Effects of dietary weight loss with and without exercise on interstitial matrix turnover and tissue inflammation biomarkers in adults with knee osteoarthritis: the Intensive Diet and Exercise for Arthritis trial (IDEA)

Exercise for osteoarthritis of the knee

BACKGROUND

Knee osteoarthritis (OA) is a major public health issue causing chronic pain, impaired physical function, and reduced quality of life. As there is no cure, self-management of symptoms via exercise is recommended by all current international clinical guidelines. This review updates one published in 2015.

OBJECTIVES

We aimed to assess the effects of land-based exercise for people with knee osteoarthritis (OA) by comparing: 1) exercise versus attention control or placebo; 2) exercise versus no treatment, usual care, or limited education; 3) exercise added to another co-intervention versus the co-intervention alone.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and two trial registries (ClinicalTrials.gov and World Health Organisation International Clinical Trials Registry Platform), together with reference lists, from the date of the last search (1st May 2013) until 4 January 2024, unrestricted by language.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that evaluated exercise for knee OA versus a comparator listed above. Our outcomes of interest were pain severity, physical function, quality of life, participant-reported treatment success, adverse events, and study withdrawals.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane for systematic reviews of interventions.

MAIN RESULTS

We included 139 trials (12,468 participants): 30 (3065 participants) compared exercise to attention control or placebo; 60 (4834 participants) compared exercise with usual care, no intervention or limited education; and 49 (4569 participants) evaluated exercise added to another intervention (e.g. weight loss diet, physical therapy, detailed education) versus that intervention alone. Interventions varied substantially in duration, ranging from 2 to 104 weeks. Most of the trials were at unclear or high risk of bias, in particular, performance bias (94% of trials), detection bias (94%), selective reporting bias (68%), selection bias (57%), and attrition bias (48%). Exercise versus attention control/placebo Compared with attention control/placebo, low-certainty evidence indicates exercise may result in a slight improvement in pain immediately post-intervention (mean 8.70 points better (on a scale of 0 to 100), 95% confidence interval (CI) 5.70 to 11.70; 28 studies, 2873 participants). Moderate-certainty evidence indicates exercise likely results in an improvement in physical function (mean 11.27 points better (on a scale of 0 to 100), 95% CI 7.64 to 15.09; 24 studies, 2536 participants), but little to no improvement in quality of life (mean 6.06 points better (on a scale of 0 to 100), 95% CI -0.13 to 12.26; 6 studies, 454 participants). There was moderate-certainty evidence that exercise likely increases participant-reported treatment success (risk ratio (RR) 1.46, 95% CI 1.11 to 1.92; 2 studies 364 participants), and likely does not increase study withdrawals (RR 1.08, 95% CI 0.92 to 1.26; 29 studies, 2907 participants). There was low-certainty evidence that exercise may not increase adverse events (RR 2.02, 95% CI 0.62 to 6.58; 11 studies, 1684 participants). Exercise versus no treatment/usual care/limited education Compared with no treatment/usual care/limited education, low-certainty evidence indicates exercise may result in an improvement in pain immediately post-intervention (mean 13.14 points better (on a scale of 0 to 100), 95% CI 10.36 to 15.91; 56 studies, 4184 participants). Moderate-certainty evidence indicates exercise likely results in an improvement in physical function (mean 12.53 points better (on a scale of 0 to 100), 95% CI 9.74 to 15.31; 54 studies, 4352 participants) and a slight improvement in quality of life (mean 5.37 points better (on a scale of to 100), 95% CI 3.19 to 7.54; 28 studies, 2328 participants). There was low-certainty evidence that exercise may result in no difference in participant-reported treatment success (RR 1.33, 95% CI 0.71 to 2.49; 3 studies, 405 participants). There was moderate-certainty evidence that exercise likely results in no difference in study withdrawals (RR 1.03, 95% CI 0.88 to 1.20; 53 studies, 4408 participants). There was low-certainty evidence that exercise may increase adverse events (RR 3.17, 95% CI 1.17 to 8.57; 18 studies, 1557 participants). Exercise added to another co-intervention versus the co-intervention alone Moderate-certainty evidence indicates that exercise when added to a co-intervention likely results in improvements in pain immediately post-intervention compared to the co-intervention alone (mean 10.43 points better (on a scale of 0 to 100), 95% CI 8.06 to 12.79; 47 studies, 4441 participants). It also likely results in a slight improvement in physical function (mean 9.66 points better, 95% CI 7.48 to 11.97 (on a 0 to 100 scale); 44 studies, 4381 participants) and quality of life (mean 4.22 points better (on a 0 to 100 scale), 95% CI 1.36 to 7.07; 12 studies, 1660 participants) immediately post-intervention. There was moderate-certainty evidence that exercise likely increases participant-reported treatment success (RR 1.63, 95% CI 1.18 to 2.24; 6 studies, 1139 participants), slightly reduces study withdrawals (RR 0.82, 95% CI 0.70 to 0.97; 41 studies, 3502 participants), and slightly increases adverse events (RR 1.72, 95% CI 1.07 to 2.76; 19 studies, 2187 participants). Subgroup analysis and meta-regression We did not find any differences in effects between different types of exercise, and we found no relationship between changes in pain or physical function and the total number of exercise sessions prescribed or the ratio (between exercise group and comparator) of real-time consultations with a healthcare provider. Clinical significance of the findings To determine whether the results found would make a clinically meaningful difference to someone with knee OA, we compared our results to established 'minimal important difference' (MID) scores for pain (12 points on a 0 to 100 scale), physical function (13 points), and quality of life (15 points). We found that the confidence intervals of mean differences either did not reach these thresholds or included both a clinically important and clinically unimportant improvement.

AUTHORS' CONCLUSIONS

We found low- to moderate-certainty evidence that exercise probably results in an improvement in pain, physical function, and quality of life in the short-term. However, based on the thresholds for minimal important differences that we used, these benefits were of uncertain clinical importance. Participants in most trials were not blinded and were therefore aware of their treatment, and this may have contributed to reported improvements.

Association between type III collagen degradation and local tissue damage of a single joint

Objective

The development of disease-modifying drugs is limited by OA's heterogeneity and the challenge of defining clinical endpoints. Serological biomarkers are considered potential surrogate endpoints, but their contribution from single joints to systemic levels in OA patients is unclear. In this exploratory study we longitudinally assessed systemic biomarker levels' response to tissue damage and healing before and after surgery in patients undergoing knee or hip joint replacement revision for aseptic failure. Patients with chronic pain associated with a prior hip or knee arthroplasty, but not receiving revision surgery were included as control.

Method

The serological biomarker of MMP mediated type III collagen degradation C3M, associated with synovial tissue degradation, was measured at baseline before revision surgery, after revision surgery and at a 6-month follow-up in 48 patients with aseptic loosening of a knee or hip prosthesis and in 18 patients with chronic pain from a hip or knee prosthesis. Longitudinal changes in biomarkers were modeled using linear mixed models.

Results

No differences between the aseptic loosening and chronic pain groups were observed at baseline. Revision surgery in the aseptic loosening group led to a swift increase in C3M, which normalized within 2-3 months. No changes in biomarker level were observed in chronic pain patients over three months.

Conclusion

These findings suggest that tissue damage in a single joint significantly impacts systemic biomarker levels and underscores the relevance of systemic biomarkers in assessing local tissue remodeling.

Effect of lower-limb isokinetic muscle strengthening on knee function and joint contact force in knee osteoarthritis patients awaiting total knee arthroplasty: study protocol for a randomized controlled trial

BACKGROUND

Knee osteoarthritis (OA) is a common and serious joint disease and patients mainly suffer from knee pain and dysfunction, significantly impacting their quality of life and daily activities. Non-pharmacological treatments and total knee arthroplasty (TKA) are the two major treatments for knee OA. TKA is the primary treatment for severe knee OA patients, however, the postoperative rehabilitation results are not entirely satisfactory. To enhance postoperative rehabilitation outcomes, preoperative lower-limb muscle strengthening has aroused attention and demonstrated significant results on functional recovery after TKA. Specifically, isokinetic muscle strengthening (IMS) has been highly anticipated as an efficient training method. Nevertheless, its effects in perioperative and long-term periods of TKA require further investigation. This study aims to evaluate the impact of preoperative lower-limb IMS during the 4 weeks before TKA on the perioperative and postoperative outcomes, with particular attention on knee function, pain, and inflammatory response.

METHODS

In this study, 104 patients awaiting TKA will be randomized to 2 groups: the IMS and health education groups. All patients will be evaluated at baseline, post-intervention, discharge day, and postoperative day 14, with follow-up assessments at 6 weeks, 3, 6, and 12 months after discharge. The primary outcome will be the Knee Injury and Osteoarthritis Outcome Score 3 months after TKA and the medial-to-lateral knee contact force ratio. The secondary outcomes will be changes in lower-limb muscle strength, knee pain, inflammation response, active range of motion, performance-based function (5-times Sit-to-Stand Test, Time Up-and-Go Test, 3 m walking speed), Berg Balance Scale, and surgical need.

DISCUSSION

Lower-limb IMS can improve muscle strength, pain, and function for early knee OA patients. However, the effects of different doses of IMS on perioperative and postoperative knee pain, inflammation response, and function after TKA are inconclusive. This study will provide high-quality evidence to assess the efficacy of IMS in end-stage patients who will undergo TKA. Understanding IMS in end-stage knee OA patients will help guide future surgical management for this population. Trial Registration Chinese Clinical Trial Registry ChiCTR2400088136.

Association of biochemical markers with bone marrow lesion changes on imaging-data from the Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium

BACKGROUND

To assess the prognostic value of short-term change in biochemical markers as it relates to bone marrow lesions (BMLs) on MRI in knee osteoarthritis (OA) over 24 months and, furthermore, to assess the relationship between biochemical markers involved with tissue turnover and inflammation and BMLs on MRI.

METHODS

Data from the Foundation for the National Institutes of Health OA Biomarkers Consortium within the Osteoarthritis Initiative (n = 600) was analyzed. BMLs were measured according to the MRI Osteoarthritis Knee Score (MOAKS) system (0-3), in 15 knee subregions. Serum and urinary biochemical markers assessed were as follows: serum C-terminal crosslinked telopeptide of type I collagen (CTX-I), serum crosslinked N-telopeptide of type I collagen (NTX-I), urinary CTX-Iα and CTX-Iβ, urinary NTX-I, urinary C-terminal cross-linked telopeptide of type II collagen (CTX-II), serum matrix metalloproteinase (MMP)-degraded type I, II, and III collagen (C1M, C2M, C3M), serum high sensitivity propeptide of type IIb collagen (hsPRO-C2), and matrix metalloproteinase-generated neoepitope of C-reactive protein (CRPM). The association between change in biochemical markers over 12 months and BMLs over 24 months was examined using regression models adjusted for covariates. The relationship between C1M, C2M, C3M, hsPRO-C2, and CRPM and BMLs at baseline and over 24 months was examined.

RESULTS

Increases in serum CTX-I and urinary CTX-Iβ over 12 months were associated with increased odds of changes in the number of subregions affected by any BML at 24 months. Increase in hsPRO-C2 was associated with decreased odds of worsening in the number of subregions affected by any BML over 24 months. C1M and C3M were associated with BMLs affected at baseline.

CONCLUSIONS

Short-term changes in serum CTX-I, hsPRO-C2, and urinary CTX-Iβ hold the potential to be prognostic of BML progression on MRI. The association of C1M and C3M with baseline BMLs on MRI warrants further investigation.

The addition of structured lifestyle modifications to a traditional exercise program for the management of patients with knee osteoarthritis: A systematic review and meta-analysis of randomised trials

BACKGROUND

Guidelines recommend exercise for the management of knee osteoarthritis (OA), however, recently it has been suggested that including additional lifestyle modifications with a traditional exercise program may elicit greater benefits than exercise alone.

OBJECTIVES

To investigate the influence of the addition of lifestyle modifications to a traditional exercise program, with respect to functional outcomes and quality of life among individuals with knee OA.

DESIGN

Systematic review and meta-analysis.

METHODS

Four databases were searched to identify randomised controlled trials comparing an exercise program, which included the addition of lifestyle modifications, to an exercise program alone in individuals with knee OA. Methodological quality of included studies was assessed via the PEDro scale. Results synthesis through meta-analysis using a random effects model was conducted to determine the pooled effect on eligible outcomes and a GRADE approach was utilised to rate the certainty of evidence.

RESULTS

Meta-analysis of seven studies showed the inclusion of lifestyle modifications to an exercise program can further decrease pain intensity (SMD -0.68 [95% CI -1.26 to -0.10]), improve joint stiffness (MD -0.69 [95% CI -1.21, -0.17]) and increase physical function (MD -1.26 s ([95% CI -1.34, -1.17]) at six-months. Individual results showed improvements in quality of life with the addition of lifestyle modifications, however, this was not demonstrated through meta-analysis.

CONCLUSION

This systematic review supports the inclusion of additional lifestyle modifications to a traditional exercise program, for pain intensity, joint stiffness and physical function for individuals with knee OA.

TRIAL REGISTRATION

PROSPERO registration number: CRD42021279594.

Relevance of Biomarkers in Serum vs. Synovial Fluid in Patients with Knee Osteoarthritis

The association between structural changes and pain sensation in osteoarthritis (OA) remains unclear. Joint deterioration in OA leads to the release of protein fragments that can either systemically (serum) or locally (synovial fluid; SF) be targeted as biomarkers and describe structural changes and potentially pain. Biomarkers of collagen type I (C1M), type II (C2M), type III (C3M), type X (C10C), and aggrecan (ARGS) degradation were measured in the serum and SF of knee OA patients. Spearman's rank correlation was used to assess the correlation of the biomarkers' levels between serum and SF. Linear regression adjusted for confounders was used to evaluate the associations between the biomarkers' levels and clinical outcomes. The serum C1M levels were negatively associated with subchondral bone density. The serum C2M levels were negatively associated with KL grade and positively associated with minimum joint space width (minJSW). The C10C levels in SF were negatively associated with minJSW and positively associated with KL grade and osteophyte area. Lastly, the serum C2M and C3M levels were negatively associated with pain outcomes. Most of the biomarkers seemed to mainly be associated with structural outcomes. The overall biomarkers of extracellular matrix (ECM) remodeling in serum and SF may provide different information and reflect different pathogenic processes.

Diacerein plus glucosamine hydrochloride improves the safety and efficacy and inhibit inflammatory factors in the treatment of knee osteoarthritis

OBJECTIVES

The aim of this study is to elucidate the safety and efficacy of diacerein (DIA) plus glucosamine hydrochloride (GlcN·HCl) in the treatment of knee osteoarthritis (KOA) and their effect on inflammatory factors (IFs).

METHODS

Retrospectively, 116 KOA patients admitted between August 2018 and August 2021 were selected. Among them, 55 cases received DIA monotherapy (control group, Con) and 61 cases received DIA + GlcN·HCl (observation group, Obs). The efficacy, safety, scores of Lequesne Index, and Visual Analogue Scale (VAS), as well as the levels of IFs of the two groups were observed and compared. Further, Cox regression was used to perform an in-depth analysis of factors influencing the occurrence of complications in patients with KOA.

RESULTS

The analyses revealed a higher overall response rate and a lower adverse event rate in the Obs group compared with the Con group, with statistical significance. Decreased scores of Lequesne Index and VAS and levels of IFs were determined in the Obs after treatment, which were all significantly lower compared with those of the Con. Cox regression analysis identified that TNF-α, IL-1β, hs-CRP, and treatment mode affected the occurrence of complications in KOA patients.

CONCLUSIONS

DIA + GlcN·HCl can significantly inhibit the inflammation level in KOA, with definite curative effects and a favorable safety profile.

Dietary inflammation index and osteoarthritis in the elderly: is there a mediating role of physical activity?

We examined whether physical activity (PA) explains the association between dietary inflammatory potential and osteoarthritis (OA) in the elderly. A total of 1249 elderly people (≥65 years) were eligible for this study from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016. The semi-quantitative Food Frequency Questionnaire (FFQ) and Global PA Questionnaire (GPAQ) were used to evaluate the diet and PA of the elderly, respectively. The multivariable logistic regression model estimated the odds ratio (OR) and 95% confidence interval (CI) between Energy-adjusted Dietary Inflammatory Index (E-DII) and OA. The interaction of E-DII and PA on depressive events was tested, and the mediation analysis of PA was performed. The average E-DII in this study was +0.68 (SE 0.08), and the score ranges from -5.32 (most anti-inflammatory) to +4.26 (most pro-inflammatory). In comparison with the first quartile, the elderly from the second quartile (OR: 1.16 [95% CI: 1.06, 1.68]) to the fourth quartile (OR: 1.64 [95% CI: 1.13, 2.37]) had a higher risk of OA before adjustment for PA. An interaction was observed between E-DII and PA in terms of the risk of OA (P_Interaction < 0.001). The whole related part was mediated by PA (20.08%). Our findings indicated that the higher pro-inflammatory potential of diet was associated with a higher risk of OA, and low PA was an important part of the mediating factor in the relationship between systemic low-grade dietary inflammation and the risk of OA.

Adjunctive therapies in addition to land-based exercise therapy for osteoarthritis of the hip or knee

BACKGROUND

Land-based exercise therapy is recommended in clinical guidelines for hip or knee osteoarthritis. Adjunctive non-pharmacological therapies are commonly used alongside exercise in hip or knee osteoarthritis management, but cumulative evidence for adjuncts to land-based exercise therapy is lacking.

OBJECTIVES

To evaluate the benefits and harms of adjunctive therapies used in addition to land-based exercise therapy compared with placebo adjunctive therapy added to land-based exercise therapy, or land-based exercise therapy only for people with hip or knee osteoarthritis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, PsycINFO, EMBASE, CINAHL, Physiotherapy Evidence Database (PEDro) and clinical trials registries up to 10 June 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs of people with hip or knee osteoarthritis comparing adjunctive therapies alongside land-based exercise therapy (experimental group) versus placebo adjunctive therapies alongside land-based exercise therapy, or land-based exercise therapy (control groups). Exercise had to be identical in both groups. Major outcomes were pain, physical function, participant-reported global assessment, quality of life (QOL), radiographic joint structural changes, adverse events and withdrawals due to adverse events. We evaluated short-term (6 months), medium-term (6 to 12 months) and long-term (12 months onwards) effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, and assessed risk of bias and certainty of evidence for major outcomes using GRADE.

MAIN RESULTS

We included 62 trials (60 RCTs and 2 quasi-RCTs) totalling 6508 participants. One trial included people with hip osteoarthritis, one hip or knee osteoarthritis and 59 included people with knee osteoarthritis only. Thirty-six trials evaluated electrophysical agents, seven manual therapies, four acupuncture or dry needling, or taping, three psychological therapies, dietary interventions or whole body vibration, two spa or peloid therapy and one foot insoles. Twenty-one trials included a placebo adjunctive therapy. We presented the effects stratified by different adjunctive therapies along with the overall results. We judged most trials to be at risk of bias, including 55% at risk of selection bias, 74% at risk of performance bias and 79% at risk of detection bias. Adverse events were reported in eight (13%) trials. Comparing adjunctive therapies plus land-based exercise therapy against placebo therapies plus exercise up to six months (short-term), we found low-certainty evidence for reduced pain and function, which did not meet our prespecified threshold for a clinically important difference. Mean pain intensity was 5.4 in the placebo group on a 0 to 10 numerical pain rating scale (NPRS) (lower scores represent less pain), and 0.77 points lower (0.48 points better to 1.16 points better) in the adjunctive therapy and exercise therapy group; relative improvement 10% (6% to 15% better) (22 studies; 1428 participants). Mean physical function on the Western Ontario and McMaster (WOMAC) 0 to 68 physical function (lower scores represent better function) subscale was 32.5 points in the placebo group and reduced by 5.03 points (2.57 points better to 7.61 points better) in the adjunctive therapy and exercise therapy group; relative improvement 12% (6% better to 18% better) (20 studies; 1361 participants). Moderate-certainty evidence indicates that adjunctive therapies did not improve QOL (SF-36 0 to 100 scale, higher scores represent better QOL). Placebo group mean QOL was 81.8 points, and 0.75 points worse (4.80 points worse to 3.39 points better) in the placebo adjunctive therapy group; relative improvement 1% (7% worse to 5% better) (two trials; 82 participants). Low-certainty evidence (two trials; 340 participants) indicates adjunctive therapies plus exercise may not increase adverse events compared to placebo therapies plus exercise (31% versus 13%; risk ratio (RR) 2.41, 95% confidence interval (CI) 0.27 to 21.90). Participant-reported global assessment was not measured in any studies. Compared with land-based exercise therapy, low-certainty evidence indicates that adjunctive electrophysical agents alongside exercise produced short-term (0 to 6 months) pain reduction of 0.41 points (0.17 points better to 0.63 points better); mean pain in the exercise-only group was 3.8 points and 0.41 points better in the adjunctive therapy plus exercise group (0 to 10 NPRS); relative improvement 7% (3% better to 11% better) (45 studies; 3322 participants). Mean physical function (0 to 68 WOMAC subscale) was 18.2 points in the exercise group and 2.83 points better (1.62 points better to 4.04 points better) in the adjunctive therapy plus exercise group; relative improvement 9% (5% better to 13% better) (45 studies; 3323 participants). These results are not clinically important. Mean QOL in the exercise group was 56.1 points and 1.04 points worse in the adjunctive therapies plus exercise therapy group (1.04 points worse to 3.12 points better); relative improvement 2% (2% worse to 5% better) (11 studies; 1483 participants), indicating no benefit (low-certainty evidence). Moderate-certainty evidence indicates that adjunctive therapies plus exercise probably result in a slight increase in participant-reported global assessment (short-term), with success reported by 45% in the exercise therapy group and 17% more individuals receiving adjunctive therapies and exercise (RR 1.37, 95% CI 1.15 to 1.62) (5 studies; 840 participants). One study (156 participants) showed little difference in radiographic joint structural changes (0.25 mm less, 95% CI -0.32 to -0.18 mm); 12% relative improvement (6% better to 18% better). Low-certainty evidence (8 trials; 1542 participants) indicates that adjunctive therapies plus exercise may not increase adverse events compared with exercise only (8.6% versus 6.5%; RR 1.33, 95% CI 0.78 to 2.27).

AUTHORS' CONCLUSIONS

Moderate- to low-certainty evidence showed no difference in pain, physical function or QOL between adjunctive therapies and placebo adjunctive therapies, or in pain, physical function, QOL or joint structural changes, compared to exercise only. Participant-reported global assessment was not reported for placebo comparisons, but there is probably a slight clinical benefit for adjunctive therapies plus exercise compared with exercise, based on a small number of studies. This may be explained by additional constructs captured in global measures compared with specific measures. Although results indicate no increased adverse events for adjunctive therapies used with exercise, these were poorly reported. Most studies evaluated short-term effects, with limited medium- or long-term evaluation. Due to a preponderance of knee osteoarthritis trials, we urge caution in extrapolating the findings to populations with hip osteoarthritis.

Clinical monitoring in osteoarthritis: Biomarkers

OBJECTIVE

The purpose of this overview of osteoarthritis (OA) biomarkers is to provide the non-specialist with a toolbox, based on experience acquired by biomarker researchers over many years, to understand biomarkers in general and their use in the OA field.

METHODS

We provide an update on this subject since the OARSI Primer on osteoarthritis (OA) nearly a decade ago.

RESULTS

Since the last update, the importance of molecular biomarkers has been increasingly recognized in the field, but no OA-related biomarkers have been adopted for routine use in clinical practice. The current lack of chondroprotective treatments for OA impairs the assessment, validation and qualification of the potential role of biomarkers as tools for monitoring disease status and patient responses to treatment of OA. Yet there is no lack of an evolving compendium of OA-related biomarkers, ever more fit-for-purpose, that could currently facilitate drug development for OA. We provide an abbreviated update and overview of specific soluble OA-related biomarkers for this new OARSI Primer on OA with OA-relevant examples encompassing the concepts of biomarker nomenclature, qualification, interpretation, measurement, reporting requirements, application to research, drug discovery and clinical care, and future needs for biomarker advancement.

CONCLUSION

Appropriate biomarkers should play a role at all stages of OA diagnosis, prognosis, drug development, and treatment. The future of OA biomarker research and development holds great promise as its foundation is increasingly robust.

Mind the Gap: Exploring Nutritional Health Compared With Weight Management Interests of Individuals with Osteoarthritis

Background

For persons with osteoarthritis (OA), nutrition education may facilitate weight and OA symptom management.

Objectives

The primary aim of this study was to determine preferred OA-related nutritional and weight management topics and their preferred delivery modality. The secondary aim was to determine whether there is a disconnect between what patients want to know about nutrition and OA management and what information health-care professionals (HCPs) are providing to patients.

Methods

The Osteoarthritis Action Alliance surveyed individuals with OA to identify their preferences, categorized in 4 domains: 1) strategies for weight management and a healthy lifestyle; 2) vitamins, minerals, and other supplements; 3) foods or nutrients that may reduce inflammation; and 4) diets for weight loss. HCPs were provided these domains and asked which topics they discussed with patients with OA. Both groups were asked to select currently utilized or preferred formats of nutritional resources.

Results

Survey responses from 338 individuals with OA and 104 HCPs were included. The highest preference rankings in each domain were: 1) foods that make OA symptoms worse (65%), foods and nutrients to reduce inflammation (57%), and healthy weight loss (42%); 2) glucosamine (53%), vitamin D (49%), and omega-3 fatty acids (45%); 3) spices and herbs (65%), fruits and vegetables (58%), and nuts (40%); and 4) Mediterranean diet (21%), low-carbohydrate diet (18%), and fasting or intermittent fasting (15%). There was greater than 20% discrepancy between interests reported by individuals with OA and discussions reported by HCPs on: weight loss strategies, general information on vitamins and minerals, special dietary considerations for other conditions, mindful eating, controlling caloric intake or portion sizes, and what foods worsen OA symptoms. Most respondents preferred to receive nutrition information in a passive format and did not want information from social media messaging.

Conclusions

There is disparity between the nutrition education content preferred by individuals with OA (which often lacks empirical support) and evidence-based topics being discussed by HCPs. HCPs must communicate evidence-based management of joint health and OA symptoms in patient-preferred formats. This study explored the information gap between what individuals with OA want to know and what HCPs believe they need to know.

Conservative treatment of knee osteoarthritis: A review of the literature

Knee osteoarthritis (KOA) is a common chronic debilitating disease with an estimated prevalence of 23.9% in the general adult population. The condition is characterised by joint pain, functional impairment and significant reduction in quality of life. Management for KOA can generally be divided into conservative (non-operative) and surgical (operative) measures. Conservative management broadly compromises pharmacological and non-pharmacological options and is conventionally the first line treatment to avoid or delay the need for surgical management. The aim of this study is to provide an overview of the current recommendations, efficacy and safety profile of different conservative treatments through a review of the literature.

Osteoarthritis endotype discovery via clustering of biochemical marker data

OBJECTIVES

Osteoarthritis (OA) patient stratification is an important challenge to design tailored treatments and drive drug development. Biochemical markers reflecting joint tissue turnover were measured in the IMI-APPROACH cohort at baseline and analysed using a machine learning approach in order to study OA-dominant phenotypes driven by the endotype-related clusters and discover the driving features and their disease-context meaning.

METHOD

Data quality assessment was performed to design appropriate data preprocessing techniques. The k-means clustering algorithm was used to find dominant subgroups of patients based on the biochemical markers data. Classification models were trained to predict cluster membership, and Explainable AI techniques were used to interpret these to reveal the driving factors behind each cluster and identify phenotypes. Statistical analysis was performed to compare differences between clusters with respect to other markers in the IMI-APPROACH cohort and the longitudinal disease progression.

RESULTS

Three dominant endotypes were found, associated with three phenotypes: C1) low tissue turnover (low repair and articular cartilage/subchondral bone turnover), C2) structural damage (high bone formation/resorption, cartilage degradation) and C3) systemic inflammation (joint tissue degradation, inflammation, cartilage degradation). The method achieved consistent results in the FNIH/OAI cohort. C1 had the highest proportion of non-progressors. C2 was mostly linked to longitudinal structural progression, and C3 was linked to sustained or progressive pain.

CONCLUSIONS

This work supports the existence of differential phenotypes in OA. The biomarker approach could potentially drive stratification for OA clinical trials and contribute to precision medicine strategies for OA progression in the future.

TRIAL REGISTRATION NUMBER

NCT03883568.

Increase in Free and Total Plasma TGF-β1 Following Physical Activity

OBJECTIVE

To evaluate effects of physical activity and food consumption on plasma concentrations of free and total transforming growth factor beta-1 (TGF-β1), beta-2 (TGF-β2), and beta-3 (TGF-β3) in individuals with knee osteoarthritis (OA).

METHODS

Participants (n = 40 in 2 cohorts of 20; mean age 70 years) with radiographic knee OA were admitted overnight for serial blood sampling. Cohorts 1 and 2 assessed the impacts of food intake and activity, respectively, on TGF-β concentrations. Cohort 1 blood draws included 2 hours postprandial the evening of day 1 (T3), fasting before rising on day 2 (T0), nonfasting 1 hour after rising (T1B), and 4 hours after rising (T2). Cohort 2 blood draws included T3, T0, fasting 1 hour after rising and performing activities of daily living (T1A), and nonfasting 2 hours after rising (T1B). By sandwich ELISAs, we quantified plasma free and total TGF-β1 concentrations in all samples, and plasma total TGF-β2 and TGF-β3 in cohort 2.

RESULTS

Free TGF-β1 represented a small fraction of the total systemic concentration (mean 0.026%). In cohort 2, free and total TGF-β1 and total TGF-β2 concentration significantly increased in fasting samples collected after an hour (T1A) of activities of daily living (free TGF-β1: P = 0.006; total TGF-β1: P < 0.001; total TGF-β2: P = 0.001). Total TGF-β3 increased nonsignificantly following activity (P = 0.590) and decreased (P = 0.035) after food consumption while resting (T1B).

CONCLUSIONS

Increased plasma concentrations of TGF-β with physical activity suggests activity should be standardized prior to TGF-β1 analyses.

A matrix metalloproteinase-generated neoepitope of CRP can identify knee and multi-joint inflammation in osteoarthritis

OBJECTIVE

To compare C-reactive protein (CRP) and matrix metalloproteinase-generated neoepitope of CRP (CRPM) as biomarkers of inflammation and radiographic severity in patients with knee osteoarthritis.

METHODS

Participants with symptomatic osteoarthritis (n=25) of at least one knee underwent knee radiographic imaging and radionuclide etarfolatide imaging to quantify inflammation of the knees and other appendicular joints. For purposes of statistical analysis, semi-quantitative etarfolatide and radiographic imaging scores were summed across the knees; etarfolatide scores were also summed across all joints to provide a multi-joint synovitis measure. Multiple inflammation and collagen-related biomarkers were measured by ELISA including CRP, CRPM, MMP-generated neoepitopes of type I collagen and type III collagen in serum (n=25), and CD163 in serum (n=25) and synovial fluid (n=18).

RESULTS

BMI was associated with CRP (p=0.001), but not CRPM (p=0.753). Adjusting for BMI, CRP was associated with radiographic knee osteophyte score (p=0.002), while CRPM was associated with synovitis of the knee (p=0.017), synovitis of multiple joints (p=0.008), and macrophage marker CD163 in serum (p=0.009) and synovial fluid (p=0.03). CRP correlated with MMP-generated neoepitope of type I collagen in serum (p=0.045), and CRPM correlated with MMP-generated neoepitope of type III collagen in serum (p<0.0001). No biomarkers correlated with age, knee pain, or WOMAC pain.

CONCLUSIONS

To our knowledge, this is the first time that CRPM has been shown to be associated with knee and multi-joint inflammation based on objective imaging (etarfolatide) and biomarker (CD163) measures. These results demonstrate the capability of biomarker measurements to reflect complex biological processes and for neoepitope markers to more distinctly reflect acute processes than their precursor proteins. CRPM is a promising biomarker of local and systemic inflammation in knee OA that is associated with cartilage degradation and is independent of BMI. CRPM is a potential molecular biomarker alternative to etarfolatide imaging for quantitative assessment of joint inflammation.

Association between Markers of Synovial Inflammation, Matrix Turnover and Symptoms in Knee Osteoarthritis: A Cross-Sectional Study

To investigate the association between markers of synovial inflammation and matrix turnover (MRI-based and serum biomarkers) and knee symptoms in established knee osteoarthritis (KOA). This cross-sectional study utilised data from a randomised, multicentre placebo-controlled trial (UK-VIDEO) of vitamin D therapy in symptomatic KOA. Data on serum biomarkers, type III collagen degradation (C3M), metabolite of C-reactive protein (CRPM) and cartilage oligomeric matrix protein (COMP), were available at baseline whilst contrast-enhanced (CE) MRI data were acquired in a subsample at baseline and annually. Knee symptoms were assessed using WOMAC at all visits. We examined the cross-sectional association between knee symptoms and three MRI-based and three serum markers of synovitis and matrix turnover, respectively. A total of 447 participants were included in the serum and 136 participants in the MRI analyses. MRI-defined medial perimeniscal synovitis was positively associated with knee pain and, suprapatellar and medial perimeniscal synovitis with knee function in multivariate analysis. We observed a statistically significant, negative association between a higher concentration of serum C3M and CRPM and knee pain, respectively. Furthermore, the highest CRPM quartile was negatively associated with knee function. Our findings suggest that, in established painful radiographic KOA, MRI-defined medial perimeniscal and suprapatellar synovitis were positively associated with knee symptoms. Serum-based C3M and CRPM markers were negatively associated with knee symptoms. Pain fluctuations are common in KOA and a better understanding of the relationship between markers of synovitis and matrix turnover and knee symptoms would facilitate a more accurate assessment of temporal changes in disease progression.

Cynandione A and PHA-543613 inhibit inflammation and stimulate macrophageal IL-10 expression following α7 nAChR activation

Cynandione A, an acetophenone isolated from Cynanchum Wilfordii Radix, attenuates inflammation. The present study aimed to study the mechanisms underlying cynandione A-induced antiinflammation. Treatment with cynandione A and the specific α7 nicotinic acetylcholine receptor (α7 nAChR) agonist PHA-543613 remarkably reduced overexpression of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β in lipopolysaccharide (LPS)-treated RAW264.7 cells and primary peritoneal macrophages, and endotoxemic mice. Both cynandione A and PHA-543613 also stimulated IL-10 expression in naïve and LPS-treated macrophages and endotoxemic mice. Cynandione A- and PHA-543613-inhibited proinflammatory cytokine expression was completely blocked by the α7 nAChR antagonist methyllycaconitine and the IL-10 antibody. The stimulatory effect of cynandione A and PHA-543613 on IL-10 expression were suppressed by methyllycaconitine and knockdown of α7 nAChRs using siRNA/α7 nAChR. Cynandione A significantly stimulated STAT3 phosphorylation, which was attenuated by methyllycaconitine and the IL-10 neutralizing antibody. The STAT3 activation inhibitor NSC74859 also blocked cynandione A-inhibited proinflammatory cytokine expression. Taken together, our results, for the first time, demonstrate that cynandione A and PHA-543613 inhibit inflammation through macrophageal α7 nAChR activation and subsequent IL-10 expression.

From Pathogenesis to Therapy in Knee Osteoarthritis: Bench-to-Bedside

Osteoarthritis (OA) is currently the most widespread musculoskeletal condition and primarily affects weight-bearing joints such as the knees and hips. Importantly, knee OA remains a multifactorial whole-joint disease, the appearance and progression of which involves the alteration of articular cartilage as well as the synovium, subchondral bone, ligaments, and muscles through intricate pathomechanisms. Whereas it was initially depicted as a predominantly aging-related and mechanically driven condition given its clear association with old age, high body mass index (BMI), and joint malalignment, more recent research identified and described a plethora of further factors contributing to knee OA pathogenesis. However, the pathogenic intricacies between the molecular pathways involved in OA prompted the study of certain drugs for more than one therapeutic target (amelioration of cartilage and bone changes, and synovial inflammation). Most clinical studies regarding knee OA focus mainly on improvement in pain and joint function and thus do not provide sufficient evidence on the possible disease-modifying properties of the tested drugs. Currently, there is an unmet need for further research regarding OA pathogenesis as well as the introduction and exhaustive testing of potential disease-modifying pharmacotherapies in order to structure an effective treatment plan for these patients.

Nonsurgical Management of Cartilage Defects of the Knee: Who, When, Why, and How?

The nonoperative practitioner managing individuals with cartilage defects should use a patient-centered, multifaceted approach that aims to individualize treatment to provide optimal benefit. These include addressing modifiable risk factors for disease progression and instituting interventions such as weight loss, nutrition, physical activity, and potentially regenerative medicine strategies. This review will focus on these nonoperative treatment strategies with a focus on when treatments are necessary, who will benefit from these approaches, why they are specifically appropriate, and, finally, how these treatments directly modify the structure of a patient's cartilage and resulting symptoms.

Emerging Technologies and Platforms for the Immunodetection of Multiple Biochemical Markers in Osteoarthritis Research and Therapy

Biomarkers, especially biochemical markers, are important in osteoarthritis (OA) research, clinical trials, and drug development and have potential for more extensive use in therapeutic monitoring. However, they have not yet had any significant impact on disease diagnosis and follow-up in a clinical context. Nevertheless, the development of immunoassays for the detection and measurement of biochemical markers in OA research and therapy is an active area of research and development. The evaluation of biochemical markers representing low-grade inflammation or extracellular matrix turnover may permit OA prognosis and expedite the development of personalized treatment tailored to fit particular disease severities. However, currently detection methods have failed to overcome specific hurdles such as low biochemical marker concentrations, patient-specific variation, and limited utility of single biochemical markers for definitive characterization of disease status. These challenges require new and innovative approaches for development of detection and quantification systems that incorporate clinically relevant biochemical marker panels. Emerging platforms and technologies that are already on the way to implementation in routine diagnostics and monitoring of other diseases could potentially serve as good technological and strategic examples for better assessment of OA. State-of-the-art technologies such as advanced multiplex assays, enhanced immunoassays, and biosensors ensure simultaneous screening of a range of biochemical marker targets, the expansion of detection limits, low costs, and rapid analysis. This paper explores the implementation of such technologies in OA research and therapy. Application of novel immunoassay-based technologies may shed light on poorly understood mechanisms in disease pathogenesis and lead to the development of clinically relevant biochemical marker panels. More sensitive and specific biochemical marker immunodetection will complement imaging biomarkers and ensure evidence-based comparisons of intervention efficacy. We discuss the challenges hindering the development, testing, and implementation of new OA biochemical marker assays utilizing emerging multiplexing technologies and biosensors.

Weight control in older adults with knee osteoarthritis: a qualitative study

Background

Knee osteoarthritis (OA) affects mostly older adults and its primary risk factor is obesity. This study sought to understand weight-control strategies, facilitators of and barriers toward weight control in older adults with knee OA who preferred not to undergo physician-recommended total knee arthroplasty.

Methods

For this qualitative descriptive study, older outpatients (N = 118) were recruited from orthopedic clinics at three hospitals. Data were collected through face-to face, individual in-depth interviews using a semi-structured interview guide and analyzed using content analysis.

Results

Among participants, only 25.4% had body weight in the normal range and 55.9% reported having controlled their weight. Their most common weight-control strategies were to control diet and to exercise and control diet together. Weight control was facilitated by desiring good health, wanting to improve walking or movement, perceiving that they had gained weight, wanting to look good, and advice from healthcare providers. Common barriers to participants’ weight control were perceiving that dietary control was not needed, controlling appetite was difficult, dietary control was difficult, and not eating was physically uncomfortable.

Conclusions

Our findings help healthcare providers understand how older adults with knee OA perceive weight control and serve as a reference for developing weight-control programs. Health care providers can integrate these identified facilitators and barriers into a weight-control intervention program. The importance of weighing oneself every day, the meaning of body mass index, consulting with a dietician regularly to control weight, and providing appropriate knowledge about aging and weight control should also be included in any weight-control intervention program.

Impact of Exercise Therapy on Molecular Biomarkers Related to Cartilage and Inflammation in Individuals at Risk of, or With Established, Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To investigate the impact of exercise therapy on molecular biomarkers related to cartilage and inflammation in individuals at risk of, or with established, knee osteoarthritis by conducting a systematic review of randomized controlled trials (RCTs).

METHODS

We conducted a literature search up to September 2017 in 5 major databases with no restriction on publication year or language. Data were extracted from the first available follow-up time point, and we performed a narrative synthesis for the effect of exercise therapy on molecular biomarkers related to cartilage and inflammation. A subset of studies reporting sufficient data was combined in a meta-analysis, using an adjusted random-effects model.

RESULTS

Twelve RCTs involving 57 study comparisons at 4 to 24 weeks following an exercise-therapy intervention were included. Exercise therapy decreased molecular biomarkers in 17 study comparisons (30%), had no effect in 36 (63%), and increased molecular biomarkers in 4 study comparisons (7%). Meta-analyses of 9 biomarkers showed that exercise therapy was associated with nonsignificant reductions of the C-reactive protein level, C-terminal crosslinking telopeptide of type II collagen, tumor necrosis factor (TNF), soluble TNF receptors 1 and 2, C2C neoepitope of type II collagen, and cartilage oligomeric matrix protein, compared to nonexercising control groups, and exercise therapy had no effect on interleukin-6 and soluble interleukin-6 receptor.

CONCLUSION

Exercise therapy is not harmful, because it does not increase the concentration of molecular biomarkers related to cartilage turnover and inflammation, implicated in osteoarthritis progression. The overall quality of evidence was downgraded to low because of the limited number of RCTs available.

Blood and urinary collagen markers in osteoarthritis: markers of tissue turnover and disease activity

Introduction: The need for diagnostic markers in osteoarthritis (OA) is acute and immediate, as sensitive and precise tools that monitor disease activity and treatment response are lacking. Collagens - types I, II, and III - are the skeleton of the extracellular matrix of joint tissues. Joint collagens are generally turned over at a low rate, but the balance between formation and degradation is disturbed, leading to the loss of, for example, cartilage.Areas covered: We discuss the markers reflecting collagen turnover and provide examples of how they have been applied in OA research, as well as how we believe these should be used in the future. We have searched PubMed for full-text articles written in English using different combinations of the following terms: OA, biomarker, and collagen. The result is a narrative review that gives examples from the literature.Expert opinion: Collagen markers show promise, as they are direct measures of tissue balance. Until now, collagen markers have mainly been tested in observational cohorts, which may provide insights into the association between the candidate marker and clinical variables; however, these do not advance the development of qualified markers that can be used for drug development or in clinical practice.

CITED2 mediates the mechanical loading-induced suppression of adipokines in the infrapatellar fat pad

Adipokines secreted from the infrapatellar fat pad (IPFP), such as adipsin and adiponectin, have been implicated in osteoarthritis pathogenesis. CITED2, a mechanosensitive transcriptional regulator with chondroprotective activity, may modulate their expression. Cited2 haploinsufficient mice (Cited2^+/- ) on a high-fat diet (HFD) exhibited increased body weight and increased IPFP area compared to wild-type (WT) mice on an HFD. While an exercise regimen of moderate treadmill running induced the expression of CITED2, as well as PGC-1α, and reduced the expression of adipsin and adiponectin in the IPFP of WT mice on an HFD, Cited2 haploinsufficiency abolished the loading-induced expression of PGC-1α and loading-induced suppression of adipsin and adiponectin. Furthermore, knocking down or knocking out CITED2 in adipose stem cells (ASCs)/preadipocytes derived from the IPFP in vitro led to the increased expression of adipsin and adiponectin and reduced PGC-1α, and abolished the loading-induced suppression of adipsin and adiponectin and loading-induced expression of PGC-1α. Overexpression of PGC-1α in these ASC/preadipocytes reversed the effects caused by CITED2 deficiency. The current data suggest that CITED2 is a critical regulator in physiologic loading-induced chondroprotection in the context of an HFD and PGC-1α is required for the inhibitory effects of CITED2 on the expression of adipokines such as adipsin and adiponectin in the IPFP.

Osteoarthritis year in review 2018: biomarkers (biochemical markers)

OBJECTIVE

The aim of this narrative review is to summarize important findings from biochemical marker studies relevant to osteoarthritis (OA) in the context of new discoveries and clinical and scientific need.

DESIGN

We conducted a systematic search of electronic medical databases (Embase, Medline, Web of Science, Cochrane central) between 01-03-2017 and 31-03-2018. The search was restricted to human studies, English language and full text available publications while reviews were excluded. Only papers describing protein based biomarkers measured in human body fluids (blood, urine and synovial fluid (SF)) were included. Of the 992 papers, 86 were reviewed here, with inclusion primarily based on relevance to OA biochemical markers.

RESULTS

This review highlights a selection of studies based on their quality and perceived importance to the field mainly including those that¹ evaluate prognostic value of biomarkers for OA progression (i.e., biomarkers reflecting change in composition of joint tissues and biomarkers of inflammation)², help in assessment of intervention efficacy, and³ are innovative and uncover new candidate biomarkers, or use new approaches in biomarker discovery.

CONCLUSIONS

Key findings and implications for possible clinical utility of biochemical markers are summarized and discussed. Given the paucity of robust biomarkers within the field, and the heterogeneity of the condition, enormous works are needed for development and validation of novel and clinically applicable biomarkers to reduce the impact of this highly prevalent and debilitating condition.

Is a model of stratified exercise therapy by physical therapists in primary care feasible in patients with knee osteoarthritis? : a mixed methods study

OBJECTIVES

To explore the feasibility of a newly developed model of stratified exercise therapy in primary care for patients with knee osteoarthritis (OA).

DESIGN

Mixed method design (process, outcome and qualitative evaluation).

SETTING

Six physical therapy practices in primary care around Amsterdam.

PARTICIPANTS

Fifty eligible patients with knee OA, visiting one of the participating physical therapists (PTs).

INTERVENTION

Patients were allocated to a subgroup based on a simple stratification tool and received subgroup-specific, protocolized, 4-month, exercise therapy.

MAIN OUTCOME MEASURES

Feasibility of this model of stratified exercise therapy was explored by multiple process parameters, outcome measures (physical functioning and knee pain; at baseline and 4-months follow-up) and experiences from patients and PTs.

RESULTS

From 97 potentially eligible patients, fifty patients were included and allocated to the 'high muscle strength subgroup' (n=17), 'depression subgroup' (n=4), 'obesity subgroup' (n=6) or 'low muscle strength subgroup' (n=23). Three patients dropped out during the study period. PTs provided relatively low numbers of sessions (on average 10 sessions), although exceedance of the recommended maximum number of sessions did occur frequently. We found clinically relevant improvements on physical functioning and knee pain (P<0.001 for both) for the total group. In general, the model of stratified exercise therapy was considered to be easily applicable and of added value for daily practice.

CONCLUSIONS

Our model of stratified exercise therapy seems to be feasible in primary care, although a number of limitations were reported. Future research should determine the (cost-)effectiveness of an adapted model, compared to usual, non-stratified exercise therapy.

Influence of a periodized circuit training protocol on intermuscular adipose tissue of patients with knee osteoarthritis: protocol for a randomized controlled trial

BACKGROUND

The objective of this study is to analyze the influence of a 14-week periodized circuit training protocol on patients with knee osteoarthritis (OA), in randomized intervention groups, on thigh intermuscular adipose tissue (interMAT), body composition, systemic inflammation, cartilage degradation, and its repercussion on pain, functional performance and quality of life.

METHODS

This study presents a protocol for a randomized controlled trial. Sixty selected participants diagnosed with knee OA grades II and III, 40-65 years old and BMI < 30 kg/m2, will be randomly divided into three groups:periodized circuit training, strength training, and educational protocol. The circuit training and strength training protocols consist of 14-week training protocols conducted 3 times a week. The circuit training group will perform selected exercises previously stratified as light, moderate, and intense, arranged progressively in a circuit model, the strength group will perform regular strength exercises, and the educational protocol group will participate in a 14-week protocol with lectures twice a month about healthy lifestyles. Baseline and follow-up evaluations will be conducted for thigh interMAT (computed tomography), body composition (DXA), inflammation (IL-1β, IL-6, IL-10, TNF-α, leptin, and adiponectin), and joint degradation biomarkers (uCTX-II and sCOMP), performance-based tests (30s Chair Stand Test, 40 m Fast-paced Walk Test and Stair Climb Test), quadriceps and hamstring maximal isometric voluntary contraction (MIVC), and questionnaires (WOMAC and pain catastrophizing scale). Repeated measures ANOVA will be used to compare differences between groups (circuit training X strength training X educational protocol) at the different times of assessment (baseline x follow-up or baseline x during protocol x follow-up) for each of the dependent variables. When significant main effects were found, the pots hoc Bonferroni test will be used to identify statistical differences. A significance level of 5% (p < 0.05) will be adopted.

DISCUSSION

This will be the first randomized controlled trial to assess the effects of a circuit training protocol on patients with knee OA on thigh intermuscular adipose tissue (interMAT). Given the prevalence and impact of OA and the widespread availability of this intervention, assessing the efficacy of a low-cost, non-pharmacological, and non-invasive treatment for knee OA patients has the potential for immediate and high clinical impact.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02761590 , registered in May 4, 2016.