Increased Risk of New-Onset Rheumatoid Arthritis Among Osteoarthritis Patients Received Total Knee Arthroplasty: a global federated health network analysis.

Background: Complications of total knee arthroplasty (TKA) had been widely discussed. However, whether TKA influence risk of rheumatoid arthritis (RA) in osteoarthritis patients remained uncertain. We intend to evaluate the risk of RA in osteoarthritis patients underwent TKA. Methods: In this retrospective cohort study, data was retrieved from the US collaborative networks in TriNetX research network. Within the study period between 2005 and 2017, osteoarthritis patients underwent TKA were enrolled as case cohort whereas osteoarthritis patients never underwent TKA were enrolled as control cohort. Covariates were matched via propensity score matching. Risk of RA in TKA patients were valuated under various follow-up time and sensitivity models. Results: Under 1-year, 3-year and 5-year of follow-up, TKA patients were associated with significantly elevated risk of RA, especially under 1-year follow-up (HR=1.74; 95% CI, 1.39-2.18). Subgroup analysis demonstrated a significant increase in the risk of RA following TKA in the female subgroup (HR=1.42; 95% CI, 1.24-1.63), the subgroup aged 18-64 years (HR=1.48; 95% CI, 1.11-1.97), and the subgroup aged greater than 65 years old (HR=1.38; 95% CI, 1.21-1.58) based on 5-year follow-up. Conclusion: Clinicians should be concerned about uncharted association between TKA and RA reported our current study. Additional prospective studies and in-depth mechanistic inquiries were warranted to determine the causation.

Early cartilage lesion and 5-year incident joint surgery in knee osteoarthritis patients: a retrospective cohort study.

OBJECTIVE: to investigate the association between cartilage lesion-related features observed in knee osteoarthritis (OA) patients' first MRI examination and incident knee surgery within 5 years. Additionally, to assess the predictive value of these features for the incident knee surgery. METHODS: We identified patients diagnosed with knee OA and treated at our institution between January 2015 and January 2018, and retrieved their baseline clinical data and first MRI examination films from the information system. Next, we proceeded to determine joint space narrowing grade, cartilage lesion size grade, cartilage full-thickness loss grade and cartilage lesion sum score for the medial and lateral compartments, respectively. Generalized linear regression models examined the association of these features with 5-year incident knee surgery. Positive and negative predictive values (PPVs and NPVs) were determined referring to 5-year incident knee surgery. RESULTS: Totally, 878 participants (knees) were found eligible to form the study population. Within the 5 years, surgery was performed on 61 knees. None of the cartilage-related features had been found significantly associated with incident surgery. The results were similar for medial and lateral compartments. The PPVs were low for all the features. CONCLUSIONS: Among symptomatic clinically diagnosed OA knees, cartilage lesions observed in the first MRI examinations were not found to be associated with the occurrence of joint surgery within a 5-year period. All these cartilage-related features appear to have no additional value in predicting 5-year incident joint surgery.

Burden evaluation and prediction of osteoarthritis and site-specific osteoarthritis coupled with attributable risk factors in China from 1990 to 2030.

OBJECTIVE: This study aimed to estimate and predict the burden of osteoarthritis (OA) and site-specific OA (hip, knee, hand, and others) from 1990 to 2030 and their attributable risk factors in China. METHOD: Data were obtained from the Global Burden of Diseases 2019. The burden was estimated by analyzing the trends of prevalence, incidence, and disability-adjusted life years (DALY). Population attributable risk (PAR) was calculated to assess the impact of high body mass index (BMI). The prediction from 2020 to 2030 was implemented by Bayesian age-period-cohort analysis. RESULTS: In China, prevalent cases, DALY, and incident cases of OA increased to 132.81 million, 4.72 million, and 10.68 million, respectively. Age-standardized rates (ASRs) of prevalence, DALYs, and incidence increased for OA and site-specific OA, especially for hip OA. Site-specific OA showed different susceptible peaking ages, and the burden for those over 50 years old became serious. Female preference existed in the trends for knee OA but not in those for hip, hand, and other OA. PARs of high BMI continued to increase, impacting knee OA more than hip OA and showing female preference. In the next decade, incident cases for OA and site-specific OA will continue to increase, despite that the ASR of OA incidence will decrease. CONCLUSIONS: OA and site-specific OA remain huge public health challenges in China. The burden of OA and site-specific OA is increasing, especially among people over 50 years old. Health education, exercise, and removing modifiable risk factors contribute to alleviate the growing burden. Key Points • In China, the burden of osteoarthritis and site-specific osteoarthritis (hip, knee, hand, and others) as well as the Risk Factor (high body mass index) increased greatly from 1990 to 2019. • It is estimated that incident cases for OA and site-specific OA will continue to increase, despite that the ASR of OA incidence will decrease.

Clinical phenotypes of comorbidities in end-stage knee osteoarthritis: a cluster analysis.

OBJECTIVES: Comorbidities, as components of these heterogeneous features, often coexist with knee osteoarthritis, and are particularly prevalent in end-stage knee osteoarthritis. Here, we attempted to identify the different clinical phenotypes of comorbidities in patients with end-stage knee osteoarthritis by cluster analysis. METHODS: A total of 421 inpatients diagnosed with end-stage knee osteoarthritis who underwent inpatient surgery were included in this cross-sectional study. 23 demographic, comorbidity, inflammatory immune and evaluation scale variables were collected. Systematic clustering after factor analysis and separate two-step cluster analysis were performed for individual comorbidity variables and all variables, respectively, to objectively identify the different clinical phenotypes of the study patients. RESULTS: Four clusters were finally identified. Cluster 1 had the largest proportion of obese patients (93.8%) and hypertension was common (71.2%). Almost all patients in cluster 2 were depressed (95.8%) and anxiety disorders (94.7%). Cluster 3 combined patients with isolated end-stage knee osteoarthritis and a few comorbidities. Cluster 4 had the highest proportion of patients with rheumatoid arthritis (58.8%). CONCLUSIONS: Patients with end-stage knee osteoarthritis may be classified into four different clinical phenotypes: "isolated end-stage knee osteoarthritis"; "obesity + hypertension"; "depression + anxiety"; and "rheumatoid arthritis", which may help guide individualized patient care and treatment strategies.

Radiographic knee osteoarthritis severity has no impact on fall risk: the locomotive syndrome and health outcomes in the aizu cohort study (LOHAS): a cross-sectional study.

BACKGROUND: To investigate factors that have an impact on the risk of falls and determine whether radiographic knee osteoarthritis (KOA) is a factor involved in falls independent of knee pain, psychological factors, and physical function. METHODS: A cross-sectional analysis was conducted on 1083 subjects for the 2009 Locomotive Syndrome and Health Outcomes in the Aizu Cohort Study (LOHAS). A logistic regression analysis was performed to examine the relationship between radiographic KOA and fall history. RESULTS: Fall history was significantly associated with the severity of knee pain. Compared to subjects with no knee pain, the odds ratio (OR) was 1.53 times higher in the subjects with mild knee pain (95% confidence interval [CI]: 1.04-2.25), 1.69 times higher in those with moderate knee pain (95%CI: 1.03-2.79), and 2.98 times higher in those with severe knee pain (95%CI: 1.67-5.30). In subjects with depression, the OR was 1.91 (95%CI: 1.25-2.92), and in those with decreased mobility, the OR was 1.70 (95%CI: 1.08-2.69). Age, gender, knee crepitus, BMI, OLST, and sleeping pill use were not significantly associated with fall risk. In a multivariate analysis, radiographic KOA severity was not significantly associated with fall risk (OR 0.81, 95%CI 0.44-1.50 in mild OA; OR 1.10, 95%CI 0.57-2.14 in severe OA). CONCLUSION: Knee pain, decreased mobility, and depression, but not the radiographic KOA severity, were significantly associated with a fall risk. Regardless of the individual's radiographic KOA severity, the risk of falls may be reduced by treating his/her knee pain, mobility problems, and/or psychological factors.

Causal analysis of body composition measurements in osteoarthritis knee: a two-sample mendelian randomization study.

BACKGROUND: To analyse the causal associations of different physical measures with osteoarthritis knee (KOA). METHODS: Exposure factors (weight, body mass index (BMI), body fat percentage, waist circumference, hip circumference, waist-hip ratio (WHR), and basal metabolic rate (BMR)), and outcome factor KOA were analyzed by inverse-variance weighted (IVW) method, along with heterogeneity test, sensitivity and pleiotropy analyses. Meta-analysis was used to combine the effect values of IVW methods in different data sources. RESULTS: Weight, BMI, body fat percentage, waist circumference, hip circumference and BMR analyses showed causal association with increased KOA risk, while WHR analysis indicated a reduction of the incidence of KOA. P-value for all the results was less than 0.05 and F-value large than 20. All results were negative for heterogeneity tests and sensitivity analyses, and there was pleiotropy in weight and BMR. Meta-analysis results showed that the results of Odds Ratios (95% Confidence Intervals) for Weight (1.43(1.35-1.51)), BMI (1.40(1.10-1.78)), body fat percentage (1.56(1.44-1.68)), waist circumference (1.40(1.10-1.78)), hip circumference (1.37(1.30-1.44)), WHR (0.86(0.71-1.04)) and BMR (1.36(1.27-1.46) were consistent with the ones by Mendelian randomization analyses. CONCLUSIONS: Body fat percentage may be a better indicator of KOA than BMI. In addition, weight and BMR may have a causal effect in KOA, but WHR does not have a causal relationship. BMI, body fat percentage, waist circumference, and hip circumference has a causal effect on KOA.

Weight-Bearing Physical Activity, Lower-Limb Muscle Mass, and Risk of Knee Osteoarthritis.

Importance: It has been demonstrated that total physical activity is not associated with risk of osteoarthritis. However, the association of different types of physical activity with incident knee osteoarthritis remains unclear. Objective: To determine whether weight-bearing recreational physical activities are associated with increased risk of incident knee osteoarthritis. Design, Setting, and Participants: This prospective cohort study used data from the Rotterdam Study (1996 to 2009), including participants with knee x-ray measurements at baseline and follow-up examinations. Participants with knee osteoarthritis at baseline were excluded. Residents aged 45 years and older of the Ommoord district in the city of Rotterdam in The Netherlands were invited to join the Rotterdam Study (78% response rate). Analysis was conducted in June 2023. Exposure: Total, weight-bearing, and non-weight-bearing recreational physical activities collected by questionnaires at baseline. Main Outcomes and Measures: Incident radiographic knee osteoarthritis measured by knee x-ray was the primary outcome, and incident symptomatic knee osteoarthritis defined by x-ray and knee pain questionnaire was the secondary outcome. The association of different types of recreational physical activity with radiographic knee osteoarthritis was examined using logistic regression within generalized estimating equation framework after adjusting for potential confounders. A prespecified stratification analysis was planned on the basis of lower-limb muscle mass index (LMI) tertiles, measured by dual-energy x-ray absorptiometry. Results: A total of 5003 individuals (2804 women [56.0%]; mean [SD] age, 64.5 [7.9] years) were included. The knee osteoarthritis incident rate was 8.4% (793 of 9483 knees) for a mean (SD) follow-up time of 6.33 (2.46) years. Higher weight-bearing activity was associated with increased odds of incident knee osteoarthritis (odds ratio [OR], 1.22; 95% CI, 1.10-1.35; P < .001), but non-weight-bearing activity was not (OR, 1.04; 95% CI, 0.95-1.15; P = .37). In the analysis stratified by LMI tertiles, the association of weight-bearing activity with incident osteoarthritis was found only among 431 patients in the lowest LMI tertile (OR, 1.53; 95% CI, 1.15-2.04; P = .003), but not among patients in the middle or high LMI tertile. Conclusions and Relevance: The findings of this study suggest that weight-bearing activity is associated with incident knee osteoarthritis in people with low levels of lower-limb muscle mass, which might be a promising avenue for tailored advice for physical activity.

Prevalence and Risk Factors of Osteoarthritis in Korea: A Cross-Sectional Study.

Background and Objectives: The goal of this study is to determine the prevalence of knee osteoarthritis (OA) and risk factors for the disease in Korean adults over the age of 50, as well as to provide basic data for OA prevention through management. Materials and Methods: Based on 2010-2013 data from the Korean National Health and Nutrition Survey, 7962 adults over the age of 50 who participated in radiological tests and health surveys for the diagnosis of osteoarthritis were chosen as participants. Results: The risk factors for OA occurrence were investigated using complex sample multiple logistic regression analysis. According to the findings, the prevalence of knee OA in Korea was 33.3% in this study, with the risk of OA being higher in women, the elderly, people with a lower education level, and people with obesity. Conclusions: To reduce the incidence of OA, interventions and lifestyle changes are needed to prevent the onset of disease in participants with risk factors for OA, such as older women, low education levels, and obesity.

Assessing the causal associations of different types of statins use and knee/hip osteoarthritis: A Mendelian randomization study.

OBJECTIVE: This study comprehensively evaluated the causal relationship between different types of statins use and knee/hip osteoarthritis (OA) using a two-sample and multivariate Mendelian randomization (MR) method. METHODS: MR analysis was conducted using publicly available summary statistics data from genome-wide association studies (GWAS) to assess the causal associations between total statins use (including specific types) and knee/hip OA. The primary analysis utilized the inverse variance-weighted (IVW) method, with sensitivity analysis conducted to assess robustness. Multivariable MR (MVMR) analysis adjusted for low-density lipoprotein cholesterol (LDL-C), intermediate-density lipoprotein cholesterol (IDL-C), high-density lipoprotein cholesterol (HDL-C), and body mass index (BMI). RESULTS: The MR analysis revealed a significant inverse association between genetically predicted total statins use and the risk of knee OA (OR = 0.950, 95%CI: 0.920-0.982, p = 0.002) as well as hip OA (OR = 0.932, 95%CI: 0.899-0.966, p <0.001). Furthermore, this study highlighted a reduced risk of knee/hip OA with the use of atorvastatin and simvastatin. Rosuvastatin use was associated with a decreased risk of hip OA but showed no association with knee OA. MVMR results indicated no correlation between exposure factors and outcomes after adjusting for LDL-C or IDL-C. HDL-C may not significantly contribute to statin-induced osteoarthritis, while BMI may play an important role. CONCLUSION: This study provides compelling evidence of the close relationship between statin use and a reduced risk of knee/hip OA, particularly with atorvastatin and simvastatin. LDL-C and IDL-C may mediate these effects. These findings have important implications for the clinical prevention and treatment of knee/hip OA.

Eligibility for knee arthroplasty is associated with increased risk of acquired hallux valgus - a Mendelian randomized study.

OBJECTIVE: Clinically, it has been found that patients undergoing knee replacement have a high incidence of concomitant hallux valgus. In this study, we analyzed whether patients with osteoarthritis who underwent surgery and those patient who did not have surgery had an increased risk of hallux valgus by Mendelian randomization and performed reverse causal analysis. DESIGN: Genomewide association study (GWAS) data for osteoarthritis, categorized by knee arthritis with joint replacement, knee arthritis without joint replacement, hip arthritis with joint replacement, and hip arthritis without joint replacement.And acquired hallux valgus were downloaded for Mendelian randomized studies. MR analysis was performed using inverse variance-weighted (IVW), weighted median, and MR-Egger methods. MR-egger regression, MR pleiotropic residuals and outliers (MR-presso), and Cochran's Q statistical methods were used to evaluate heterogeneity and pleiotropy. RESULTS: The IVW results indicate that, compared to healthy individuals, patients who meet the criteria for knee osteoarthritis joint replacement surgery have a significantly higher risk of acquired hallux valgus. There were no significant causal relationships found for the remaining results. No significant heterogeneity or multiplicity was observed in all the Mr analyses. CONCLUSION: Our study supports the increased risk of acquired hallux valgus in patients eligible for knee replacement. There is necessary for clinicians to be concerned about the hallux valgus status of patients undergoing knee arthroplasty.

Nutrition and movement to improve quality of life in patients with knee osteoarthritis: the NUMOQUA study protocol for a randomised controlled trial.

BACKGROUND: Osteoarthritis (OA) has long been considered as a degenerative disease of cartilage tissue resulting from bodily wear and tear. However, there is accumulating evidence that inflammation plays a key role in the pathogenesis of OA. In knee OA, the most common form of OA, exercise therapy as an effective component of early treatment addresses functional deficits, pain and inflammation. Since inflammation is critical for the development and progress of OA, anti-inflammatory therapies must be combined strategically. In the course of the NUMOQUA project, an anti-inflammatory therapeutic diet named 'Austrian Osteoarthritis Cuisine' was developed. It is based on the framework of the New Nordic Diet combined with the food-based dietary guidelines of Austria, the guidelines for OA, the Austrian food culture and the principles of a sustainable diet. The present study examines the implementation of the 'Austrian OA Cuisine' combined with the evidence-based training programme GLA:D® (Good Life with osteoArthritis in Denmark) in Austrian patients with knee OA and the effects on quality of life, nutritional and inflammatory status, as well as oxidative stress parameters. METHODS: A total of 60 participants aged 50 to 75 with knee OA will be included and randomly assigned either to the intervention group or the control group. All participants will undergo the GLA:D® programme in the first 6 weeks. Additionally, the intervention group will receive nutritional group training and individual nutritional counselling on the 'Austrian OA Cuisine' over 9 months. The control group will receive general information about a healthy lifestyle. Measurements at baseline and at 4 follow-up dates include nutritional, inflammatory and oxidative stress markers. Furthermore, anthropometric, behavioural and clinical data will be obtained. The recruitment process lasted from autumn 2022 to January 2024, followed by the intervention until October 2024. DISCUSSION: The prevalence of OA is expected to increase in the future due to ongoing demographic changes and rising obesity rates. The expected results will provide important evidence on whether this interdisciplinary therapeutic approach could be a new, cost-effective and sustainable strategy to address the disease process of OA without negative side effects. TRIAL REGISTRATION: ClinicalTrials.gov NCT05955300. Date of registration: 23rd of October 2023.

Role of bariatric surgery in reducing periprosthetic joint infections in total knee arthroplasty. A systematic review and meta-analysis.

BACKGROUND: Obesity represents an epidemic of rising numbers worldwide year after year. In the Orthopedic field, obesity is one of the major causes leading to osteoarthritis needing Total Joint Arthroplasty (TJA). Still, contextually, it represents one of the most significant risk factors for joint replacement complications and failures. So, bariatric Surgery (BS) is becoming a valuable option for weight control and mitigating obesity-related risk factors. This review of the literature and meta-analysis aims to evaluate periprosthetic joint infections (PJI) and surgical site infections (SSI) rates in patients who underwent TKA after BS compared to obese patients without BS. METHODS: Systematic review was performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines up to October 2023. We included longitudinal studies comparing obese patients who underwent total knee arthroplasty after bariatric surgery (study group) and obese patients who underwent TKA (control group). The surgical site infection and Periprosthetic joint infection rate were compared among groups using a meta-analytical approach. RESULTS: The online database and references investigation identified one hundred and twenty-five studies. PJI rate differed significantly among groups, (z = -21.8928, p < 0.0001), with a lower risk in the BS group (z = -10.3114, p < 0.0001), for SSI, instead, not statistically significance were recorded (z = -0.6784, p = 0.4975). CONCLUSIONS: The current Literature suggests that Bariatric Surgery can reduce infectious complications in TKA, leading to better outcomes and less related costs treating of knee osteoarthritis in obese patients.

The rs1477196 SNP of the FTO Gene is Associated with Primary Knee Osteoarthritis in a Female Population from Northern Mexico.

Background: Osteoarthritis is a frequent rheumatic disease. Some single-nucleotide polymorphisms of the gene associated with fat mass and obesity are associated with increased body mass index and knee osteoarthritis. Objective: The objective of this study was to analyze the association of single nucleotide polymorphism rs1477196 of the fat mass and obesity gene with primary knee osteoarthritis. Methods: This observational and cross-sectional study included 347 Mexican participants. We performed the genotypification analysis with TaqMan® probe C_2031262_10 for rs1477196 (Thermo Fisher Scientific). Multivariate analysis included covariables such as age, type 2 diabetes, obesity, and postmenopause. Results: Type 2 diabetes, obesity, and postmenopause were associated with primary knee osteoarthritis in female participants. We did not find an association between rs1477196 and obesity. In the codominant and dominant genetic models, rs1477196 was significantly associated with primary knee osteoarthritis only in the female group, including in the model adjusted by other covariables (odds ratio = 2.517; 1.035-6.123; p = 0.042 and odds ratio = 2.387; 1.054-5.407; p = 0.037, respectively). The interaction between rs1477196 and obesity was significantly associated with primary knee osteoarthritis in female participants (p = 0.039 and p = 0.043). Conclusions: Our findings suggest that the rs1477196 variant of the fat and obesity mass gene may be associated with the risk of primary knee osteoarthritis in women.

Contralateral knee osteoarthritis is a risk factor for ipsilateral knee osteoarthritis progressing: a case control study.

BACKGROUND: Knee osteoarthritis (KOA) is a highly disabling disease, and studying its progression is crucial. However, it is still unclear whether the progression of ipsilateral knee osteoarthritis is influenced by contralateral knee osteoarthritis. METHODS: Data were collected from the OAI database and divided into two study cohorts (right/left KOA cohort). Each cohort had a target knee (right/left knee) and was further divided into two groups (exposure/control group). The demographic data of both cohorts were balanced at baseline by propensity score matching (PSM), and the data included rating scale and radiographic and clinical data. After checking for balance in the matched variables, we then compared the differences between the two groups in each cohort. Our primary focus was on the minimum joint space width (mJSW) of the target knee, which was measured four years after baseline. The secondary outcome was the arthroplasty rate of the target knee within nine years. RESULTS: In this study, a total of 678 participants were enrolled and matched. After 1:1 PSM of the baseline demographic data, 98 participants in the right KOA cohort (RKOAC) were successfully matched, and 117 participants in the left KOA cohort (LKOAC) were successfully matched. Furthermore, the standardized mean difference (SMD) of the matched variables in both cohorts was less than 0.25. After analyzing the outcome metrics, we found that the target knee had a significantly lower mJSW in the fourth year after baseline and a significantly greater arthroplasty rate within nine years in the exposed group than in the control group. RKOAC: mJSW (exposure: 2.6(1.1 ~ 3.6) vs. control: 3.3(2.0 ~ 4.2), P < 0.05), arthroplasty rate (exposure: 14(14.3%) vs. control: 4(4.1%), P < 0.05); LKOAC: mJSW (exposure: 3.1(2 ~ 3.9) vs. control: 3.4(2.6 ~ 4.2), P < 0.05), arthroplasty rate (exposure: 16(13.7%) vs. control: 7(6%), P < 0.05). CONCLUSIONS: Patients with knee osteoarthritis experienced greater progression of osteoarthritis when the contralateral knee was also affected.

General anesthesia is not associated with dementia in older adults with osteoarthritis for hip/knee replacements, a national population-based nested case-control study.

BACKGROUND: Dementia is a prevalent neurological condition, yet the relationship between dementia and general anesthesia remains uncertain. The study aimed to explore the association between general anesthesia and dementia using a nationwide population-based database. METHODS: The study extracted data from Taiwan's national health insurance, which encompassed the records of one million insured residents. A total of 59,817 patients aged 65 years and above, diagnosed with osteoarthritis between 2002 and 2010, were included. Among these patients, 3277 individuals with an initial diagnosis of dementia between 2004 and 2013 were matched with non-dementia patients based on age, gender, and the date of osteoarthritis diagnosis. Following a 1:2 random matching, the case group included 2171 patients with dementia, while the control group consisted of 4342 patients without dementia. The data was analyzed using conditional and unconditional logistic regressions. RESULTS: No significant differences in the odds of dementia were found between individuals exposed to general and regional anesthesia during hip/knee replacement surgeries (OR = 1.11; 95%CI: 0.73-1.70), after adjusting for age, sex, and co-morbidities. Similarly, there were no significant differences in the odds of dementia based on different durations of anesthesia exposure (General: <2 h: OR = 0.91, 95%CI = 0.43-1.92; 2-4 h: OR = 1.21, 95%CI = 0.82-1.79; >4 h: OR = 0.39, 95%CI = 0.15-1.01; compared to no exposure. Regional: <2 h: OR = 1.18, 95%CI = 0.85-1.62; 2-4 h: OR = 0.9, 95%CI = 0.64-1.27; >4 h: OR = 0.55, 95%CI = 0.15-1.96; compared to no exposure). Likewise, no significant differences were observed in the odds of dementia based on the number of replacement surgeries (twice: OR = 0.74, 95%CI = 0.44-1.23, compared to once). CONCLUSION: Neither general anesthesia nor regional anesthesia in hip/knee surgery was associated with dementia. Different numbers and durations of anesthesia exposure showed no significant differences in the odds for dementia.

The common marmoset as a translational model of age-related osteoarthritis.

Age-related osteoarthritis (OA) is a degenerative joint disease characterized by pathological changes in nearly every intra- and peri-articular tissue that contributes to disability in older adults. Studying the etiology of age-related OA in humans is difficult due to an unpredictable onset and insidious nature. A barrier in developing OA modifying therapies is the lack of translational models that replicate human joint anatomy and age-related OA progression. The purpose of this study was to determine whether the common marmoset is a faithful model of human age-related knee OA. Semi-quantitative microCT scoring revealed greater radiographic OA in geriatric versus adult marmosets, and the age-related increase in OA prevalence was similar between marmosets and humans. Quantitative assessments indicate greater medial tibial cortical and trabecular bone thickness and heterogeneity in geriatric versus adult marmosets which is consistent with an age-related increase in focal subchondral bone sclerosis. Additionally, marmosets displayed an age-associated increase in synovitis and calcification of the meniscus and patella. Histological OA pathology in the medial tibial plateau was greater in geriatric versus adult marmosets driven by articular cartilage damage, proteoglycan loss, and altered chondrocyte cellularity. The age-associated increase in medial tibial cartilage OA pathology and meniscal calcification was greater in female versus male geriatric marmosets. Overall, marmosets largely replicate human OA as evident by similar 1) cartilage and skeletal morphology, 2) age-related progression in OA pathology, and 3) sex differences in OA pathology with increasing age. Collectively, these data suggest that the common marmoset is a highly translatable model of the naturally occurring, age-related OA seen in humans.

Sex Differences in Sarcopenia in Patients Undergoing Total Knee Arthroplasty for Advanced Knee Osteoarthritis.

Background and Objectives: The purpose of this study was to compare sex differences in the incidence of sarcopenia, demographic characteristics, and preoperative sarcopenic parameters in patients undergoing TKA for advanced knee osteoarthritis (OA). Moreover, we sought to compare patient-reported outcome measures (PROMs) and the predisposing factors after TKA in patients with sarcopenia by sex through subgroup analysis. Materials and Methods: From May 2020 to September 2022, a total of 892 patients who were evaluable for sarcopenia before primary TKA were enrolled. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 criteria. Patients were assessed according to the presence or absence of sarcopenia. After a two-to-one matched-pair analysis for subgroup analysis, 21 knees in men were matched with a corresponding number of knees in women (42), resulting in a total of 63 knees. PROMs were investigated using the Knee Injury and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, and the Short Form-12 physical and mental component summary scores. Moreover, the postoperative complications and predisposing factors for male sarcopenia were investigated. Results: The prevalence of sarcopenia was 10.9% (97/892), and the prevalence was higher in men (19.6%, 21/107) than in women (9.7%, 76/785). In subgroup analyses, male patients had significantly inferior PROMs up to 12 months after index surgery. Moreover, there was no significant difference in the systemic complications between the two groups. Multivariate binary logistic regression analysis indicated that alcohol consumption, smoking, and higher modified Charlson Comorbidity Index (mCCI) were predisposing factors for male patients with sarcopenia. The prevalence of sarcopenia was higher in male patients undergoing primary TKA. Conclusions: When compared with the propensity-matched female group, male patients had inferior PROMs up to 12 months postoperatively. Alcohol consumption, current smoker status, and higher mCCI were predisposing factors for sarcopenia in male patients with advanced knee OA.

Phenotypes of osteoarthritis-related knee pain and their transition over time: data from the osteoarthritis initiative.

BACKGROUND: Identification of knee osteoarthritis (OA) pain phenotypes, their transition patterns, and risk factors for worse phenotypes, may guide prognosis and targeted treatment; however, few studies have described them. We aimed to investigate different pain phenotypes, their transition patterns, and potential risk factors for worse pain phenotypes. METHODS: Utilizing data from the Osteoarthritis Initiative (OAI), pain severity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. We identified the activity-related pain phenotypes and estimated the transition probabilities of pain phenotypes from baseline to the 24-month using latent transition analysis. We examined the risk factors at baseline with the 24-month pain phenotypes and the transition of pain phenotypes. RESULTS: In 4796 participants, we identified four distinct knee pain phenotypes at both baseline and 24-month follow-up: no pain, mild pain during activity (Mild P-A), mild pain during both rest and activity (Mild P-R-A), and moderate pain during both rest and activity (Mod P-R-A). 82.9% knees with no pain at baseline stayed the same at 24-month follow-up, 17.1% progressed to worse pain phenotypes. Among "Mild P-A" at baseline, 32.0% converted to no-pain, 12.8% progressed to "Mild P-R-A", and 53.2% remained. Approximately 46.1% of "Mild P-R-A" and 54.5% of "Mod P-R-A" at baseline experienced remission by 24-month. Female, non-whites, participants with higher depression score, higher body mass index (BMI), higher Kellgren and Lawrence (KL) grade, and knee injury history were more likely to be in the worse pain phenotypes, while participants aged 65 years or older and with higher education were less likely to be in worse pain phenotypes at 24-month follow-up visit. Risk factors for greater transition probability to worse pain phenotypes at 24-month included being female, non-whites, participants with higher depression score, higher BMI, and higher KL grade. CONCLUSIONS: We identified four distinct knee pain phenotypes. While the pain phenotypes remained stable in the majority of knees over 24 months period, substantial proportion of knees switched to different pain phenotypes. Several socio-demographics as well as radiographic lesions at baseline are associated with worse pain phenotypes at 24-month follow-up visit and transition of pain phenotypes.

Mediating effect of lower extremity muscle on the relationship between obesity and osteoarthritis in middle-aged and elderly women in Korea: based on the 2009-2011 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: This study investigated whether the lower extremity muscle mass index (LMI) mediates the relationship between general obesity, central obesity, and knee osteoarthritis in middle-aged and elderly women in Korea. METHODS: Data of 2,843 women aged ≥50 years were collected from the Korean National Health and Nutrition Examination Survey conducted between 2009 and 2011. General obesity and central obesity were evaluated based on body mass index (BMI) and waist circumference (WC), calculated through anthropometric measurements and body composition assessments. LMI was calculated by dividing the muscle mass in both legs-measured using the dual-energy X-ray absorptiometry-by body weight. Knee osteoarthritis was defined as a Kellgren-Lawrence scale (KL) grade of ≥2 as assessed through radiographic images. RESULTS: Knee osteoarthritis prevalence, indicated by KL grades, was significantly higher in the general obesity and central obesity groups compared to the normal group, and conversely, lower with varying LMI levels. Using mediation analysis with bootstrapping and adjusting for covariates, we found that LMI mediated the relationship between BMI and KL (ß, 0.005; 95% confidence interval [CI], 0.000 to 0.010) and WC and KL grade (ß, 0.002; 95% CI, 0.001 to 0.003), explaining 4.8% and 6.7% of the total effects of BMI and WC on KL grade, respectively. CONCLUSIONS: The study suggested that LMI partially mediates the link between general obesity and/or central obesity and knee osteoarthritis, proposing that a higher proportion of lower limb muscle mass relative to body weight can alleviate the increased risk of knee osteoarthritis caused by obesity.