispanics and least pronounced among Blacks, when compared to White patients. CONCLUSION: The outcomes of outpatient TKA are impacted by risk factors that reflect underlying disparities in healthcare. As joint arthroplasties have come off the inpatient-only list and procedures move to ambulatory settings, these disparities will likely magnify and impact outcomes, costs, and access points. Extensive preoperative optimization and interventions that target medical and social factors may help to reduce these disparities in TKA and increase access among minority patients. LEVEL OF EVIDENCE: III, retrospective cohort study.

Internal Fixation Versus Hemiarthroplasty for Nondisplaced Femoral Neck Fractures: A Systematic Review and Meta-Analysis.

OBJECTIVE: To compare internal fixation (IF) versus hemiarthroplasty (HA) for elderly individuals (ie, older than 65 years) with nondisplaced (ie, Garden type I or II) femoral neck fracture (FNF). DATA SOURCE: We searched English literature of MEDLINE, PubMed, and Embase from inception to December 4, 2021. STUDY SELECTION: Eligibility criteria were randomized controlled trials (RCTs) compared IF versus HA for elderly individuals with nondisplaced FNF. Primary outcomes were Harris hip score (HHS), quality of life per European Quality of Life 5 Dimension (EQ-5D), and mortality. Secondary outcomes were complications, reoperation, intraoperative bleeding, operation duration, and length of hospital stay. DATA EXTRACTION: Two authors separately extracted data and assessed the risk of bias of the included studies using Cochrane risk-of-bias tool. DATA SYNTHESIS: Three RCTs yielding 400 patients were enrolled, of which 203 (50.7%) underwent IF. Internal fixation was inferior to HA with respect to 6-month HHS [mean difference (MD) = -8.28 (-14.46, -2.10), P = 0.009] and 1-year EQ-5D [MD = -0.07 (-0.14, -0.00), P = 0.04]. The 2 techniques were comparable regarding length of hospital stay (day), HHS at 1 and 2 years, EQ-5D at 2 years, and mortality. IF was inferior to HA in implant-related complication [20.1% vs. 6.0%, relative risk (RR) = 3.18 (1.72, 5.88), P = 0.0002] and reoperation rate [20.1% vs. 6.0%, RR = 3.30 (1.79, 6.08), P = 0.0001]. Hemiarthroplasty had a greater blood loss (mL) [MD = -138.88 (-209.58, -68.18), P = 0.001] and operation duration (min) [MD = -23.27 (-44.95, -1.60), P = 0.04] compared with IF. CONCLUSION: HA is the preferred technique for nondisplaced FNF if early recovery, higher mobility, and better quality of life are priorities. The choice of fixation should be weighed on an individual patient level. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.