Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated with Lower Complication Rates After Primary Total Hip Arthroplasty?

INTRODUCTION: Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize pre-operative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA. METHODS: We identified 613 patients who underwent primary THA in a single institution during a 7-year period, and who had a BMI > 40 recorded 9 to 12 months prior to surgery. Subjects were stratified into three cohorts based on whether their baseline BMI decreased by > 5% (147 patients, 24%), was unchanged (+/-5%) (336 patients, 55%), or increased by > 5% (130 patients, 21%) on the day of surgery. The frequency of 90-day Hip Society and Centers for Medicare & Medicaid Services (CMS) complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists Class (P < 0.001) and hemoglobin A1C (P = 0.011), which were accounted for in a multivariate regression analysis. RESULTS: In univariate analysis, there was a lower incidence of readmission (P = 0.025) and total complications (P = 0.005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-day complications between cohorts (P > 0.05). CONCLUSION: Patients who have a BMI > 40 and achieved a clinically significant (> 5%) BMI reduction prior to THA did not have a lower risk of 90-day complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.

Substantial Weight Loss May Not Improve Early Outcomes of Total Knee Arthroplasty in the Morbidly Obese.

BACKGROUND: Body mass index (BMI) cutoffs for morbidly obese patients otherwise indicated for total knee arthroplasty (TKA) have been widely proposed and implemented, though they remain controversial. Previous studies suggested that a 5% reduction in BMI may be associated with fewer postoperative complications. Thus, the purpose of this study was to determine whether a substantial reduction in preoperative BMI in morbidly obese patients improved 90-day outcomes after TKA. METHODS: There were 1,270 patients who underwent primary TKA at a single institution and had a BMI > 40 recorded during the year prior to surgery. Patients were stratified into three cohorts based on whether their BMI within 3 months to 1 year preoperatively had decreased by ≥ 5% (228 patients [18%]); increased by ≥ 5% (310 [24%]); or remained unchanged (within 5%) (732 [58%]) on the day of surgery. There were several baseline differences between the cohorts with respect to medical comorbidities. The rate of 90-day complications and six-week patient-reported outcome measures were compared via univariate and multivariable analyses. RESULTS: On univariate analysis, individual and total complication rates were similar between the cohorts (P > .05). On multivariable logistic regression, the risk of complications was similar in patients who had decreased versus unchanged BMI (OR [odds ratio] 1.0; P = .898). However, there was a higher risk of complications in the increased BMI cohort compared to those patients who had an unchanged BMI (OR 1.5; P = .039). The six-week patient-reported outcome measures were similar between the cohorts. CONCLUSIONS: Patients who have a BMI > 40 who achieved a meaningful reduction in BMI prior to TKA did not have a lower rate of 90-day complications than those whose BMI remained unchanged. Furthermore, considering that nearly one in four patients experienced a significant increase in BMI while awaiting surgery, postponing TKA may actually be detrimental.

Obesity Severity Does Not Associate With Rate, Timing, or Invasiveness of Early Reinterventions After Total Knee Arthroplasty.

BACKGROUND: The use of body mass index (BMI) cutoff values has been suggested for proceeding with total knee arthroplasty (TKA) in obese patients. However, the relationship between obesity severity and early reoperations after TKA is poorly defined. This study evaluated whether increased World Health Organization (WHO) obesity class was associated with risk, severity, and timing of reintervention within one year after TKA. METHODS: There were 8,674 patients from our institution who had a BMI ≥ 30 and underwent unilateral TKA for primary osteoarthritis between 2016 and 2021. Patients were grouped by WHO obesity class: 4,456 class I (51.5%), 2,527 class II (29.2%), and 1,677 class III (19.4%). A chart review was performed to determine patient characteristics and identify patients who underwent any closed or open reintervention requiring anesthesia within the first postoperative year. Regression analyses were performed to identify variables associated with increased odds ratios (ORs) for requiring a reintervention, its timing, and invasiveness. RESULTS: There were 158 patients (1.8%) who required at least one reintervention, and 15 patients (0.2%) required at least 2 reinterventions. Reintervention rates for obesity classes I, II, and III were 1.8% (n = 81), 2.0% (n = 51), and 1.4% (n = 23), respectively. There were 65 closed procedures (41.1%), 47 minor procedures (29.7%), 34 open with or without liner exchange (21.5%), and 12 revisions with component exchange (7.6%). Obesity class was not associated with reintervention rate (P = .3), timing (P = .36), or invasiveness (P = .93). Diabetes (odds ratio [OR] = 2.47; P = .008) was associated with a need for reintervention. Non-Caucasian race (OR = 1.7; P = .01) and Charlson comorbidity index (OR = 2.1; P = .008) were associated with earlier reintervention. No factors were associated with the invasiveness of reintervention. CONCLUSIONS: The WHO obesity class did not associate with rate, timing, or invasiveness of reintervention after TKA in obese patients. These findings suggest that policies that restrict the indication for elective TKA based only on a BMI limit have limited efficacy in reducing early reintervention after TKA in obese patients. LEVEL OF EVIDENCE: III.

A single-center, open-label, randomized, parallel-group trial to pilot the effectiveness of a peer coach behavioral intervention versus an active control in reducing anxiety and depression in patients scheduled for total knee replacement.

BACKGROUND: Moving Well is a behavioral intervention for patients with knee osteoarthritis (KOA) scheduled for a total knee replacement (TKR). The objective of this intervention is to help patients with KOA mentally and physically prepare for and recover from TKR. METHODS: This is an open-label pilot randomized clinical trial that will test the feasibility and effectiveness of the Moving Well intervention compared to an attention control group, Staying Well, to reduce symptoms of anxiety and depression in patients with KOA undergoing TKR. The Moving Well intervention is guided by Social Cognitive Theory. During this 12-week intervention, participants will receive 7 weekly calls before surgery and 5 weekly calls after surgery from a peer coach. During these calls, participants will be coached to use principles of cognitive behavioral therapy (CBT), stress reduction techniques, and will be assigned an online exercise program, and self-monitoring activities to complete on their own time throughout the program. Staying Well participants will receive weekly calls of similar duration from research staff to discuss a variety of health topics unrelated to TKR, CBT, or exercise. The primary outcome is the difference in levels of anxiety and/or depression between participants in the Moving Well and Staying Well groups 6 months after TKR. DISCUSSION: This study will pilot test the feasibility and effectiveness of Moving Well, a peer coach intervention, alongside principles of CBT and home exercise, to help patients with KOA mentally and physically prepare for and recover from TKR. TRIAL REGISTRATION: Clinicaltrials.gov. NCT05217420; Registered: January 31, 2022.

Healthcare disparities: patients' perspectives on barriers to joint replacement.

OBJECTIVE: Racial and ethnic disparities in arthroplasty utilization are evident, but the reasons are not known. We aimed to identify concerns that may contribute to barriers to arthroplasty from the patient's perspective. METHODS: We identified patients' concerns about arthroplasty by performing a mixed methods study. Themes identified during semi-structured interviews with Black and Hispanic patients with advanced symptomatic hip or knee arthritis were used to develop a questionnaire to quantify and prioritize their concerns. Multiple linear and logistic regression analyses were conducted to determine the association between race/ethnicity and the importance of each theme. Models were adjusted for sex, insurance, education, HOOS, JR/KOOS, JR, and discussion of joint replacement with a doctor. RESULTS: Interviews with eight participants reached saturation and provided five themes used to develop a survey answered by 738 (24%) participants; 75.5% White, 10.3% Black, 8.7% Hispanic, 3.9% Asian/Other. Responses were significantly different between groups (p < 0.05). Themes identified were "Trust in the surgeon" "Recovery", "Cost/Insurance", "Surgical outcome", and "Personal suitability/timing". Compared to Whites, Blacks were two-fold, Hispanics four-fold more likely to rate "Trust in the surgeon" as very/extremely important. Blacks were almost three times and Hispanics over six times more likely to rate "Recovery" as very/extremely important. CONCLUSION: We identified factors of importance to patients that may contribute to barriers to arthroplasty, with marked differences between Blacks, Hispanics, and Whites.

Racial and Ethnic Disparities in Total Joint Arthroplasty Care: A Contemporary Systematic Review and Meta-Analysis.

BACKGROUND: Total joint arthroplasty (TJA) is one of the most common surgical procedures in the United States; however, racial and ethnic disparities in utilizations and outcomes have been well documented. This systematic review and meta-analysis investigated associations between race/ethnicity and several metrics in total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: In August 2021, PubMed, Scopus, CINAHL, and SPORTDiscus databases were queried. Sixty three studies investigating racial/ethnic disparities in TJA utilizations, complications, mortalities, lengths of stay (LOS), discharge dispositions, readmissions, and reoperations were included. Study quality was assessed using a modified Newcastle-Ottawa Scale. RESULTS: A majority of studies demonstrated disparities in TJA utilizations and outcomes. Black patients exhibited higher rates of 30-day complications (THA odds ratio [OR] 1.18, 95% confidence interval [CI] 1.08-1.29; TKA OR 1.20, 95% CI 1.10-1.31), 30-day mortality (THA OR 1.27, 95% CI 1.08-1.48), prolonged LOS (THA mean difference [MD] +0.27 days, 95% CI 0.21-0.33; TKA MD +0.30 days, 95% CI 0.20-0.40), nonhome discharges (THA OR 1.47, 95% CI 1.37-1.57; TKA OR 1.65, 95% CI 1.38-1.96), and 30-day readmissions (THA OR 1.13, 95% CI 1.08-1.19; TKA OR 1.19, 95% CI 1.16-1.21) than White patients. Rates of complications (THA 1.18, 95% CI 1.03-1.36), prolonged LOS (TKA MD +0.20 days, 95% CI 0.17-0.23), and nonhome discharges (THA OR 1.26, 95% CI 1.10-1.45; TKA OR 1.37, 95% CI 1.22-1.53) were also increased among Hispanic patients, while Asian patients experienced longer LOS (TKA MD +0.09 days, 95% CI 0.05-0.12) but fewer readmissions. Outcomes among American Indian-Alaska Native and Pacific Islander patients were infrequently reported but similarly inequitable. CONCLUSION: Racial and ethnic disparities in TJA utilizations and outcomes are apparent, with minority patients often demonstrating lower rates of utilizations and worse postoperative outcomes than White patients. Continued research is needed to evaluate the efficacy of recent efforts dedicated to eliminating inequalities in TJA care. LEVEL OF EVIDENCE: IV.

Emerging Racial Disparities in Outpatient Utilization of Total Joint Arthroplasty.

BACKGROUND: Racial and ethnic disparities within the field of total joint arthroplasty (TJA) have been extensively reported. To date, however, it remains unknown how these disparities have translated to the outpatient TJA (OP-TJA) setting. The purposes of this study were to compare relative OP-TJA utilization rates between White and Black patients from 2011-2019 and assess how these differences in utilization have evolved over time. METHODS: We conducted a retrospective review from 2011-2019 using the National Surgical Quality Improvement Program (NSQIP). Differences in the relative utilization of OP (same-day discharge) versus inpatient TJA between White and Black patients were assessed and trended over time. Multivariable logistic regressions were run to adjust for baseline patient factors and comorbidities. RESULTS: During the study period, Black patients were significantly less likely to undergo OP-TJA when compared to White patients (P < .001 for both outpatient total knee arthroplasty and outpatient total hip arthroplasty [OP-THA]). From 2011 to 2019, an emerging disparity was found in outpatient total knee arthroplasty and OP-THA utilization between White and Black patients (eg, White versus Black OP-THA: 0.4% versus 0.6% in 2011 compared with 10.2% versus 5.9% in 2019, Ptrend < .001). These results held in all adjusted analyses. CONCLUSION: In this study we found evidence of emerging and worsening racial disparities in the relative utilization of OP-TJA procedures between White and Black patients. These results highlight the need for early intervention by orthopaedic surgeons and policy makers alike to address these emerging inequalities in access to care before they become entrenched within our systems of orthopaedic care.

Bilateral vs Unilateral Total Knee Arthroplasty: Racial Variation in Utilization and In-Hospital Major Complication Rates.

BACKGROUND: We sought to examine bilateral total knee arthroplasty (BTKA) vs unilateral TKA (UTKA) utilization and in-hospital complications comparing African Americans (AAs) and Whites. METHODS: In this retrospective analysis of patients ≥50 years who underwent elective primary TKA, the (2007-2016) database of the Healthcare Cost and Utilization Project (National Inpatient Sample) was used. We computed differences in temporal trends in utilization and major in-hospital complication rates of BTKA vs UTKA comparing AAs and Whites. We performed multivariable logistic regression models to assess racial differences in trends adjusting for individual-, hospital- and community-level variables. Discharge weights were used to enable nationwide estimates. We used multiple imputation procedures to impute values for 12% missing race information. RESULTS: An estimated 276,194 BTKA and 5,528,429 UTKA were performed in the US. The proportion of BTKA among all TKAs declined, and AAs were significantly less likely to undergo BTKA compared to Whites throughout the study period (trend P = .01). In-hospital complication rates for UTKA were higher in AAs compared to Whites throughout the study period (trend P < .0001). However, for BTKA, the in-hospital complication rates varied between Whites and AAs throughout the study period (trend P = .09). CONCLUSION: In this nationwide sample of patients who underwent total knee arthroplasty from 2007 to 2016, the utilization of BTKA was higher in Whites compared to AAs. On the other hand, while AAs have consistently higher in-hospital complication rates in UTKA over the time period, this pattern was not consistent for BTKA.

Perception of Risk: A Poll of American Association of Hip and Knee Surgeons Members.

BACKGROUND: Providers of total hip and knee replacements are being judged regarding quality/cost by payers using competition-based performance measures with poor medical and no socioeconomic risk adjustment. Providers might assume that other providers shed risk and the perception of added risk can influence practice. A poll was collected to examine such perceptions. METHODS: In 2019 a poll was sent to the 2800 surgeon members of the American Association of Hip and Knee Surgeons using Survey Monkey while protecting respondent anonymity/confidentiality. The questions asked whether the perception of poorly risk-adjusted medical comorbidities and socioeconomic risk factors influence surgeons to selectively offer surgery. RESULTS: There were 474 surgeon responses. Prior to elective total hip arthroplasty/total knee arthroplasty, 95% address modifiable risk factors; 52% require a body mass index <40, 64% smoking cessation, 96% an adequate hemoglobin A1C; 82% check nutrition; and 63% expect control of alcohol 2. Due to lack of socioeconomic risk adjustment, 83% reported feeling pressure to avoid/restrict access to patients with limited social support, specifically the following: Medicaid/underinsured, 81%; African Americans, 29%; Hispanics/ethnicities, 27%; and low socioeconomic status, 73%. Of the respondents, 93% predicted increased access to care with more appropriate risk adjustment. CONCLUSION: Competition-based quality/cost performance measures influence surgeons to focus on medical risk factors in offering lower extremity arthroplasty. The lack of socioeconomic risk adjustment leads to perceptions of added risk from such factors as well. This leads to marginal loss of access for patients within certain medical and socioeconomic classes, contributing to existing healthcare disparities. This represents an unintended consequence of competition-based performance measures.

Assessment of a Satisfaction Measure for Use After Primary Total Joint Arthroplasty.

BACKGROUND: Patient satisfaction after total hip (THA) and total knee arthroplasty (TKA) is a core outcome selected by the Outcomes Measurement in Rheumatology. Up to 20% of THA/TKA patients are dissatisfied. Improving patient satisfaction is hindered by the lack of a validated measurement tool that can accurately measure change. METHODS: The psychometric properties of a proposed satisfaction instrument, consisting of 4 questions rated on a Likert scale, scored 1-100, were tested for validity, reliability, and sensitivity to change using data collected between 2007 and 2011 in an arthroplasty registry. RESULTS: We demonstrated construct validity by confirming our hypothesis; satisfaction correlated with similar constructs. Satisfaction correlated moderately with pain relief (TKA ρ = 0.61, THA ρ = 0.47) and function (TKA ρ = 0.65, THA ρ = 0.51) at 2 years; there was no correlation with baseline/preoperative pain/function values, as expected. Overall Cronbach's alpha >0.88 confirmed internal consistency. Test-retest reliability with weighted kappa ranged 0.60-0.75 for TKA and 0.36-0.56 for THA. Hip disability and Osteoarthritis Outcome Score/Knee injury and Osteoarthritis Outcome Scores quality of life improvement (>30 points) corresponds to a mean satisfaction score of 93.2 (standard deviation, 11.5) after THA and 90.4 (standard deviation, 13.8) after TKA, and increasing relief of pain and functional improvement increased the strength of their association with satisfaction. The satisfaction measure has no copyright and is available free of cost and represents minimal responder burden. CONCLUSION: Patient satisfaction with THA/TKA can be measured with a validated 4-item questionnaire. This satisfaction measure can be included in a total joint arthroplasty core measurement set for total joint arthroplasty trials.

Validation of the Hip Disability and Osteoarthritis Outcome Score and Knee Injury and Osteoarthritis Outcome Score Pain and Function Subscales for Use in Total Hip Replacement and Total Knee Replacement Clinical Trials.

BACKGROUND: Total hip replacement (THR)/total knee replacement (TKR) studies do not uniformly measure patient centered domains, pain, and function. We aim to validate existing measures of pain and function within subscales of standard instruments to facilitate measurement. METHODS: We evaluated baseline and 2-year pain and function for THR and TKR using Hip disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS), with primary unilateral TKR (4796) and THR (4801). Construct validity was assessed by correlating HOOS/KOOS pain and activities of daily living (ADL), function quality of life (QOL), and satisfaction using Spearman correlation coefficients. Patient relevant thresholds for change in pain and function were anchored to improvement in QOL; minimally clinically important difference (MCID) corresponded to "a little improvement" and a really important difference (RID) to a "moderate improvement." Pain and ADL function scores were compared by quartiles using Kruskal-Wallis. RESULTS: Two-year HOOS/KOOS pain and ADL function correlated with health-related QOL (KOOS pain and Short Form 12 Physical Component Scale ρ = 0.54; function ρ = 0.63). Comparing QOL by pain and function quartiles, the highest levels of pain relief and function were associated with the most improved QOL. MCID for pain was estimated at ≥20, and the RID ≥29; MCID for function ≥14, and the RID ≥23. The measures were responsive to change with large effect sizes (≥1.8). CONCLUSION: We confirm that HOOS/KOOS pain and ADL function subscales are valid measures of critical patient centered domains after THR/TKR, and achievable thresholds anchored to improved QOL. Cost-free availability and brevity makes them feasible, to be used in a core measurement set in total joint replacement trials.

A Fresh Perspective on a Familiar Problem: Examining Disparities in Knee Osteoarthritis Using a Markov Model.

BACKGROUND: Disparities in the presentation of knee osteoarthritis (OA) and in the utilization of treatment across sex, racial, and ethnic groups in the United States are well documented. OBJECTIVES: We used a Markov model to calculate lifetime costs of knee OA treatment. We then used the model results to compute costs of disparities in treatment by race, ethnicity, sex, and socioeconomic status. RESEARCH DESIGN: We used the literature to construct a Markov Model of knee OA and publicly available data to create the model parameters and patient populations of interest. An expert panel of physicians, who treated a large number of patients with knee OA, constructed treatment pathways. Direct costs were based on the literature and indirect costs were derived from the Medical Expenditure Panel Survey. RESULTS: We found that failing to obtain effective treatment increased costs and limited benefits for all groups. Delaying treatment imposed a greater cost across all groups and decreased benefits. Lost income because of lower labor market productivity comprised a substantial proportion of the lifetime costs of knee OA. Population simulations demonstrated that as the diversity of the US population increases, the societal costs of racial and ethnic disparities in treatment utilization for knee OA will increase. CONCLUSIONS: Our results show that disparities in treatment of knee OA are costly. All stakeholders involved in treatment decisions for knee OA patients should consider costs associated with delaying and forgoing treatment, especially for disadvantaged populations. Such decisions may lead to higher costs and worse health outcomes.

Can a Strategic Pipeline Initiative Increase the Number of Women and Underrepresented Minorities in Orthopaedic Surgery?

BACKGROUND: Women and minorities remain underrepresented in orthopaedic surgery. In an attempt to increase the diversity of those entering the physician workforce, Nth Dimensions implemented a targeted pipeline curriculum that includes the Orthopaedic Summer Internship Program. The program exposes medical students to the specialty of orthopaedic surgery and equips students to be competitive applicants to orthopaedic surgery residency programs. The effect of this program on women and underrepresented minority applicants to orthopaedic residencies is highlighted in this article. QUESTIONS/PURPOSES: (1) For women we asked: is completing the Orthopaedic Summer Internship Program associated with higher odds of applying to orthopaedic surgery residency? (2) For underrepresented minorities, is completing the Orthopaedic Summer Internship Program associated with higher odds of applying to orthopaedic residency? METHODS: Between 2005 and 2012, 118 students completed the Nth Dimensions/American Academy of Orthopaedic Surgeons Orthopaedic Summer Internship Program. The summer internship consisted of an 8-week clinical and research program between the first and second years of medical school and included a series of musculoskeletal lectures, hands-on, practical workshops, presentation of a completed research project, ongoing mentoring, professional development, and counselling through each participant's subsequent years of medical school. In correlation with available national application data, residency application data were obtained for those Orthopaedic Summer Internship Program participants who applied to the match between 2011 through 2014. For these 4 cohort years, we evaluated whether this program was associated with increased odds of applying to orthopaedic surgery residency compared with national controls. For the same four cohorts, we evaluated whether underrepresented minority students who completed the program had increased odds of applying to an orthopaedic surgery residency compared with national controls. RESULTS: Fifty Orthopaedic Summer Internship scholars applied for an orthopaedic residency position. For women, completion of the Orthopaedic Summer Internship was associated with increased odds of applying to orthopaedic surgery residency (after summer internship: nine of 17 [35%]; national controls: 800 of 78,316 [1%]; odds ratio [OR], 51.3; 95% confidence interval [CI], 21.1-122.0; p < 0.001). Similarly, for underrepresented minorities, Orthopaedic Summer Internship completion was also associated with increased odds of orthopaedic applications from 2011 to 2014 (after Orthopaedic Summer Internship: 15 of 48 [31%]; non-Orthopaedic Summer Internship applicants nationally: 782 of 25,676 [3%]; OR, 14.5 [7.3-27.5]; p < 0.001). CONCLUSIONS: Completion of the Nth Dimensions Orthopaedic Summer Internship Program has a positive impact on increasing the odds of each student participant applying to an orthopaedic surgery residency program. This program may be a key factor in contributing to the pipeline of women and underrepresented minorities into orthopaedic surgery. LEVEL OF EVIDENCE: Level III, therapeutic study.

Disparities in TKA Outcomes: Census Tract Data Show Interactions Between Race and Poverty.

BACKGROUND: Race is an important predictor of TKA outcomes in the United States; however, analyses of race can be confounded by socioeconomic factors, which can result in difficulty determining the root cause of disparate outcomes after TKA. QUESTIONS/PURPOSES: We asked: (1) Are race and socioeconomic factors at the individual level associated with patient-reported pain and function 2 years after TKA? (2) What is the interaction between race and community poverty and patient-reported pain and function 2 years after TKA? METHODS: We identified all patients undergoing TKA enrolled in a hospital-based registry between 2007 and 2011 who provided 2-year outcomes and lived in New York, Connecticut, or New Jersey. Of patients approached to participate in the registry, more than 82% consented and provided baseline data, and of these patients, 72% provided 2-year data. Proportions of patients with complete followup at 2 years were lower among blacks (57%) than whites (74%), among patients with Medicaid insurance (51%) compared with patients without Medicaid insurance (72%), and among patients without a college education (67%) compared with those with a college education (71%). Our final study cohort consisted of 4035 patients, 3841 (95%) of whom were white and 194 (5%) of whom were black. Using geocoding, we linked individual-level registry data to US census tracts data through patient addresses. We constructed a multivariate linear mixed-effect model in multilevel frameworks to assess the interaction between race and census tract poverty on WOMAC pain and function scores 2 years after TKA. We defined a clinically important effect as 10 points on the WOMAC (which is scaled from 1 to 100 points, with higher scores being better). RESULTS: Race, education, patient expectations, and baseline WOMAC scores are all associated with 2-year WOMAC pain and function; however, the effect sizes were small, and below the threshold of clinical importance. Whites and blacks from census tracts with less than 10% poverty have similar levels of pain and function 2 years after TKA (WOMAC pain, 1.01 ± 1.59 points lower for blacks than for whites, p = 0.53; WOMAC function, 2.32 ± 1.56 lower for blacks than for whites, p = 0.14). WOMAC pain and function scores 2 years after TKA worsen with increasing levels of community poverty, but do so to a greater extent among blacks than whites. Disparities in pain and function between blacks and whites are evident only in the poorest communities; decreasing in a linear fashion as poverty increases. In census tracts with greater than 40% poverty, blacks score 6 ± 3 points lower (worse) than whites for WOMAC pain (p = 0.03) and 7 ± 3 points lower than whites for WOMAC function (p = 0.01). CONCLUSIONS: Blacks and whites living in communities with little poverty have similar patient-reported TKA outcomes, whereas in communities with high levels of poverty, there are important racial disparities. Efforts to improve TKA outcomes among blacks will need to address individual- and community-level socioeconomic factors. LEVEL OF EVIDENCE: Level III, therapeutic study.

Systemic Lupus Erythematosus Does Not Increase Risk of Adverse Events in the First 6 Months After Total Knee Arthroplasty.

BACKGROUND: Increasing numbers of patients with systemic lupus erythematosus (SLE) are undergoing total knee arthroplasty (TKA). Whether postsurgical adverse events (AEs) are higher in patients with SLE than patients with osteoarthritis (OA) is unknown. OBJECTIVES: This study aims to compare AEs within 6 months of TKA. METHODS: Patients in a single institution's arthroplasty and SLE registries who underwent TKA from 2007 to 2014 were eligible. SLE cases were matched 1:2 to OA on age, sex, year of TKA, and procedure type. AEs were collected through chart review and registry responses. Baseline characteristics were compared and regression analysis performed to determine predictors of AEs. RESULTS: Fifty-two SLE TKA were matched to 104 OA TKA. There was no difference in follow-up between groups. SLE patients had more comorbidities (≥1 Charlson-Deyo comorbidity: SLE 38.4% vs. OA 17.3%; P-value < 0.001) and steroid use (preoperative [SLE 28.8% vs. OA 1.9%, P-value < 0.001] and perioperative "stress-dose" [30.8% vs. 2.9%, P-value = 0.01]). SLE patients did not experience more major (SLE 25.0% vs. OA 19.2%; P-value = 0.41), minor (15.4% vs. 10.6%; P-value = 0.39), or total (38.5% vs. 27.9%; P-value = 0.18) AEs. AEs were not increased among patients on stress-dose steroids. In a multiple logistic regression analysis controlling for comorbidities and diagnosis, neither SLE (OR 1.61, 95% CI 0.74-3.50) nor >1 comorbidity (OR 1.05, 95% CI 0.46-2.39) was an independent risk factor for AEs. CONCLUSION: SLE is not an independent risk factor for increased AEs 6 months after TKA. Stress-dose steroid use does not heighten AE risk. These findings should inform recommendations for SLE patients considering TKA.

Do patient race and sex change surgeon recommendations for TKA?

BACKGROUND: Prior investigations have suggested that physician-related factors may contribute to differential use of TKA among women and ethnic minorities. We sought to evaluate the effect of surgeon bias on recommendations for TKA. QUESTIONS/PURPOSE: Using an experimental approach with standardized patient scenarios, we sought to evaluate surgeon recommendations regarding TKA, specifically to determine whether recommendations for TKA are influenced by (1) patient race, and (2) patient sex. METHODS: We developed four computerized scenarios for all combinations of race (white or black) and sex (male or female) for otherwise similar patients with end-stage knee osteoarthritis. Patients gave an orthopaedic history of 2 years worsening pain with decreased functional status and failure of oral antiinflammatory medications and corticosteroid intraarticular injections. Orthopaedic surgeons attending the 2012 annual meetings of the New York State Society of Orthopaedic Surgeons and American Association of Hip and Knee Surgeons were recruited for the study. Surgeons passing an open recruitment table at each meeting were asked to participate. Of the 1111 surgeons in attendance at either meeting, 113 (10.2%) participated in the study. All participants viewed the "control" patient's story (white male) and were randomized to view one of the three "experimental" scenarios (white female, black male, black female). After viewing each scenario, the participants were anonymously asked whether they would recommend TKA. An a priori power analysis showed that 112 participants were needed to detect a 15% difference in the likelihood of recommending surgery for white versus nonwhite patients in the test scenarios evaluated with 90% power at a level of significance of 0.05. RESULTS: Of the 39 surgeons who viewed the white male plus black female scenario, there were 33 (85%) concordant responses (TKA offered to both patients) and six discordant responses (TKA offered to only one of the patients), with no effect of patient race and sex (p = 0.99). Of the 37 surgeons who viewed the white male plus black male scenario, there were 33 (89%) concordant responses and four discordant responses, with no effect of patient race (p = 0.32). Of the 37 surgeons who viewed the white male plus white female scenario, there were 30 (77%) concordant responses and seven discordant responses, with no effect of patient sex (p = 0.71). CONCLUSION: After orthopaedic surgeons viewed video scenarios of patients with end-stage knee osteoarthritis, patient race and sex were not associated with a different likelihood of a surgical recommendation. Our findings support the notion that patient race and sex may be less influential on decision making when there are strong clinical data to support a decision. Physician bias may have a greater effect on decision making in situations where the indications for surgery are less clear.

Electrical double layers and differential capacitance in molten salts from density functional theory.

Classical density functional theory (DFT) is used to calculate the structure of the electrical double layer and the differential capacitance of model molten salts. The DFT is shown to give good qualitative agreement with Monte Carlo simulations in the molten salt regime. The DFT is then applied to three common molten salts, KCl, LiCl, and LiKCl, modeled as charged hard spheres near a planar charged surface. The DFT predicts strong layering of the ions near the surface, with the oscillatory density profiles extending to larger distances for larger electrostatic interactions resulting from either lower temperature or lower dielectric constant. Overall the differential capacitance is found to be bell-shaped, in agreement with recent theories and simulations for ionic liquids and molten salts, but contrary to the results of the classical Gouy-Chapman theory.