Racialized Inequities in Knee Arthroplasty Receipt After Osteoarthritis Diagnosis in the US Military Health System.

OBJECTIVE: The goal was to evaluate institutional inequities in the US Military Health System in knee arthroplasty receipt within three years of knee osteoarthritis diagnosis when accounting for other treatments received (eg, physical therapy, medications). METHODS: In this retrospective observational cohort study, medical record data of patients (n = 29,734) who received a primary osteoarthritis diagnosis in the US Military Health System between January 2016 and January 2020 were analyzed. Data included receipt of physical therapy one year before diagnosis and up to three years after diagnosis, prediagnosis opioid and nonopioid prescription receipt, health-related factors associated with levels of racism, and the primary outcome, knee arthroplasty receipt within three years after diagnosis. RESULTS: In a generalized additive model with time-varying covariates, Asian and Pacific Islander (incidence rate ratio [IRR] 0.58, 95% confidence interval [CI] 0.45-0.74), Black (IRR 0.52, 95%CI 0.46-0.59), and Latine (IRR 0.66, 95%CI 0.52-0.85) patients experienced racialized inequities in knee arthroplasty receipt, relative to white patients (all P < 0.001). CONCLUSIONS: In the present sample, Asian and Pacific Islander, Black, and Latine patients were significantly less likely to receive a knee arthroplasty, relative to white patients. Taken together, system-level resources are needed to identify and address mechanisms underlying institutional inequities in knee arthroplasty receipt, such as factors related to systemic and structural, institutional, and personally mediated racism.

Clinical three-dimensional anatomy of the femur considering navigation-aided surgery of total knee arthroplasty in Japanese patients.

PURPOSE: Few studies exist regarding sagittal alignment describing femur morphology in navigation-aided surgery. This study investigated the three-dimensional (3D) sagittal femoral alignment of the whole femur. METHODS: Seventy-three consecutive patients (59 females, 14 males, mean age: 76.1 years), yielding 140 femurs, were included in this study. A computed-tomography-based patient-specific 3D femur model was used to define a mechanical axis-based reference plane. Proximal and distal femoral axis angles (PFA, DFA) to the reference plane were measured in 3D using custom software. PFA and DFA represent the proximal and distal inclination of the femoral anatomical axis in sagittal plane, respectively. RESULTS: PFA (10.6 ± 1.5°) was greater than DFA (2.6 ± 1.6°; P < 0.0001). DFA in females (2.3 ± 1.4°) was smaller than in males (3.9 ± 1.7°; P < 0.0001). CONCLUSION: This is the first report of measurement of femoral sagittal alignment related to both 3D anatomy and decision making of femoral flexion angle using navigation surgery for total knee arthroplasty. This report shows a robust DFA measurement that could be used as a template for femoral implants flexion angle when performing both conventional and navigated total knee arthroplasty.

Racial Disparities in Rates of Revision and use of Modern Features in Total Knee Arthroplasty, a National Registry Study.

BACKGROUND: The purpose of our study was to investigate the association of race and ethnicity with rates of modern implant use and postoperative outcomes in total knee arthroplasty (TKA) using the American Academy of Orthopaedic Surgeons American Joint Replacement Registry. METHODS: Adult TKAs from 2012 to 2020 were queried from the American Joint Replacement Registry. A total of 1,121,457 patients were available for analysis for surgical features and 1,068,210 patients for analysis of outcomes. Mixed-effects multivariable logistic regression models were used to examine the association of race with each individual surgical feature (unicompartmental knee arthroplasty (UKA) and robotic-assisted TKA (RA-TKA)) and 30- and 90-day readmission. A proportional subdistribution hazard model was used to model the risk of revision TKA. RESULTS: On multivariate analyses, compared to White patients, Black (odds ratio (OR): 0.52 P < .0001), Hispanic (OR 0.75 P < .001), and Native American (OR: 0.69 P = .0011) patients had lower rates of UKA, while only Black patients had lower rates of RA-TKA (OR = 0.76 P < .001). White (hazard ratio (HR) = 0.8, P < .001), Asian (HR = 0.51, P < .001), and Hispanic-White (HR = 0.73, P = .001) patients had a lower risk of revision TKA than Black patients. Asian patients had a lower revision risk than White (HR = 0.64, P < .001) and Hispanic-White (HR = 0.69, P = .011) patients. No significant differences existed between groups for 30- or 90-day readmissions. CONCLUSION: Black, Hispanic, and Native American patients had lower rates of UKA compared to White patients, while Black patients had lower rates of RA-TKA compared to White, Asian, and Hispanic patients. Black patients also had higher rates of revision TKA than other races.

Chronic Pain Severity and Sociodemographics: An Evaluation of the Neurobiological Interface.

Chronic pain is variably associated with brain structure. Phenotyping based on pain severity may address inconsistencies. Sociodemographic groups also differ in the experience of chronic pain severity. Whether differences by chronic pain severity and/or sociodemographic groups are indicated in pain-related areas of the brain is unknown. Relations between 2 measures of chronic pain severity and brain structure via T1-weighted MRI were investigated and sociodemographic group differences explored. The observational study included 142 community-dwelling (68 non-Hispanic Black [NHB] and 74 non-Hispanic White [NHW]) adults with/at risk for knee osteoarthritis. Relationships between chronic pain severity, sociodemographic groups, and a priori selected brain structures (postcentral gyrus, insula, medial orbitofrontal, anterior cingulate, rostral middle frontal gyrus, hippocampus, amygdala, thalamus) were explored. Chronic pain severity associated with cortical thickness. NHB participants reported lower sociodemographic protective factors and greater clinical pain compared to NHWs who reported higher sociodemographic protective factors and lower clinical pain. Greater chronic pain severity was associated with smaller amygdala volumes in the NHB group and larger amygdala volumes in the NHW group. Brain structure by chronic pain stage differed between and within sociodemographic groups. Overall, chronic pain severity and sociodemographic factors are associated with pain-related brain structures. Our findings highlight the importance of further investigating social and environmental contributions in the experience of chronic pain to unravel the complex array of factors contributing to disparities. PERSPECTIVE: The study presents data demonstrating structural brain relationships with clinical pain severity, characteristic pain intensity and chronic pain stage, differ by sociodemographic groups. Findings yield insights into potential sources of previous inconsistent pain-brain relationships and highlights the need for future investigations to address social and environmental factors in chronic pain disparities research.

A Mediation Appraisal of Catastrophizing, Pain-Related Outcomes, and Race in Adults With Knee Osteoarthritis.

The current cross-sectional study investigates whether pain catastrophizing mediates the relationship between ethnicity/race and pain, disability and physical function in individuals with knee osteoarthritis. Furthermore, this study examined mediation at 2-year follow-up. Participants included 187 community-dwelling adults with unilateral or bilateral knee pain who screened positive for knee osteoarthritis. Participants completed several self-reported pain-related measures and pain catastrophizing subscale at baseline and 2-year follow-up. Non-Hispanic Black (NHB) adults reported greater pain, disability, and poorer functional performance compared to their non-Hispanic White (NHW) counterparts (Ps < .05). NHB adults also reported greater catastrophizing compared to NHW adults. Mediation analyses revealed that catastrophizing mediated the relationship between ethnicity/race and pain outcome measures. Specifically, NHB individuals reported significantly greater pain and disability, and exhibited lower levels of physical function, compared to NHW individuals, and these differences were mediated by higher levels of catastrophizing among NHB persons. Catastrophizing was a significant predictor of pain and disability 2-years later in both ethnic/race groups. These results suggest that pain catastrophizing is an important variable to consider in efforts to reduce ethnic/race group disparities in chronic pain. The findings are discussed in light of structural/systemic factors that may contribute to greater self-reports of pain catastrophizing among NHB individuals. PERSPECTIVE: The current study examines whether pain catastrophizing mediates the relationship between ethnicity/race and OA-related pain, disability, and functional impairment at baseline and during a 2-year follow-up period in non-Hispanic Black and non-Hispanic White adults with knee pain. These results point to the need for interventions that target pain catastrophizing.

Coronal and axial alignment relationship in Caucasian patients with osteoarthritis of the knee.

Individualized pre-operative assessment of the patterns of the lower extremity anatomy and deformities in patients undergoing total knee arthroplasty seems essential for a successful surgery. In the present study, we investigated the relationship among the coronal alignment and the rotational profile of the lower extremities in the Caucasian population with end-stage knee osteoarthritis. We conducted a prospective study of 385 knees that underwent a pre-operative three-dimensional computed tomography-based model. The lower extremity alignment was determined (mechanical tibiofemoral or hip-knee-ankle angle, supplementary angle of the femoral lateral distal angle, and proximal medial tibial angle). For each case, the femoral distal rotation (condylar twist angle), the femoral proximal version, and the tibial torsion were determined. As the coronal alignment changed from varus to valgus, the femoral external rotation increased (r = 0.217; p < 0.0005). As the coronal alignment changed from varus to valgus, the external tibial torsion increased (r = 0.248; p < 0.0005). No correlation was found between the global coronal alignment and the femoral version. The present study demonstrates a linear relationship between the coronal alignment and the rotational geometry of the distal femur. This correlation also occurs with the tibial torsion. Perhaps outcomes of total knee arthroplasty surgery might be improved by addressing these deformities as well.

Patterns and Correlates of Self-Management Strategies for Osteoarthritis-Related Pain Among Older Non-Hispanic Black and Non-Hispanic White Adults.

OBJECTIVE: Knee osteoarthritis (OA) is a leading source of pain and disability among older adults. Self-management (SM) strategies are recommended to manage OA symptoms. Sociodemographic and clinical characteristics, along with other factors, may influence SM utilization rate. This study sought to examine the prevalence and correlates of SM use for pain among non-Hispanic Black patients (NHB) and non-Hispanic White patients (NHW) older adults with or at risk for knee OA. METHODS: A secondary data analysis was conducted on the Understanding Pain and Limitations in Osteoarthritic Disease multisite observational study, which included NHB (n = 104) and NHW (n = 98) community-dwelling older adults with or at risk for knee OA. Participants completed measures of sociodemographics, pain SM use, coping, and clinical and experimental pain. RESULTS: Clinical and experimental pain were significantly greater among NHBs compared to NHWs. There were no significant differences in use of total SM by ethnicity/race. Interestingly, multiple linear regression revealed that clinical and experimental pain indices, as well as coping, number of pain sites, age, and sex were differentially associated with total SM use between NHBs and NHWs. There were significant ethnicity/race by type of pain management interaction effects for pain measures. CONCLUSION: SM is common among older adults with or at risk for knee OA pain, and the prevalence of SM does not differ by ethnicity/race, but many guideline-recommended interventions for OA are underutilized. Importantly, different factors were associated with the use of SM, highlighting distinct biopsychosocial mechanisms contributing to SM use in NHBs and NHWs.

Cumulative Disadvantage and Disparities in Depression and Pain Among Veterans With Osteoarthritis: The Role of Perceived Discrimination.

OBJECTIVE: Perceived discrimination is associated with chronic pain and depression and contributes to racial health disparities. In a cohort of older adult veterans with osteoarthritis (OA), our objective was to examine how membership in multiple socially disadvantaged groups (cumulative disadvantage) was associated with perceived discrimination, pain, and depression. We also tested whether perceived discrimination mediated the association of cumulative disadvantage with depression and pain. METHODS: We analyzed baseline data from 270 African American veterans and 247 White veterans enrolled in a randomized controlled trial testing a psychological intervention for chronic pain at 2 Department of Veterans Affairs medical centers. Participants were age ≥50 years and self-reported symptomatic knee OA. Measures included the Everyday Discrimination Scale, the Patient Health Questionnaire Depression Scale, the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale, and demographic variables. Cumulative disadvantage was defined as the number of socially disadvantaged groups to which each participant belonged (i.e., self-reported female sex, African American race, annual income of <$20,000, and/or unemployed due to disability). We used linear regression models and Sobel's test of mediation to examine hypotheses. RESULTS: The mean ± SD number of social disadvantages was 1.3 ± 1.0. Cumulative disadvantage was significantly associated with higher perceived discrimination, pain, and depression (P < 0.001 for all). Perceived discrimination significantly mediated the association between cumulative disadvantage and depression symptoms (Z = 3.75, P < 0.001) as well as pain severity (Z = 2.24, P = 0.025). CONCLUSION: Perceived discrimination is an important psychosocial stressor that contributes to worsening OA-related mental and physical health outcomes, with greater effects among those from multiple socially disadvantaged groups.

Association of rs2862851 in TGFA Gene with Peripheral TGFA Levels and the Severity of Knee Osteoarthritis in the Han Chinese Population.

Background: Osteoarthritis (OA) is a complex joint disorder characterized by sclerosis of subchondral bone. The knee is one of the most commonly affected joints. Given that the genetic mechanisms underlying knee OA remain elusive, our study aims were to first confirm the association of the TGFA gene alleles with the risk of knee OA and, second, to evaluate the relationship between peripheral TGFA concentrations and knee OA in an independent Han Chinese population. Materials and Methods: We performed a case-control study consisting of 392 knee OA patients and 808 unrelated healthy controls. Single-marker-based association analyses and haplotype-based analyses using 3 single nucleotide polymorphisms (SNPs) were performed to confirm the association of TGFA gene alleles with the risk of knee OA. Furthermore, we used enzyme-linked immunosorbent assay (ELISA) kits to detect the peripheral blood TGFA concentrations in patients and healthy controls and then evaluated the relationships between the TGFA alleles and genotypes with serum TGFA levels. Results: We replicated the genetic association of the rs2862851 T allele with the risk of knee OA (p = 1.68 × 10-4, OR = 1.41). Moreover, we observed that the peripheral TGFA concentrations were higher in knee OA patients than in healthy controls (p = 8.15 × 10-13). The peripheral TGFA concentrations were significantly different among the various rs2862851 genotypes for both cases (p = 4.16 × 10-16) and controls (p = 7.24 × 10-19). The individuals with the TT genotype in both cases and controls, had the highest peripheral TGFA concentrations. Moreover, with the increase in knee OA grade, peripheral TGFA concentration also increased (p = 1.36 × 10-72). Conclusion: Our study confirmed the association of the TGFA gene with the risk of knee OA and identified a positive correlation between peripheral TGFA levels and the severity of knee OA in the Han Chinese population, providing clues for understanding the etiology of knee OA.

The IL-6 rs12700386 polymorphism is associated with an increased risk of developing osteoarthritis in the knee in the Chinese Han population: a case-control study.

BACKGROUND: This case-control study aims to examine the association between the Interleukin-6 (IL-6) rs12700386 polymorphism and the increased risk of developing osteoarthritis (OA) in the knee in the Chinese Han population. METHODS: We extracted DNA from 763 subjects (352 OA patients and 411 healthy controls). The relative expression levels of IL-6 in blood samples of patients with knee OA was determined by quantitative reverse transcription PCR (qRT-PCR) and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used for genotyping the IL-6 gene polymorphism. RESULTS: We found that the IL-6 polymorphism rs12700386 enhanced patient susceptibility to developing knee OA. Based on a subgroup analysis, the risk of developing knee OA was elevated in smokers, drinkers, and subjects ≥55 years old or with BMI ≥ 25 kg/m2. The combination of smoking, drinking, and having the rs12700386 genotype led to an increase in the risk of developing knee OA, indicating that an underlying interaction between gene and environment exists. The rs12700386 genotype was found to be correlated with an increase in IL-6 expression. We also found that IL-6 levels were significantly higher in the CC genotype compared to the GG genotype carriers in OA patients. CONCLUSION: These data suggest that the rs12700386 polymorphism in the IL-6 gene leads to an increase in the risk of knee OA in Chinese Han individuals.

Evaluation of relationship between DNA methyltransferase 3 ß gene and the risk of hip osteoarthritis: A case-control study based on a Han Chinese population.

AIM: Osteoarthritis (OA) is a chronic degenerative joint disease. Early studies have indicated that genetic and environmental factors contribute to the risk of OA. However, the etiology of OA remains unknown. Our study aimed to evaluate the association of DNMT3B gene with the risk of hip OA in Han Chinese individuals. METHODS: A total of 2070 subjects were recruited into the study, including 658 patients with hip OA and 1412 healthy controls. Twelve tag single nucleotide polymorphisms (SNPs) were selected and genotyped in our samples. Genetic associations between DNMT3B gene and the risk of hip OA were examined at both the single marker and haplotype levels. Cis-expression quantitative trait loci signals that achieve genome-wide significance of targeted SNPs from multiple types of human tissues were extracted from the GTEx database. RESULTS: Significant signals were identified for SNP rs2424905 in 4 genetic models. The T allele was significantly associated with an increased risk of hip OA (odds ratio = 1.53; 95% CI = 1.28-1.83). The T allele was also significantly associated with higher Kellgren-Lawrence grade in the patients with hip OA (χ2  = 32.70, P = 1.37 × 10-6 ). Moreover, SNP rs2424905 was significantly associated with the gene expression level of multiple genes, including DNMT3B, C20orf203, COMMD7, EFCAB8, MAPRE1, and RP5-1085F17.3, from several types of human tissues. CONCLUSION: Our results indicated that rs2424905 of DNMT3B gene contributed to the risk of hip OA and its clinical severity in a Han Chinese population. These findings suggested that rs2424905 of DNMT3B could be a promising genetic marker to assess susceptibility to hip OA in Han Chinese populations.

Cross-cultural translation and validation of the Chinese Oxford Knee Score and the Activity and Participation Questionnaire.

OBJECTIVE: To cross-culturally translate and validate the Chinese versions of the Oxford Knee Score (OKS) and the Activity and Participation Questionnaire (APQ) in patients with end-stage knee osteoarthritis who are also candidates for knee replacement. METHODS: The Chinese version of the OKS and APQ was completed by standard forward-backward translation and adaption. The feasibility was validated by a pretest in 30 patients. The final version together with the Short Form-36 (SF-36), EQ-5D, and EQ visual analog scale were assessed in 150 patients, and the OKS and APQ were repeated in 30 patients after a 2-week interval. The psychometric properties of the OKS and APQ were evaluated for test-retest reliability using intraclass correlation coefficients (ICCs), internal consistency using Cronbach's α, and construct validity using Spearman's correlation analysis. RESULTS: All patients were able to understand and complete both the OKS and APQ without difficulty (i.e. no missing data). The ICCs were 0.959 for the OKS, 0.956 for the APQ for total scores, and >0.7 for each item. Cronbach's α was greater than 0.7, and the corrected item-total correlation was greater than 0.4 for each item of both questionnaires. The OKS and APQ showed better correlations with questions from the pain and function domains than with those from the mental status domains of the SF-36 and EQ-5D. No floor or ceiling effect was identified in either questionnaire. CONCLUSIONS: The Chinese versions of the OKS and APQ are easy to understand and complete and showed good reliability and validity. They can be used to assess patient-reported outcomes after undergoing knee replacement in mainland China.

Genetic estrogen receptor alpha gene PvuII polymorphism in susceptibility to knee osteoarthritis in a Chinese Han population: A southern Jiangsu study.

BACKGROUND: Knee osteoarthritis (KOA) is the most prevalent type of arthritis and genetic factors play an important role in KOA pathogenesis. Some studies have reported the association of estrogen receptor alpha (ESRα) gene polymorphism and KOA susceptibility in different populations. This study was designed to verify whether ESRα gene polymorphism (rs2234693) was associated with primary KOA in a Chinese Han population living in the south of Jiangsu. METHODS: A case-control association study on single nucleotide polymorphism (SNP) rs2234693 was performed, and a total of 1953 subjects (1033 OA cases and 920 controls) were genotyped. Allele and genotype frequencies were compared between KOA cases and control participants. RESULTS: SNP rs2234693 was significantly associated with KOA in the dominant genetic model (TT + TC vs. CC) in all the subjects (odds ratio (OR) = 1.30; 95% confidence interval (CI) = 1.02-1.66; P = .03), and T allele frequency was also higher compared with allele C (OR = 1.38; 95% CI = 1.06-1.80; P = .02). After stratification by gender, there was no evident difference between the two groups in female and male subjects (P > .05). With a stratification for KOA severity, the combined genotype (TT + TC) (OR = 1.47; 95% CI = 1.12-1.94; P < .01) and T allele (OR = 1.61; 95% CI = 1.19-2.19; P < .01) were evidently associated with mild KOA, but not with severe KOA. CONCLUSIONS: ESRα gene is of considerable importance in the pathogenesis of early-stage KOA in a Chinese Han population living in southern Jiangsu.

The Unequal Effect of Income on Risk of Overweight/Obesity of Whites and Blacks with Knee Osteoarthritis: the Osteoarthritis Initiative.

BACKGROUND: Although the protective effect of socioeconomic status (SES) against risk of overweight/obesity is well established, such effects may not be equal across diverse racial and ethnic groups, as suggested by the marginalization-related diminished returns (MDR) theory. AIMS: Built on the MDR theory, this study explored racial variation in the protective effect of income against overweight/obesity of Whites and Blacks with knee osteoarthritis (OA). METHODS: This cross-sectional study used baseline data of the OA Initiative, a national study of knee OA in the USA. This analysis included 4664 adults with knee OA, which was composed of 3790 White and 874 Black individuals. Annual income was the independent variable. Overweight/obesity status (body mass index more than 25 kg/m2) was the dependent variable. Race was the moderator. Logistic regressions were used for data analysis. RESULTS: Overall, higher income was associated with lower odds of being overweight/obese. Race and income showed a statistically significant interaction on overweight/obesity status, indicating smaller protective effect of income for Blacks compared with Whites with knee OA. Race-stratified regression models revealed an inverse association between income and overweight/obesity for White but not Black patients. CONCLUSIONS: While higher income protects Whites with knee OA against overweight/obesity, this effect is absent for Blacks with knee OA. Clinicians should not assume that the needs of high-income Whites and Blacks with knee OA are similar, as high-income Blacks may have greater unmet needs than high-income Whites. Racially tailored programs may help reduce the health disparities between Whites and Blacks with knee OA. The results are important given that elimination of racial disparities in obesity is a step toward eliminating racial gap in the burden of knee OA. This is particularly important given that overweight/obesity is not only a prognostic factor for OA but also a risk factor for cardiometabolic diseases and premature mortality.

Potential Role of Cost and Quality of Life in Treatment Decisions for Arthritis-Related Knee Pain in African American and Latina Women.

OBJECTIVE: The present study was undertaken to investigate whether Latina and African American women with arthritis-related knee pain and primary care providers who treat them believe their treatment decisions would benefit from having more information about the impact of treatment on their quality of life, medical care costs, and work productivity. METHODS: We conducted 4 focus groups of Latina and African American women over age 45 years who had knee pain. We also conducted 2 focus groups with primary care providers who treated Latina and African American women for knee pain. The participants were recruited from the community. They were asked their opinions about a decision tool that presented information on a range of treatment options and their impacts on quality of life, medical care costs, and work productivity. They were asked whether providing this information would help them make better treatment decisions. We analyzed the focus group transcripts using ATLAS.ti. RESULTS: We found that minority women and primary care providers endorsed the use of a decision-making tool that provided information of the impact of treatment on quality of life, medical care costs, and work productivity. Providers felt that patients would benefit from having the additional information but were concerned about its complexity and some patients' ability to comprehend the information. CONCLUSION: Latina and African American women could make more informed treatment decisions for their knee pain using a decision-making tool that provides them with significant information about how various treatment options may impact their quality of life, medical care costs, and workforce productivity.

Nonsteroidal Anti-Inflammatory Drug Use in Chronic Arthritis Pain: Variations by Ethnicity.

PURPOSE: Our objective was to determine if there are ethnic differences in the use of over-the-counter (OTC) and prescription oral nonsteroidal anti-inflammatory drugs (NSAIDs) and if observed ethnic differences persist after adjustment for sociodemographic and clinical factors. METHODS: Knee and hip osteoarthritis study participants were identified. Surveys were administered to collect sociodemographics, clinical information, and oral treatment methods for arthritis. Multivariable logistic regression models were created using a fully conditional method. RESULTS: Hispanics (n = 130), compared to non-Hispanic whites (n = 204), were less likely to have a high school education (26.9% vs 63.2%, P <0.001), less likely to have private medical insurance (P <0.001), and more likely to have worse health (P = 0.004). OTC oral NSAID use was less common (52.9% vs 66.3%, P = 0.019), whereas prescription oral NSAID use was more common (43.4% vs 31.7%, P = 0.042) among Hispanics than non-Hispanic whites in the last 6 months. The ethnic difference in using an OTC NSAID instead of not using any oral NSAID was attenuated and no longer significant when adjusted for age, sex, education, and medical insurance (odds ratio [OR] 0.54 [95% confidence interval [CI]: 0.28-1.02]). The odds of using a prescription instead of an OTC NSAID remained significantly higher among Hispanics than non-Hispanic whites when adjusted for the same variables (odds ratio 2.17 [95% confidence interval: 1.16-4.05]). CONCLUSIONS: Among patients with osteoarthritis, OTC NSAIDs were less commonly used but prescription NSAIDs were more commonly used by Hispanics than non-Hispanic whites. Sociodemographic factors partially mediate ethnic differences in the use of oral NSAIDs.

Geographical and ethnic differences of osteoarthritis-associated hip and knee replacement surgeries in New Zealand: a population-based cross-sectional study.

OBJECTIVES: To (1) explore the regional and ethnic differences in rates of publicly funded osteoarthritis-associated hip and knee replacement surgeries and (2) investigate the mortality after surgery. DESIGN: Population-based, retrospective, cross-sectional study. SETTING: General population in New Zealand. PARTICIPANTS: Patients with osteoarthritis who underwent publicly funded primary hip and knee replacement surgeries in 2005-2017. Patients aged 14-99 years were included. PRIMARY AND SECONDARY OUTCOME MEASURES: Age-standardised rate, standardised mortality ratio (SMR) and 30 days, 90 days and 1 year mortality. RESULTS: We identified 53 439 primary hip replacements and 50 072 primary knee replacements with a diagnosis of osteoarthritis. The number and age-standardised rates of hip and knee replacements increased over time. Maori had the highest age-standardised rate of hip replacements, followed by European/others and Pacific, and Asian had the lowest rate. Pacific had the highest age-standardised rate of knee replacements, followed by Maori and European/others, and Asian had the lowest rate. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. The SMRs of patients undergoing hip and knee replacements were lower than the general population: 0.92 (95% CI 0.89 to 0.95) for hip and 0.79 (95% CI 0.76 to 0.82) for knee. The SMRs were decreasing over time. The patterns of 30 days, 90 days and 1 year mortality were similar to the SMR. CONCLUSIONS: The numbers of publicly funded osteoarthritis-associated primary hip and knee replacements are steadily increasing. Maori people had the highest age-standardised rate of hip replacements and Pacific people had the highest rate of knee replacements. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. Compared with the general population, patients who had hip and knee replacements have a better life expectancy.

Knee osteoarthritis risk in non-industrial societies undergoing an energy balance transition: evidence from the indigenous Tarahumara of Mexico.

Non-industrial societies with low energy balance levels are expected to be less vulnerable than industrial societies to diseases associated with obesity including knee osteoarthritis. However, as non-industrial societies undergo rapid lifestyle changes that promote positive energy balance, individuals whose metabolisms are adapted to energetic scarcity are encountering greater energy abundance, increasing their propensity to accumulate abdominal adipose tissue and thus potentially their sensitivity to obesity-related diseases. OBJECTIVES: Here, we propose that knee osteoarthritis is one such disease for which susceptibility is amplified by this energy balance transition. METHODS: Support for our hypothesis comes from comparisons of knee radiographs, knee pain and anthropometry among men aged ≥40 years in two populations: Tarahumara subsistence farmers in Mexico undergoing the energy balance transition and urban Americans from Framingham, Massachusetts. RESULTS: We show that despite having markedly lower obesity levels than the Americans, the Tarahumara appear predisposed to accrue greater abdominal adiposity (ie, larger abdomens) for a given body weight, and are more vulnerable to radiographic and symptomatic knee osteoarthritis at lower levels of body mass index. Also, proportionate increases in abdomen size in the two groups are associated with greater increases in radiographic knee osteoarthritis risk among the Tarahumara than the Americans, implying that the abdominal adipose tissue of the Tarahumara is a more potent stimulus for knee degeneration. CONCLUSIONS: Heightened vulnerability to knee osteoarthritis among non-industrial societies experiencing rapid lifestyle changes is a concern that warrants further investigation since such groups represent a large but understudied fraction of the global population.

At the Intersection of Ethnicity/Race and Poverty: Knee Pain and Physical Function.

BACKGROUND: Knee osteoarthritis (OA) disproportionately affects racial and ethnic minorities. Non-Hispanic Blacks (NHB) report a higher prevalence and severity of knee OA symptoms than their non-Hispanic White (NHW) counterparts. The role of poverty in explaining this disparity remains unclear. OBJECTIVE: The overall aim of this cross-sectional study was to determine whether ethnic/racial differences in knee pain and physical function varied according to poverty status. DESIGN: NHB and NHW adults with or at risk of knee OA self-reported sociodemographic information, and completed the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) and the Short Physical Performance Battery (SPPB). Annual income was adjusted for number of household occupants to determine poverty status (i.e., living above versus below poverty line). RESULTS: Findings revealed 120 individuals living above the poverty line (49% NHB, 77% NHW) and 71 individuals living below the poverty line (51% NHB, 23% NHW). Adjusted multivariable models revealed significant ethnic/race by poverty status interactions for knee pain (p = 0.036) and physical function (p = 0.032) on the WOMAC, as well as physical function on the SPPB (p = 0.042). Post hoc contrasts generally revealed that NHW adults living above the poverty line experienced the least severe knee pain and best physical function, while NHB adults living below the poverty line experienced the most severe knee pain and poorest physical function. CONCLUSIONS: Results of the present study add to the literature by emphasizing the importance of considering poverty and/or other indicators of socioeconomic status in studies examining ethnic/racial disparities in pain and physical function.

Preoperative Patient Factors Affecting Length of Stay following Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Total knee arthroplasty (TKA) yields substantial improvements in quality of life for patients with severe osteoarthritis. Previous research has shown that TKA outcomes are inferior in patients with certain demographic and clinical factors. Length of stay (LOS) following TKA is a major component of costs incurred by healthcare providers. It is hypothesized that patient-related factors may influence LOS following TKA. The purpose of this systematic review and meta-analysis is to investigate these factors. METHODS: Three databases (PubMed, Embase, and OVID Medline) were searched using variants of the terms "total knee arthroplasty" and "length of stay". Studies were screened and data abstracted in duplicate. The primary outcome was the effect of prognostic variables on LOS following TKA. Meta-analysis was performed using the Review Manager (RevMan) software (version 5.3. Copenhagen: The Nordic Cochrane Center, The Cochrane Collaboration, 2014). RESULTS: A total of 68 studies met all inclusion criteria for this review. These studies comprised 21,494,459 patients undergoing TKA with mean age 66.82 years (range, 15-95 years) and 63.8% (12,165,160 of 19,060,572 reported) females. The mean MINORS score was 7, suggesting that studies had a low quality of evidence. Mean LOS following TKA has steadily decreased over the past 4 decades, partially because of the implementation of fast-track programs. Demographic factors associated with increased LOS were age >70 years (mean difference [MD] = 0.81; 95% confidence interval [CI] = 0.38-1.24), female gender (MD = 0.32; 95% CI = 0.29-0.48), body mass index >30 (MD = 0.09; 95% CI = 0.01-0.16), and non-White race (MD = 0.20; 95% CI = 0.10-0.29). Clinical factors associated with increased LOS were American Society of Anesthesiologists score 3-4 vs 1-2 (MD = 1.12; 95% CI = 0.58 to 1.66), Charlson Comorbidity Index > 0 vs 0 (MD = 0.77; 95% CI = 0.32 to 1.22), and preoperative hemoglobin < 130 g/L (MD = 0.66; 95% CI = 0.34 to 0.98). CONCLUSION: This systematic review and meta-analysis showed that increased age, female gender, body mass index ≥ 30, non-White race, American Society of Anesthesiologists > 2, Charlson Comorbidity Index > 0, and preoperative hemoglobin < 130 g/L were predictors of increased LOS. Mean LOS has steadily decreased over the past decades with the implementation of perioperative "fast-track" programs. Future research should investigate the benefits of preoperative risk factor modification on LOS, in addition to novel surgical approaches, anesthetic adjuvants, and physiotherapy modifications. LEVEL OF EVIDENCE: IV, systematic review, and meta-analysis of level III and IV evidence.