Associations amongst dynamic knee stiffness during gait, quadriceps stiffness, and the incidence of knee osteoarthritis over 24 months: a cohort study with a mediation analysis.

BACKGROUND: Decreased strength and increased stiffness of the quadriceps have been associated with a higher risk of developing knee osteoarthritis (OA) in elders. Dynamic joint stiffness (DJS) represents collective resistance from active and passive knee structures for dynamic knee motions. Elevated sagittal knee DJS has been associated with worsening of cartilage loss in knee OA patients. Altered quadriceps properties may affect DJS, which could be a mediator for associations between quadriceps properties and knee OA. Hence, this study aimed to examine whether DJS and quadriceps properties would be associated with the development of clinical knee OA over 24 months, and to explore the mediation role of DJS in associations between quadriceps properties and knee OA. METHODS: This was a prospective cohort study with 162 healthy community-dwelling elders. Gait analysis was conducted to compute DJS during the loading response phase. Quadriceps strength and stiffness were evaluated using a Cybex dynamometer and shear-wave ultrasound elastography, respectively. Knee OA was defined based on clinical criteria 24 months later. Logistic regression with generalized estimating equations was used to examine the association between quadriceps properties and DJS and incident knee OA. Mediation analysis was performed to explore the mediation role of DJS in associations between quadriceps properties and the incidence of knee OA. RESULTS: A total of 125 participants (65.6 ± 4.0 years, 58.4% females) completed the 24-month follow-up, with 36 out of 250 knees identified as clinical knee OA. Higher DJS (OR = 1.86, 95%CI: 1.33-2.62), lower quadriceps strength (1.85, 1.05-3.23), and greater quadriceps stiffness (1.56, 1.10-2.21) were significantly associated with a higher risk of clinical knee OA. Mediation analysis showed that the DJS was not a significant mediator for the associations between quadriceps properties and knee OA. CONCLUSIONS: Higher sagittal knee dynamic joint stiffness, lower quadriceps strength, and greater quadriceps stiffness are potential risk factors for developing clinical knee OA in asymptomatic elders. Associations between quadriceps properties and knee OA may not be mediated by dynamic joint stiffness. Interventions for reducing increased passive properties of the quadriceps and knee joint stiffness may be beneficial for maintaining healthy knees in the aging population.

Blood pressure is associated with knee pain severity in middle-aged and elderly individuals with or at risks for osteoarthritis: data from the Osteoarthritis Initiative.

BACKGROUND: Hypertension is a common comorbidity of osteoarthritis (OA). Joint pain is the main clinical manifestation of OA. Knowledge about the relationship between hypertension and OA pain is limited. This study aimed to investigate whether blood pressure parameters are associated with knee pain severity in individuals with or at risks for OA. METHODS: Our sample consisted of 2598 subjects (60.7% female, aged 45-79 years) collected from the Osteoarthritis Initiative. Blood pressure parameters included blood pressure stage, systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP). Radiographic evaluation using Kellgren-Lawrence system and pain severity evaluation using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Numeric Rating Scale (NRS) were performed for right knee. Linear regression was used to examine the relationship between blood pressure parameters and knee pain severity. RESULTS: For the overall sample, blood pressure stage, SBP, and PP were positively correlated with WOMAC and NRS pain scores when adjusting for age, sex, and body mass index (BMI) (p ≤ 0.024) and were inversely correlated with KOOS score (p ≤ 0.004). After further adjusting for all covariates, PP remained a positive correlation with WOMAC score (p = 0.037) while other associations between blood pressure parameters and pain scores did not reach the statistical significance. In female, higher blood pressure stage, SBP, and PP were significantly associated with increased WOMAC and NRS scores and decreased KOOS score after adjustments of age and BMI (p ≤ 0.018). When adjusting for all covariates, the correlations of PP with WOMAC, KOOS and NRS scores remained significant (p = 0.008-0.049). In male sample, SBP was positively correlated with WOMAC score when adjusting for age and BMI (p = 0.050), but other associations between blood pressure parameters and pain scores were not statistically significant. No significant correlation was observed in male when further adjusting for other covariates. CONCLUSIONS: Increased PP is a risk factor for knee pain and mainly affects females, which suggested that controlling PP may be beneficial in preventing or reducing knee pain in females with or at risks for OA.

Association between Dietary total antioxidant capacity and knee osteoarthritis: a case-control study in the Iranian Population.

AIM: Knee osteoarthritis (KOA) is a prevalent chronic condition associated with significant pain, disability, and healthcare costs, particularly among the elderly population. Despite the considerable burden of KOA, effective treatment options for managing the condition's underlying causes remain limited. This case-control study aims to investigate the relationship between dietary total antioxidant capacity (DTAC) and knee osteoarthritis. METHODS: This case-control study was conducted on 105 patients with confirmed KOA and 210 controls. KOA was diagnosed based on the American College of Rheumatology criteria. Dietary total antioxidant capacity (DTAC) was calculated based on the ferric-reducing antioxidant power method. RESULTS: The mean age and BMI of the participants were 53.6 ± 8.8 years old and 27.3 ± 2.7 kg/m2, respectively. The study participant's DTAC score ranged from 3.56 to 25.32 with a mean and SD of 12.46 ± 5.12. In the crude model, individuals in the highest quartile of DTAC score had 71% lower odds of having knee osteoarthritis compared to those in the first quartile (OR: 0.29, 95%CI: 0.15 to 0.58, P-trend < 0.001). These associations remained significant after adjustment for potential confounders including age, sex, energy intake, family history of osteoarthritis, vitamin D and calcium use, physical activity level, cigarette smoking and BMI. Although the odds of having knee osteoarthritis decreased with increasing quartiles of DTAC in both sexes, this relationship was stronger among males than females. CONCLUSION: The results of this study showed that there was an inverse correlation between DTAC and KOA among the Iranian patients with KOA.

Annual Trends of High Tibial Osteotomy: Analysis of an Official Registry in Italy.

Background and Objectives: Knee osteoarthritis is a serious burden for modern countries. Timing of surgery and treatment choice are still a matter of controversy in the orthopedic literature. The purpose of this study was to ascertain the incidence and hospitalization trends of high tibial osteotomy in Italy from 2001 to 2016. Materials and Methods: Data are sourced from the National Hospital Discharge Reports (SDO) of the Italian Ministry of Health between 2001 and 2016. Results: A total of 34,402 high tibial osteotomies were performed over the study period in Italy. The cumulative incidence was 3.6 cases per 100,000 residents. The age classes 50-54, 55-59 showed the higher number of procedures. In pediatric patients (0-19 years), high tibial osteotomies are also largely performed. The majority of patients having surgery were men with a M/F ratio of 1.5. The mean age of patients was 44.2 ± 19.2 years. Males were significantly younger than females (43.3 ± 20.7 vs. 45.6 ± 17.7). The average length of hospitalization was 6.1 ± 7.3 days. Over the course of the analysis, a declining trend in hospital stay length was seen. The main primary diagnosis codes were "Varus knee" (736.42 ICD-9-CM code, 33.9%), "Osteoarthrosis, localized, primary, leg region" (715.16 ICD-9-CM code, 9.5%). Conclusions: Over the study period, high tibial osteotomies in Italy almost halved. Varus deformity and knee osteoarthritis are the leading causes requiring high tibial osteotomy. Except for the pediatric setting, results showed that from the 20-24 age class to the 50-54 age class, there was an increasing request for knee osteotomy, whereas in those aged >60 years, the incidence progressively decreased. The evident decline in HTO performed over the years in Italy seems to reflect a minor role for knee osteotomy in the management of knee OA, as it seems to be primarily reserved for younger male patients.

Reproductive history is associated with functional disabilities and symptoms in women with knee osteoarthritis: a case-control study.

OBJECTIVES: Studies that have examined the correlation between reproductive history and knee osteoarthritis (KOA) have had heterogeneous findings. We aimed to investigate the reproductive history and its relationship with pain and physical dysfunction in women with KOA. This case-control study, comprising 204 women aged 50 and older with and without KOA recruited through random cluster sampling, was executed from February 2018 to October 2018 in the health centers of Tabriz City. The reproductive history questionnaire was completed for the subjects in two groups. Pain intensity and functional dysfunction caused by KOA were evaluated using the Visual analogue scale and the Western Ontario and McMaster index, respectively. RESULTS: The women's age of menarche in the case group was significantly lower (p = 0.031), and the number of pregnancies (p = 0.017) and the average duration of breastfeeding (p = 0.039) were substantially higher than those of the control group. Older age at the first menstruation (OR = 0.851) was a protective factor, and higher parity (OR = 8.726) was a risk factor for KOA. In the women with KOA, the younger age of the mother at the birth of the first alive baby and the longer duration of breastfeeding were associated with higher pain intensity and functional disorders.

Association of physical activity trajectories over 8 years and risk of knee replacement: data from the osteoarthritis initiative.

BACKGROUND: To identify physical activity (PA) trajectories in adults with or at risk of knee osteoarthritis and to evaluate the association of PA trajectories with incident knee replacement (KR). METHODS: This study used data from the Osteoarthritis Initiative. The Physical Activity Scale for the Elderly and the KR were assessed annually from baseline to 9 years. Individuals were included if they did not undergo KR surgery at baseline and had data on PA at ≥ 1 visit before KR. Latent class growth mixture Modeling was used to identify the optimal trajectories of PA before KR. Log-binomial regression models were used to assess the association between PA trajectories and the risk of KR. Data analyses were conducted in all individuals and those with radiographic osteoarthritis (ROA) and significant knee pain (Western Ontario and McMaster Osteoarthritis Index pain score of ≥ 5 on a 0-20 scale) at baseline, respectively. RESULTS: Of 4731 participants (mean age 61.1 years, 58.5% female), four distinct and slightly declined PA trajectories were identified. Compared to individuals with a "Low" PA trajectory, those with "Medium-low", "Medium-high", or "High" PA trajectories were not significantly associated with the risk of KR (risk ratios: 0.97-1.19, all p > 0.05). Similar PA trajectories and associations with the risk of KR were observed in the subgroups of individuals with radiographic osteoarthritis and those with significant knee pain at baseline, respectively. CONCLUSION: In participants with or at risk of knee osteoarthritis, PA slightly declines over time and may play no role in the risk of KR.

Depression and risk of arthritis: A Mendelian randomization study.

INTRODUCTION: Observational studies have found that most patients with arthritis have depression. We aimed to determine the causal relationship between various types of arthritis and depression. METHODS: We conducted a two-sample bidirectional Mendelian randomized (MR) analysis to determine whether there was a significant causal relationship between depression and multiple types of arthritis. The data of our study were derived from the publicly released genome-wide association studies (GWASs) and the largest GWAS meta-analysis. MR analysis mainly used inverse-variance weighted method; supplementary methods included weighted median, weighted mode, and MR-Egger using MR pleiotropy residual sum and outlier to detect and correct for the presence of pleiotropy. RESULTS: After adjusting for heterogeneity and horizontal pleiotropy, we found that depression was associated with an increased risk of osteoarthritis (OA) (OR = 1.02, 95%CI: 1.01-1.02, p = 2.96 × E - 5). In the reverse analysis, OA was also found to increase the risk of depression (OR = 1.10, 95%CI: 1.04-1.15, p = .0002). Depression only increased the risk of knee OA (KOA) (OR = 1.25, 95%CI: 1.10-1.42, p = 6.46 × E - 4). Depression could potentially increase the risk of spondyloarthritis (OR = 1.52, 95%CI: 1.19-1.94, p ≤ 8.94 × E - 4). CONCLUSION: There is a bidirectional causal relationship of depression with OA. However, depression only augments the risk of developing KOA. Depression may increase the risk of spondyloarthritis and gout.

Risk of carpal tunnel syndrome among patients with osteoarthritis: a US population-based study.

BACKGROUND: Carpal tunnel syndrome (CTS), an entrapment neuropathy caused by pressure of the median nerve, is a progressive condition that can lead to a decreased quality of life. Studies suggest an association between CTS and arthritis; however, previous studies examining osteoarthritis (OA) and CTS are limited in number, scope and study design. This study estimated the incidence and risk of CTS among patients with OA, both overall and by specific joints, in a large population-based cohort in the United States. METHODS: Patients from the Optum claims database aged ≥ 45 years and diagnosed with OA between January 1, 2018, and December 31, 2022, were eligible for the OA cohort. The non-OA cohort included those without a diagnosis of OA at the index date and no history of OA for 12 months pre-index. Baseline characteristics were balanced using propensity score matching. The risk of CTS in the OA and non-OA cohort were evaluated using incidence rates and adjusted hazard ratios that were estimated using Cox regression. RESULTS: After applying the inclusion/exclusion criteria, 3,610,240 of the 6,023,384 adults with a diagnosis of OA remained in the OA cohort. After propensity-score matching, each cohort included 1,033,439 individuals. The incidence rates for CTS per 1000 person-years were 7.35 (95% confidence interval [CI] 7.21-7.49) in the OA cohort and 1.44 (95% CI 1.38-1.50) in the non-OA cohort. The risk of developing CTS in patients with OA was ~ 4 times that of patients without (hazard ratio = 3.80; 95% CI 3.54-4.07). This increased risk was found across all OA joint types, with OA of the hand/wrist having the highest risk for CTS. Additionally, multiple OA joints presented a higher risk compared with a single affected joint. CONCLUSIONS: OA increases the risk of CTS, but this is not limited to patients with hand/wrist OA, suggesting a systemic impact of OA on CTS. While the risk appears highest for patients with hand/wrist OA, patients with more distant affected joints like knee or hip also have an increased risk of CTS.

New-onset Fibromyalgia After Total Knee Replacement in Patients With Osteoarthritis: A Propensity-score-matched Cohort Study in the United States.

BACKGROUND/AIM: The risk of new-onset fibromyalgia after total knee replacement (TKR) in osteoarthritis patients is not well-established. This study aimed to assess the risk of developing fibromyalgia post-TKR, considering potential variations across age and sex. PATIENTS AND METHODS: Utilizing a multicenter retrospective cohort design and data from the TriNetX research network, electronic health records of osteoarthritis patients who underwent TKR and the same number of matched controls were analyzed. Propensity-score matching was performed by matching critical confounders. Hazard ratios were evaluated to assess fibromyalgia risk in the TKR cohort compared to non-TKR controls. RESULTS: The hazard ratio of future fibromyalgia for the TKR cohort was 2.08 (95% confidence interval=1.74-2.49) for 1 year after the index date, 1.81 (95% confidence interval=1.62-2.02) for 3 years, and 1.69 (95% confidence interval=1.54-1.86) for 5 years compared with non-TKR controls. The significant association remained in sensitivity models and stratification analyses in different age and sex subgroups. CONCLUSION: Clinicians should be vigilant about the potential for fibromyalgia development post-TKR and consider tailored interventions; our findings emphasize the need for further research to elucidate underlying mechanisms and identify modifiable risk factors.

[Relationship between hypercholesterolemia and osteoarthritis (preliminary results)].

AIM: To evaluate the relationship of hypercholesterolemia (HCE) with clinical, instrumental, and laboratory parameters in osteoarthritis (OA) in a multicenter, cross-sectional study. MATERIALS AND METHODS: The study included 183 patients aged 40-75 years, with a confirmed diagnosis of stage I-III OA (ACR) of the knee joints, who signed an informed consent. The mean age was 55.6±10.7 years (40 to 75), body mass index was 29.3±6.3 kg/m2, and disease duration was 5 [1; 10] years. For each patient, a case record form was filled out, including anthropometric indicators, medical history, clinical examination data, an assessment of knee joint pain according to VAS, WOMAC, KOOS and comorbidities. All patients underwent standard radiography and ultrasound examination of the knee joints and laboratory tests. RESULTS: HCE was detected in 59% of patients. Depending on its presence or absence, patients were divided into two groups. Patients were comparable in body mass index, waist and hip measurement, and disease duration but differed significantly in age. Individuals with elevated total cholesterol levels had higher VAS pain scores, total WOMAC and its components, an overall assessment of the patient's health, a worse KOOS index, and ultrasound findings (reduced cartilage tissue). HCE patients showed high levels of cholesterol, low-density lipoproteins, triglycerides, STX-II, and COMP (p<0.05). However, after stratification by age, many initial intergroup differences became insignificant, and differences in the WOMAC pain score persisted. CONCLUSION: The results of the study confirmed the high prevalence of HCE in OA patients (59%). Patients with OA and increased total cholesterol have more intense pain in the knee joints.

Physical activity and the osteoarthritis of the knee: A Mendelian randomization study.

Previous studies have reported an association between physical activity and the occurrence and progression of knee osteoarthritis (KOA). However, the existing evidence remains limited and of low-quality. This study aimed to examine the causal relationship between different levels of physical activity and KOA. Instrumental variables, represented by single nucleotide polymorphisms (SNPs), were utilized to capture sedentary behavior, appropriate physical exercise, and excessive physical activity. Aggregated statistics from the UK Biobank genome-wide association study dataset were used to assess the impact of these SNPs on KOA. Causality was estimated using inverse variance weighting (IVW), MR Egger, simple model, weighted median, and weighted model approaches. The stability of the results was assessed through heterogeneity and sensitivity analyses. Mendelian randomization (MR) analysis revealed a strong association between sedentary behavior and KOA, with an odds ratio (OR) of 2.096 (95% CI: 1.506-2.917) and a P value of 1.14 × 10-5. Appropriate physical exercise behavior exhibited a strong negative association with KOA, with an OR of 0.147 (95% CI: 0.037-0.582) and a P value of 0.006. Conversely, excessive physical activity behavior showed a significant positive association with KOA, with an OR of 2.162 (95% CI: 1.327-3.521) and a P value of .002. Our findings indicate that sedentary behavior and excessive physical activity are identified as risk factors for KOA, whereas engaging in appropriate physical exercise emerges as a protective factor against the development of KOA.

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.

Incidence of knee and hip joint replacement associated with cumulative exposure to physical factors at work.

BACKGROUND: Knee osteoarthritis (OA) has been quite consistently associated with high physical workload and specific physical factors at work, while for hip OA, fewer studies are available, which still indicate possible associations with heavy lifting and physical workload. The objective of the study was to assess the association between exposure to workplace physical factors and incidence of knee and hip arthroplasty, as markers of severe OA in these joints. METHODS: The study population was composed of employees 25-60 years who participated in the Turin 2011 census. For each job held since 1995, exposure to physical factors was assigned to individuals in the cohort through a Job-Exposure Matrix constructed from the Italian O*NET database. Using Poisson regression models, the incidence of knee and hip arthroplasty for OA, identified through hospitalizations from 2012 to 2018, was examined in relation to cumulative exposure to 7 different physical hazards and a composite indicator of physical workload constructed from 17 physical factors (Ergo-Index). RESULTS: The risk of knee OA was significantly increased in the highest cumulative exposure quartile of physical workload (incidence rate ratio = 1.98, 95% confidence interval: 1.24-3.16) and of all single hazards examined, compared to the lowest quartile, with significant trends in risk with increasing exposure. In contrast, no association was found with hip OA, whose relative risks were close to or below one in all higher-exposure quartiles of physical workload and of each single hazard. CONCLUSIONS: Our results indicate that exposure to physical hazards at work increases the likelihood of developing knee OA, but not hip OA.

The burden of knee osteoarthritis worldwide, regionally, and nationally from 1990 to 2019, along with an analysis of cross-national inequalities.

OBJECTIVE: To describe the disease burden of knee osteoarthritis (KOA) globally, regionally, and in 204 countries by age, sex, and sociodemographic index (SDI) from 1990 to 2019, and to explore cross-national inequalities across SDI. METHODS: The Global Burden of Disease (GBD) 2019 database collected data on KOA worldwide from 1990 to 2019, including prevalence, incidence, years lived with disability (YLDs). The average annual percentage change (AAPC) was used to measure temporal trends. In addition, the inequality slope index and the health concentration index were calculated to quantify the unequal distribution of the burden of KOA across 204 countries worldwide. RESULTS: In 2019, the global age-standardized prevalence rate increased by 7.5% compared with 1990, and the age-standardized incidence rate increased by about 6.2%; The age-standardized YLDs rate increased by about 7.8%. In addition to the Republic of Korea and the United States of America, the disease burden of KOA has increased year by year in other countries around the world. The incidence of KOA was highest at ages 50-59, while the prevalence and rates of YLDs were highest at ages 75-84. The burden of KOA was higher in women than in men. Cross-country inequality suggests that the inequality in the burden of KOA between high SDI and low SDI countries becomes greater, and that countries with high SDI bear a disproportionately high burden. CONCLUSION: The global KOA burden has risen steadily between 1990 and 2019, and cross-national inequality gaps remain large. Targeted measures must therefore be taken to address this inequality and the increasing global KOA disease burden.

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.

Causal relationship between sarcopenia with osteoarthritis and the mediating role of obesity: a univariate, multivariate, two-step Mendelian randomization study.

BACKGROUND: Recent genetic evidence supports a causal role for sarcopenia in osteoarthritis, which may be mediated by the occurrence of obesity or changes in circulating inflammatory protein levels. Here, we leveraged publicly available genome-wide association study data to investigate the intrinsic causal relationship between sarcopenia, obesity, circulating inflammatory protein levels, and osteoarthritis. METHODS: In this study, we used Mendelian randomization analyses to explore the causal relationship between sarcopenia phenotypes (Appendicular lean mass [ALM], Low hand-grip strength [LHG], and usual walking pace [UWP]) and osteoarthritis (Knee osteoarthritis [KOA], and Hip osteoarthritis [HOA]). Univariable Mendelian randomization (UVMR) analyses were performed using the inverse variance weighted (IVW) method, MR-Egger, weighted median method, simple mode, and weighted mode, with the IVW method being the primary analytical technique. Subsequently, the independent causal effects of sarcopenia phenotype on osteoarthritis were investigated using multivariate Mendelian randomization (MVMR) analysis. To further explore the mechanisms involved, obesity and circulating inflammatory proteins were introduced as the mediator variables, and a two-step Mendelian randomization analysis was used to explore the mediating effects of obesity and circulating inflammatory proteins between ALM and KOA as well as the mediating proportions. RESULTS: UVMR analysis showed a causal relationship between ALM, LHG, UWP and KOA [(OR = 1.151, 95% CI: 1.087-1.218, P = 1.19 × 10-6, PFDR = 7.14 × 10-6) (OR = 1.215, 95% CI: 1.004-1.470; P = 0.046, PFDR = 0.055) (OR = 0.503, 95% CI: 0.292-0.867; P = 0.013, PFDR = 0.027)], and a causal relationship between ALM, UWP and HOA [(OR = 1.181, 95% CI: 1.103-1.265, P = 2.05 × 10-6, PFDR = 6.15 × 10-6) (OR = 0.438, 95% CI: 0.226-0.849, P = 0.014, PFDR = 0.022)]. In the MVMR analyses adjusting for confounders (body mass index, insomnia, sedentary behavior, and bone density), causal relationships were observed between ALM, LHG, UWP and KOA [(ALM: OR = 1.323, 95%CI: 1.224- 1.431, P = 2.07 × 10-12), (LHG: OR = 1.161, 95%CI: 1.044- 1.292, P = 0.006), (UWP: OR = 0.511, 95%CI: 0.290- 0.899, P = 0.020)], and between ALM and HOA (ALM: OR = 1.245, 95%CI: 1.149- 1.348, P = 7.65 × 10-8). In a two-step MR analysis, obesity was identified to play a potential mediating role in ALM and KOA (proportion mediated: 5.9%). CONCLUSIONS: The results of this study suggest that decreased appendicular lean mass, grip strength, and walking speed increase the risk of KOA and decreased appendicular lean mass increases the risk of HOA in patients with sarcopenia in a European population. Obesity plays a mediator role in the occurrence of KOA due to appendicular lean body mass reduction.

Bilateral simultaneous hip and knee replacement: an epidemiological nationwide study from 2001 to 2016.

BACKGROUND: Several studies have compared the pros and cons of simultaneous bilateral versus staged bilateral hip and knee replacement but the outcomes of these two surgical options remains a matter of controversy. This study aimed to evaluate demographic features, incidence and hospitalization rates of bilateral one stage total hip and knee arthroplasty in Italy. METHODS: The Italian Ministry of Health's National Hospital Discharge Reports (SDO) were used to gather data. This study referred to the adult population (+ 20 years of age) from 2001 to 2015 for hip arthroplasty and from 2001 to 2016 for knee arthroplasty. RESULTS: Overall, 1,544 bilateral simultaneous hip replacement were carried out. The incidence rate was 0.21 cases per 100,000 adult Italian residents. Male/female ratio was 1.1. The average days of hospital stay was 11.7 ± 11.8 days. The main primary codified diagnosis was: osteoarthrosis, localized, primary, pelvic region and thigh (ICD code: 715.15). 2,851 bilateral simultaneous knee replacement were carried out. The incidence rate was 0.37 cases per 100,000 adult Italian residents. Male/female ratio was 0.6. The average days of hospital stay was 7.7 ± 5.8 days. The main primary codified diagnosis was: osteoarthrosis, localized, primary, lower leg (ICD code: 715.16). CONCLUSIONS: The burden of hip and knee osteoarthrosis as a leading cause of bilateral joint replacement is significant in Italy. The national registers' longitudinal analysis may provide data for establishing international guidelines regarding the appropriate indications for one stage bilateral simultaneous hip or knee replacement versus two stage.

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.