The association between objectively measured physical activity and knee structural change using MRI

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.

Bone marrow lesions in osteoarthritis: biomarker or treatment target? A narrative review

Osteoarthritis (OA) is a leading cause of pain, functional impairment, and disability in older adults. However, there are no effective treatments to delay and reverse OA. Magnetic resonance imaging (MRI) can assess structural abnormalities of OA by directly visualizing damage and inflammatory reactions within the tissues and detecting abnormal signals in the subchondral bone marrow region. While some studies have shown that bone marrow lesions (BMLs) are one of the early signs of the development of OA and predict structural and symptomatic progression of OA, others claimed that BMLs are prevalent in the general population and have no role in the progression of OA. In this narrative review, we screened and summarized studies with different designs that evaluated the association of BMLs with joint symptoms and structural abnormalities of OA. We also discussed whether BMLs may serve as an imaging biomarker and a treatment target for OA based on existing clinical trials.

Dietary Inflammatory Index and Magnetic Resonance Imaging-Detected Knee Structural Change and Pain: A 10.7-Year Follow-up Study

OBJECTIVE

To determine whether the dietary inflammatory index (DII) scores were associated with knee structural changes and pain over a 10.7-year follow-up.

METHODS

This study used data from a prospective population-based cohort study (mean age 63 years, 51% female) in which 1,099, 875, 768, and 566 participants completed assessments at baseline, 2.6, 5.1, and 10.7 years, respectively. T1-weighted and T2-weighted magnetic resonance imaging was performed to measure cartilage volume (CV) and bone marrow lesions (BMLs) at baseline and 10.7 years. The Western Ontario and McMaster Universities Osteoarthritis Index pain questionnaire was used to measure knee pain at each visit. Pain trajectories ("minimal pain," "mild pain," and "moderate pain") were previously identified. Baseline energy-adjusted DII (E-DII) scores were calculated. Linear, log-binomial regression, linear mixed-effects modeling, and multi-nominal logistic regression were used for analyses.

RESULTS

The mean ± SD E-DII score at baseline was -0.48 ± 1.39. In multivariable analyses, higher E-DII scores were not associated with tibial CV loss or BML size increase except for medial tibial BML size increase. Higher E-DII scores were associated with a higher pain score (β = 0.21; 95% confidence interval [CI] 0.004-0.43) and an increased risk of belonging to the "moderate pain" compared to the "minimal pain" trajectory group (relative risk ratio 1.19; 95% CI 1.02-1.39).

CONCLUSION

A proinflammatory diet, as indicated by a higher DII score, may be associated with a greater pain score and higher risk of more severe pain trajectory over 10 years. However, inconsistent findings related to structural changes suggest a discordance between the potential impact of diet on structural damage and pain in knee OA.

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

Importance

It has been demonstrated that total physical activity is not associated with risk of osteoarthritis. However, the association of different types of physical activity with incident knee osteoarthritis remains unclear.

Objective

To determine whether weight-bearing recreational physical activities are associated with increased risk of incident knee osteoarthritis.

Design, Setting, and Participants

This prospective cohort study used data from the Rotterdam Study (1996 to 2009), including participants with knee x-ray measurements at baseline and follow-up examinations. Participants with knee osteoarthritis at baseline were excluded. Residents aged 45 years and older of the Ommoord district in the city of Rotterdam in The Netherlands were invited to join the Rotterdam Study (78% response rate). Analysis was conducted in June 2023.

Exposure

Total, weight-bearing, and non-weight-bearing recreational physical activities collected by questionnaires at baseline.

Main Outcomes and Measures

Incident radiographic knee osteoarthritis measured by knee x-ray was the primary outcome, and incident symptomatic knee osteoarthritis defined by x-ray and knee pain questionnaire was the secondary outcome. The association of different types of recreational physical activity with radiographic knee osteoarthritis was examined using logistic regression within generalized estimating equation framework after adjusting for potential confounders. A prespecified stratification analysis was planned on the basis of lower-limb muscle mass index (LMI) tertiles, measured by dual-energy x-ray absorptiometry.

Results

A total of 5003 individuals (2804 women [56.0%]; mean [SD] age, 64.5 [7.9] years) were included. The knee osteoarthritis incident rate was 8.4% (793 of 9483 knees) for a mean (SD) follow-up time of 6.33 (2.46) years. Higher weight-bearing activity was associated with increased odds of incident knee osteoarthritis (odds ratio [OR], 1.22; 95% CI, 1.10-1.35; P < .001), but non-weight-bearing activity was not (OR, 1.04; 95% CI, 0.95-1.15; P = .37). In the analysis stratified by LMI tertiles, the association of weight-bearing activity with incident osteoarthritis was found only among 431 patients in the lowest LMI tertile (OR, 1.53; 95% CI, 1.15-2.04; P = .003), but not among patients in the middle or high LMI tertile.

Conclusions and Relevance

The findings of this study suggest that weight-bearing activity is associated with incident knee osteoarthritis in people with low levels of lower-limb muscle mass, which might be a promising avenue for tailored advice for physical activity.

Association of smoking with cartilage loss of knee osteoarthritis: data from two longitudinal cohorts

BACKGROUND

Previous studies have been inconsistent concerning the association between smoking and risk of osteoarthritis (OA). This study aimed to explore the associations of smoking status and change in cartilage volume of OA in two longitudinal cohorts.

METHODS

Subjects from the Osteoarthritis Initiative cohort (OAI, n = 593) and the Tasmanian Older Adult Cohort (TASOAC, n = 394) were included in this study. For both cohorts, participants were classified into three groups based on their smoking status, namely 'never', 'former', and 'current' smokers. The outcome measures were the annual rate of change of tibiofemoral cartilage volume over 2 years in OAI and of tibial cartilage volume over 2.6 years in TASOAC. Potential confounders were balanced using the inverse probability of treatment weighting (IPTW) method.

RESULTS

Overall, 42.3% and 37.4% of participants were former smokers, and 5.7% and 9.3% were current smokers in the OAI and TASOAC cohorts, respectively. Compared to never smokers, neither former nor current smoking was associated with risk of the annual rate of change of tibiofemoral cartilage volume in OAI (former smoker: β=-0.068%/year, 95% confidence interval [CI] -0.824 to 0.688, p = 0.860; current smoker: β=-0.222%/year, 95% CI -0.565 to 0.120, p = 0.204) and tibial cartilage volume in TASOAC (former smoker: β = 0.001%/year, 95% CI -0.986 to 0.989, p = 0.998; current smoker: β=-0.839%/year, 95% CI -2.520 to 0.844, p = 0.329).

CONCLUSIONS

Our findings from two independent cohorts consistently showed that smoking was not associated with knee cartilage loss in older adults.

A pilot randomized controlled trial evaluating outdoor community walking for knee osteoarthritis: walk

OBJECTIVES

To determine the feasibility of a randomized controlled trial (RCT) examining outdoor walking on knee osteoarthritis (KOA) clinical outcomes and magnetic resonance imaging (MRI) structural changes.

METHOD

This was a 24-week parallel two-arm pilot RCT in Tasmania, Australia. KOA participants were randomized to either a walking plus usual care group or a usual care control group. The walking group trained 3 days/week. The primary outcome was feasibility assessed by changes being required to the study design, recruitment, randomization, program adherence, safety, and retention. Exploratory outcomes were changes in symptoms, physical performance/activity, and MRI measures.

RESULTS

Forty participants (mean age 66 years (SD 1.4) and 60% female) were randomized to walking (n = 24) or usual care (n = 16). Simple randomization resulted in a difference in numbers randomized to the two groups. During the study, class sizes were reduced from 10 to 8 participants to improve supervision, and exclusion criteria were added to facilitate program adherence. In the walking group, total program adherence was 70.0% and retention 70.8% at 24 weeks. The walking group had a higher number of mild adverse events and experienced clinically important improvements in symptoms (e.g., visual analogue scale (VAS) knee pain change in the walking group: - 38.7 mm [95% CI - 47.1 to - 30.3] versus usual care group: 4.3 mm [- 4.9 to 13.4]).

CONCLUSIONS

This study supports the feasibility of a full-scale RCT given acceptable adherence, retention, randomization, and safety, and recruitment challenges have been identified. Large symptomatic benefits support the clinical usefulness of a subsequent trial.

TRIAL REGISTRATION NUMBER

12618001097235. Key Points • This pilot study is the first to investigate the effects of an outdoor walking program on knee osteoarthritis clinical outcomes and MRI joint structure, and it indicates that a full-scale RCT is feasible. • The outdoor walking program (plus usual care) resulted in large improvements in self-reported knee osteoarthritis symptoms compared to usual care alone. • The study identified recruitment challenges, and the manuscript explores these in more details and provides recommendations for future studies.

Stepping Forward: A Scoping Review of Physical Activity in Osteoarthritis

Physical activity (PA) is recommended to mitigate the symptoms of osteoarthritis (OA); however, this modality remains an unfamiliar construct for many patients and clinicians. Moreover, there can be confusion over the nuanced differences in terminology, such as exercise, sedentary behavior, and moderate intensity. The purpose of this scoping review is to provide a basic overview of PA including terminology, summarize the importance of PA for adults with OA, and discuss current gaps in the literature. Broadly, PA is defined as any energy expenditure from skeletal muscle above a resting level, and exercise is considered a type of PA that is planned, structured, and repetitive. Robust literature shows that PA has a modest protective effect on pain, functional limitation, and disability for OA, in addition to positive effects on a broad range of outcomes from mood and affect to mortality and morbidity in the general population. We provide recommendations for which measurement instruments can be used to record PA, both from a clinical and research perspective, as well as which metrics to employ for summarizing daily activity.

Evidence Review for Preventing Osteoarthritis After an Anterior Cruciate Ligament Injury: An Osteoarthritis Action Alliance Consensus Statement

CONTEXT

The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury.

OBJECTIVE

Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps.

DESIGN

Consensus process.

SETTING

Virtual video conference calls and online voting.

PATIENTS OR OTHER PARTICIPANTS

The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds.

MAIN OUTCOME MEASURE(S)

The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation.

RESULTS

The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models.

CONCLUSIONS

This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury.

Cartilage tissue turnover increases with high- compared to low-intensity resistance training in patients with knee OA

OBJECTIVES

To investigate cartilage tissue turnover in response to a supervised 12-week exercise-related joint loading training program followed by a 6-month period of unsupervised training in patients with knee osteoarthritis (OA). To study the difference in cartilage tissue turnover between high- and low-resistance training.

METHOD

Patients with knee OA were randomized into either high-intensity or low-intensity resistance supervised training (two sessions per week) for 3 months and unsupervised training for 6 months. Blood samples were collected before and after the supervised training period and after the follow-up period. Biomarkers huARGS, C2M, and PRO-C2, quantifying cartilage tissue turnover, were measured by ELISA. Changes in biomarker levels over time within and between groups were analyzed using linear mixed models with baseline values as covariates.

RESULTS

huARGS and C2M levels increased after training and at follow-up in both low- and high-intensity exercise groups. No changes were found in PRO-C2. The huARGS level in the high-intensity resistance training group increased significantly compared to the low-intensity resistance training group after resistance training (p = 0.029) and at follow-up (p = 0.003).

CONCLUSION

Cartilage tissue turnover and cartilage degradation appear to increase in response to a 3-month exercise-related joint loading training program and at 6-month follow-up, with no evident difference in type II collagen formation. Aggrecan remodeling increased more with high-intensity resistance training than with low-intensity exercise. These exploratory biomarker results, indicating more cartilage degeneration in the high-intensity group, in combination with no clinical outcome differences of the VIDEX study, may argue against high-intensity training.

Association of Pain Phenotypes with Risk of Falls and Incident Fractures

Objective: To compare whether falls risk score and incident fracture over 10.7 years were different among three previously identified pain phenotypes. Methods: Data on 915 participants (mean age 63 years) from a population-based cohort study were studied at baseline and follow-ups at 2.6, 5.1 and 10.7 years. Three pain phenotypes were previously identified using the latent class analysis: Class 1: high prevalence of emotional problems and low prevalence of structural damage; Class 2: high prevalence of structural damage and low prevalence of emotional problems; Class 3: low prevalence of emotional problems and low prevalence of structural damage. Fractures were self-reported and falls risk score was measured using the Physiological Profile Assessment. Generalized estimating equations model and linear mixed-effects model were used to compare differences in incident fractures and falls risk score over 10.7 years between pain phenotypes, respectively. Results: There were 3 new hip, 19 vertebral, and 121 non-vertebral fractures, and 138 any site fractures during 10.7-year follow-up. Compared with Class 3, Class 1 had a higher risk of vertebral (relative risk (RR) = 2.44, 95% CI: 1.22-4.91), non-vertebral fractures (RR = 1.20, 95% CI: 1.01-1.42), and any site fractures (RR = 1.24, 95% CI: 1.04-1.46) after controlling for covariates, bone mineral density and falls risk score. Class 2 had a higher risk of non-vertebral and any site fracture relative to those in Class 3 (non-vertebral: RR = 1.41, 95% CI: 1.17-1.71; any site: RR = 1.44, 95% CI: 1.20-1.73), but not vertebral fracture. Compared with Class 3, Class 1 had a higher falls risk score at baseline (β = 0.16, 95% CI: 0.09-0.23) and over 10.7-year (β = 0.03, 95% CI: 0.01-0.04). Conclusions: Class 1 and/or Class 2 had a higher risk of incident fractures and falls risk score than Class 3, highlighting that targeted preventive strategies for fractures and falls are needed in pain population.

Association Between Walking for Exercise and Symptomatic and Structural Progression in Individuals With Knee Osteoarthritis: Data From the Osteoarthritis Initiative Cohort

OBJECTIVE

To assess the relationship between walking for exercise and symptomatic and structural disease progression in individuals with knee osteoarthritis (OA).

METHODS

We assessed a nested cohort of participants age 50 years or older within the Osteoarthritis Initiative, a community-based observational study in which subjects were enrolled between 2004 and 2006. We focused on 4 dichotomous outcomes from baseline to the 48-month visit, involving determination of the frequency of knee pain and radiographic severity of knee OA on posteroanterior semiflexed knee radiographs. The outcomes assessed included 1) new frequent knee pain, 2) worsening of radiographic severity of knee OA based on the Kellgren/Lawrence grade, 3) progression of medial joint space narrowing, and 4) improved frequent knee pain. We used a modified version of the Historical Physical Activity Survey Instrument to ascertain those subjects who reported walking for exercise after age 50 years. The survey was administered at the 96-month visit (2012-2014).

RESULTS

Of 1,212 participants with knee OA, 45% were male and 73% reported walking for exercise. The mean ± SD age was 63.2 ± 7.9 years, and the mean ± SD body mass index was 29.4 ± 4.6 kg/m2 . The likelihood of new frequent knee pain was reduced in participants with knee OA who walked for exercise as compared to those who were non-walkers (odds ratio [OR] 0.6, 95% confidence interval [95% CI] 0.4-0.8), and progression of medial joint space narrowing was less common in walkers compared to non-walkers (OR 0.8, 95% CI 0.6-1.0).

CONCLUSION

In individuals with knee OA who were age 50 years or older, walking for exercise was associated with less frequent development of knee pain. These findings support the notion that walking for exercise should be encouraged for people with knee OA. Furthermore, we offer a proof of concept that walking for exercise could be disease modifying, which warrants further study.

How Physical Activity Affects Knee Cartilage and a Standard Intervention Procedure for an Exercise Program: A Systematic Review

(1) Background: Cartilage degeneration with the natural aging process and the role of physical activity on cartilage wellness is still not clear. The objective of the present review was to understand how different physical activity interventions affect the cartilage and to propose a Standard Operating Procedure for an exercise program to maintain knee joint health; (2) Methods: Articles were collected on three different electronic databases and screened against the eligibility criteria. Results were collected in tables and the main outcomes were discussed narratively; (3) Results: A total of 24 studies have been included after the screening process and aerobic, strength, flexibility, postural balance, and mobility interventions were detected. Different protocols and types of interventions were adopted by the authors; (4) Conclusions: Physical activity interventions have mainly positive outcomes on cartilage structure, but the protocols adopted are different and various. A Standard Operating Procedure has been proposed for a physical intervention focalized on cartilage wellness that could be adopted as an intervention in the clinical setting. Furthermore, the creation of a standardized protocol wants to help scientific research to move in the same direction.

Study protocol for a randomised controlled trial of diacerein versus placebo to treat knee osteoarthritis with effusion-synovitis (DICKENS)

Background

There is an unmet need for treatments for knee osteoarthritis (OA). Effusion-synovitis is a common inflammatory phenotype of knee OA and predicts knee pain and structural degradation. Anti-inflammatory therapies, such as diacerein, may be effective for this phenotype. While diacerein is recommended for alleviating pain in OA patients, evidence for its effectiveness is inconsistent, possibly because studies have not targeted patients with an inflammatory phenotype. Therefore, we will conduct a multi-centre, randomised, placebo-controlled double-blind trial to determine the effect of diacerein on changes in knee pain and effusion-synovitis over 24 weeks in patients with knee OA and magnetic resonance imaging (MRI)-defined effusion-synovitis.

Methods

We will recruit 260 patients with clinical knee OA, significant knee pain, and MRI-detected effusion-synovitis in Hobart, Melbourne, Adelaide, and Perth, Australia. They will be randomly allocated to receive either diacerein (50mg twice daily) or identical placebo for 24 weeks. MRI of the study knee will be performed at screening and after 24 weeks of intervention. The primary outcome is improvement in knee pain at 24 weeks as assessed by a 100-mm visual analogue scale (VAS). Secondary outcomes include improvement in volumetric (ml) and semi-quantitative (Whole-Organ Magnetic Resonance Imaging Score, 0–3) measurements of effusion-synovitis using MRI over 24 weeks, and improvement in knee pain (VAS) at 4, 8, 12, 16, and 20 weeks. Intention-to-treat analyses of primary and secondary outcomes will be performed as the primary analyses. Per protocol analyses will be performed as the secondary analyses.

Discussion

This study will provide high-quality evidence to determine whether diacerein improves pain, changes disease trajectory, and slows disease progression in OA patients with effusion-synovitis. If diacerein proves effective, this has the potential to significantly benefit the substantial proportion (up to 60%) of knee OA patients with an inflammatory phenotype.

Trial registration

Australian and New Zealand Clinical Trial Registry ACTRN12618001656224. Registered on 08 October 2018.

Experiences of activity monitoring and perceptions of digital support among working individuals with hip and knee osteoarthritis - a focus group study

Background

Mobile health (mHealth), wearable activity trackers (WATs) and other digital solutions could support physical activity (PA) in individuals with hip and knee osteoarthritis (OA), but little is described regarding experiences and perceptions of digital support and the use of WAT to self-monitor PA. Thus, the aim of this study was to explore the experiences of using a WAT to monitor PA and the general perceptions of mHealth and digital support in OA care among individuals of working age with hip and knee OA.

Methods

We conducted a focus group study where individuals with hip and knee OA (n = 18) were recruited from the intervention group in a cluster-randomized controlled trial (C-RCT). The intervention in the C-RCT comprised of 12-weeks use of a WAT with a mobile application to monitor PA in addition to participating in a supported OA self-management program. In this study, three focus group discussions were conducted. The discussions were transcribed and qualitative content analysis with an inductive approach was applied.

Results

The analysis resulted in two main categories: A WAT may aid in optimization of PA, but is not a panacea with subcategories WATs facilitate PA; Increased awareness of one’s limitations and WATs are not always encouraging, and the second main category was Digital support is an appreciated part of OA care with subcategories Individualized, early and continuous support; PT is essential but needs to be modernized and Easy, comprehensive, and reliable digital support.

Conclusion

WATs may facilitate PA but also aid individuals with OA to find the optimal level of activity to avoid increased pain. Digital support in OA care was appreciated, particularly as a part of traditional care with physical visits. The participants expressed that the digital support should be easy, comprehensive, early, and continuous.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14065-0.

Recreational Physical Activity and Risk of Incident Knee Osteoarthritis: An International Meta-Analysis of Individual Participant-Level Data

OBJECTIVE

The effect of physical activity on the risk of developing knee osteoarthritis (OA) is unclear. We undertook this study to examine the relationship between recreational physical activity and incident knee OA outcomes using comparable physical activity and OA definitions.

METHODS

Data were acquired from 6 global, community-based cohorts of participants with and those without knee OA. Eligible participants had no evidence of knee OA or rheumatoid arthritis at baseline. Participants were followed up for 5-12 years for incident outcomes including the following: 1) radiographic knee OA (Kellgren-Lawrence [K/L] grade ≥2), 2) painful radiographic knee OA (radiographic OA with knee pain), and 3) OA-related knee pain. Self-reported recreational physical activity included sports and walking/cycling activities and was quantified at baseline as metabolic equivalents of task (METs) in days per week. Risk ratios (RRs) were calculated and pooled using individual participant data meta-analysis. Secondary analysis assessed the association between physical activity, defined as time (hours per week) spent in recreational physical activity and incident knee OA outcomes.

RESULTS

Based on a total of 5,065 participants, pooled RR estimates for the association of MET days per week with painful radiographic OA (RR 1.02 [95% confidence interval (95% CI) 0.93-1.12]), radiographic OA (RR 1.00 [95% CI 0.94-1.07]), and OA-related knee pain (RR 1.00 [95% CI 0.96-1.04]) were not significant. Similarly, the analysis of hours per week spent in physical activity also showed no significant associations with all outcomes.

CONCLUSION

Our findings suggest that whole-body, physiologic energy expenditure during recreational activities and time spent in physical activity were not associated with incident knee OA outcomes.

Associations Between Physical Activity, Self-reported Joint Function, and Molecular Biomarkers in Working Age Individuals With Hip and/or Knee Osteoarthritis

Objective

Previous research has suggested an association between physical activity (PA), joint function, and molecular biomarkers, but more studies are needed. The aim of this study was to explore the associations between PA or self-reported joint function and molecular biomarkers of cartilage and inflammation in individuals with hip and/or knee osteoarthritis (OA). Specific objectives were to explore the correlations between (1) the change over 3 months in self-reported PA/joint function and the change in molecular biomarkers (2) objectively measured PA and molecular biomarkers measured at 3-month follow-up.

Design

Working age participants (n = 91) were recruited from a cluster randomized controlled trial. Self-reported PA, joint function, and serum samples were collected at baseline and after 3 months. Serum concentrations of the inflammatory marker C-reactive protein (CRP) and the cartilage markers Alanine-Arginine-Glycine-Serine (ARGS)-aggrecan, cartilage oligomeric matrix protein (COMP), and type II collagen C2C were analyzed by immunoassays. Objectively measured PA (steps/day) was collected during 12 weeks from activity trackers used by 53 participants. Associations were analyzed with Spearman's rank correlation.

Results

There was a weak negative correlation between the change in self-reported PA and the change in COMP (r s = -0.256, P = .040) but not for the other molecular biomarkers. There were no correlations between the change in self-reported joint function and the change in molecular biomarkers or between the average steps/day and the molecular biomarkers at follow-up (r s ⩽ -0.206, P ⩾ .06).

Conclusion

In general, no or only weak associations were found between PA/joint function and molecular biomarkers. Future research recommends including participants with lower PA, extend the follow-up, and use a design that allows comparisons.

Prospective Association Between Inflammatory Markers and Knee Cartilage Volume Loss and Pain Trajectory

Introduction

Inflammation has been suggested to be involved in the pathogenesis of osteoarthritis and pain. We sought to explore the associations between inflammatory serum markers and magnetic resonance imaging-defined long-term structural change and pain trajectory.

Methods

A total of 169 randomly selected participants (mean age 63 years; 47% female) from a prospective cohort study were included in this study. Circulating levels of interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-α) and high-sensitivity C-reactive protein (CRP) were measured at baseline. A knee MRI scan was performed to measure cartilage volume (CV) and bone marrow lesions (BMLs) at baseline and at 10.7 years. Knee pain at four visits was measured by the WOMAC pain questionnaire, and pain trajectories were identified using group-based trajectory modelling. Linear, log-binomial and multi-nominal logistic regression were used for the analyses.

Results

IL-6 was associated with lateral but not medial tibial CV loss (β = − 0.25% per annum, per standard deviation [SD] log pg/ml; P < 0.05) in the multivariate analysis. IL-6 was also associated with a ‘Moderate pain’ trajectory (relative risk ratio 1.93 per SD log pg/ml; 95% confidence interval 1.02–3.65) relative to the ‘Minimal pain’ trajectory group. There was no significant association of TNF-α and CRP with CV loss and pain trajectory groups with the exception of a beneficial relationship between CRP and medial tibial CV loss (β = 0.20% per annum, per SD log mg/l). No association between inflammatory markers and change in BML size was observed.

Conclusions

IL-6 was independently associated with compartment-specific CV loss and worse pain trajectory, but the other markers studied were not, suggesting that components of inflammation are implicated in the pathogenesis of cartilage loss and developing a worse pain course.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-021-00341-1.

The association between incident vertebral deformities, health-related quality of life and functional impairment: a 10.7-year cohort study

We aimed to describe longitudinal changes in health-related quality of life (HRQoL) measures associated with incident vertebral deformities (VDs) over 10.7 years. Incident VDs are associated with clinically significant functional impairment in men, and reduction in overall HRQoL in older women. Increasing severity and number of incident VDs are associated with clinically meaningful functional impairment in men, but not women.

INTRODUCTION

To describe associations between incident VD and changes in HRQoL and functional ability in older adults over 10.7 years.

METHODS

Participants (n = 780) underwent whole-body dual-energy X-ray absorptiometry (DXA) scans at baseline, 2.5, 5.1 and 10.7 years later. VD was defined as ≥ 25% reduction in anterior height relative to posterior height of vertebrae from T4 to L4. An incident VD was defined as a new VD at any follow-up visit. Assessment of Quality of Life (AQoL-4D) questionnaire and Health Assessment Questionnaire-Disability Index (HAQ-DI) were used to assess HRQoL and functional impairment. Changes in AQoL and HAQ-DI associated with incident VD were analysed using multilevel mixed-effects linear regression. Log binomial regression was used to examine clinically relevant changes and effects of severity and number of VD.

RESULTS

The incidence of VD was 37% over 10.7 years. In women, incident VDs were associated with annual reduction in AQoL utility score (β = -0.005, 95% CI -0.008 to -0.002). Men had increased risk of clinically significant reduction in HAQ-DI (IRR = 1.76, 95% CI 1.07-2.89). Men had increased risk of clinically important functional impairment with increasing severity (IRR 1.76, 95% CI 1.04-2.95 for mild vs IRR 1.98, 95% CI 1.13-3.47 for moderate to severe VD) as well as number of incident VD (IRR 1.85, 95% CI 1.17-2.93 for one vs IRR 1.88, 95% CI 0.94-3.78 for ≥ 2 VDs). Such associations were not observed in women.

CONCLUSIONS

Incident VDs are associated with clinically significant functional impairment in men, and reduction in overall HRQoL in older women. Increasing severity and number of incident VDs are associated with clinically meaningful functional impairment in men, but not women.

Marathon Running Increases Synthesis and Decreases Catabolism of Joint Cartilage Type II Collagen Accompanied by High-Energy Demands and an Inflamatory Reaction

Objective: To determine the effect of marathon running on serum levels of inflammatory, high energy, and cartilage matrix biomarkers and to ascertain whether these biomarkers levels correlate.

Design: Blood samples from 17 Caucasian male recreational athletes at the Barcelona Marathon 2017 were collected at the baseline, immediately and 48 h post-race. Serum C reactive protein (CRP), creatin kinase (CK), and lactate dehydrogenase (LDH) were determined using an AU-5800 chemistry analyser. Serum levels of hyaluronan (HA), cartilage oligomeric matrix protein (COMP), aggrecan chondroitin sulphate 846 (CS846), glycoprotein YKL-40, human procollagen II N-terminal propeptide (PIINP), human type IIA collagen N-propeptide (PIIANP), and collagen type II cleavage (C2C) were measured by sandwich enzyme-linked immune-sorbent assay (ELISA).

Results: Medians CK and sLDH levels increased (three-fold, two-fold) post-race [429 (332) U/L, 323 (69) U/L] (p < 0.0001; p < 0.0001) and (six-fold, 1.2-fold) 48 h post-race [658 (1,073) U/L, 218 (45) U/L] (p < 0.0001; p < 0.0001). Medians CRP increased (ten-fold) after 48 h post-race [6.8 (4.1) mg/L] (p < 0.0001). Mean sHA levels increased (four-fold) post-race (89.54 ± 53.14 ng/ml) (p < 0.0001). Means PIINP (9.05 ± 2.15 ng/ml) levels increased post-race (10.82 ± 3.44 ng/ml) (p = 0.053) and 48 h post-race (11.00 ± 2.96 ng/ml) (p = 0.001). Mean sC2C levels (220.83 ± 39.50 ng/ml) decreased post-race (188.67 ± 38.52 ng/ml) (p = 0.002). In contrast, means COMP, sCS846, sPIIANP, and median sYKL-40 were relatively stable. We found a positive association between sCK levels with sLDH pre-race (r = 0.758, p < 0.0001), post-race (r = 0.623, p = 0.008) and 48-h post-race (r = 0.842, p < 0.0001); sHA with sCRP post-race vs. 48 h post-race (r = 0.563, p = 0.019) and sPIINP with sCK pre-race vs. 48-h post-race (r = 0.499, p = 0.044) and with sLDH 48-h pre-race vs. post-race (r = 0.610, p = 0.009) and a negative correlation of sPIIANP with sCRP 48-h post-race (r = −0.570, p = 0.017).

Conclusion: Marathon running is an exercise with high-energy demands (sCK and sLDH increase) that provokes a high and durable general inflammatory reaction (sCRP increase) and an immediately post-marathon mechanism to protect inflammation and cartilage (sHA increase). Accompanied by an increase in type II collagen cartilage fibrils synthesis (sPIINP increase) and a decrease in its catabolism (sC2C decrease), without changes in non-collagenous cartilage metabolism (sCOMP, sC846, and sYKL-40). Metabolic changes on sPIINP and sHA synthesis may be related to energy consumption (sCK, sLDH) and the inflammatory reaction (sCRP) produced.

Clinical relevance of MRI knee abnormalities in Australian rules football players: a longitudinal study

Background/Aim

The clinical relevance of MRI knee abnormalities in athletes is unclear. This study aimed to determine the prevalence of MRI knee abnormalities in Australian Rules Football (ARF) players and describe their associations with pain, function, past and incident injury and surgery history.

Methods

75 male players (mean age 21, range 16–30) from the Tasmanian State Football League were examined early in the playing season (baseline). History of knee injury/surgery and knee pain and function were assessed. Players underwent MRI scans of both knees at baseline. Clinical measurements and MRI scans were repeated at the end of the season, and incident knee injuries during the season were recorded.

Results

MRI knee abnormalities were common at baseline (67% bone marrow lesions, 16% meniscal tear/extrusion, 43% cartilage defects, 67% effusion synovitis). Meniscal tears/extrusion and synovial fluid volume were positively associated with knee symptoms, but these associations were small in magnitude and did not persist after further accounting for injury history. Players with a history of injury were at a greater risk of having meniscal tears/extrusion, effusion synovitis and greater synovial fluid volume. In contrast, players with a history of surgery were at a greater risk of having cartilage defects and meniscal tears/extrusion. Incident injuries were significantly associated with worsening symptoms, BML development and incident meniscal damage.

Conclusions

MRI abnormalities are common in ARF players, are linked to a previous knee injury and surgery history, as well as incident injury but do not dictate clinical symptomatology.

Daily Walking and the Risk of Knee Replacement Over 5 Years Among Adults With Advanced Knee Osteoarthritis in the United States

OBJECTIVE

To examine the association of the volume and intensity of daily walking at baseline with the risk of knee replacement (KR) over 5 years in adults with advanced structural knee osteoarthritis.

DESIGN

Prospective, longitudinal, and multicenter observational study.

SETTING

Osteoarthritis Initiative study with follow-up from 2008-2015.

PARTICIPANTS

Community-dwelling adults with or at risk of knee osteoarthritis were recruited from 4 sites in the United States (N=516; mean age, 67.7±8.6y; body mass index, 29.3±4.7 kg/m2; 52% female). We included participants with advanced structural disease, without KR and had valid daily walking data (quantified using Actigraph GT1M), at baseline.

INTERVENTIONS

Not applicable.

MAIN OUTCOMES

KR. Walking volume was measured as steps/day and intensity as minutes/day spent not walking (0 steps/min) and walking at very light (1-49 steps/min), light (50-100 steps/min), or moderate (>100 steps/min) intensities. To examine the relationship of walking volume and intensity with the risk of KR, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) adjusting for covariates.

RESULTS

Of 516 adults with advanced structural disease, 88 received a KR over 5 years (17%). Walking an additional 1000 steps/d was not associated with the risk of KR (adjusted HR=0.95; 95% CI, 0.84-1.04). Statistically, replacing 10 min/d of very light and light walking with 10 min/d of moderate walking reduced the risk of KR incidence by 35% and 37%, respectively (adjusted HR=0.65, 95% CI, 0.45-0.94, for very light and adjusted HR=0.63; 95% CI, 0.40-1.00, for light).

CONCLUSIONS

Daily walking volume and intensity did not increase KR risk over 5 years and may be protective in some cases in adults with advanced structural knee osteoarthritis.

Using Step Counts to Prescribe Physical Activity: What Is the Optimal Dose?

ABSTRACT

An activity goal of 10,000 steps per day is widely known but was not initially developed based on scientific evidence. The last several years have seen an increase in both the availability of consumer-based step counting devices and research examining the link between daily step counts and various health outcomes. Daily step counts are an intuitive metric of physical activity and are useful for goal-setting and motivating behavioral change. This article reviews the current evidence for daily step counts as related to common health conditions to determine activity goals to prescribe to patients, and also discusses factors to consider when counseling patients on physical activity.

Muscle function, quality, and relative mass are associated with knee pain trajectory over 10.7 years

ABSTRACT

Periarticular muscle plays an important role in the pathogenesis of musculoskeletal pain. We recently reported that pain population consists of distinct subgroups of which the causes and mechanisms may differ. This study aimed to examine the association of lean mass, muscle strength, and quality with 10.7-year pain trajectory. Nine hundred forty-seven participants from a population-based cohort study were analysed. Dual-energy X-ray absorptiometry was used to assess lean and fat mass. Leg strength, knee extensor strength, and lower-limb muscle quality were measured/calculated. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index pain questionnaire. Radiographic knee osteoarthritis was assessed by X-ray. Three distinct pain trajectories were identified: "Minimal pain" (53%), "Mild pain" (34%), and "Moderate pain" (13%). Higher total and lower-limb lean mass were associated with an increased risk of "Mild pain" and "Moderate pain" trajectories relative to the "Minimal pain" trajectory group, but these associations became nonsignificant after further adjustment for fat mass. Total lean mass percentage was associated with a lower risk of "Mild pain" (relative risk ratio [RRR]: 0.95, 95% confidence interval 0.92-0.98) and "Moderate pain" trajectory (RRR: 0.92, 95% confidence interval 0.87-0.96). Greater leg and knee extensor strength and muscle quality were associated with "Mild pain" and "Moderate pain" trajectories (RRR: 0.52-0.65, all P < 0.05). Similar results were found in those with radiographic knee osteoarthritis. Higher lower-limb muscle strength and quality, and relative lean mass, are associated with a reduced risk of severe knee pain trajectories, suggesting that improving muscle function and composition may protect against persistent unfavourable knee pain courses.

Sleep disturbance and bone mineral density, risk of falls and fracture: Results from a 10.7-year prospective cohort study

Sleep problems are common in the general population and have been linked to bone health, falls risk and fracture. However, longitudinal studies on sleep-bone health outcomes are lacking and no study has investigated whether an increased risk of fracture is attributable to sleep-related low bone mineral density (BMD) and an increased risk of falls. This study was designed to examine the associations of sleep disturbance with bone mineral density (BMD), risk of falls and fractures over 10.7 years. The analyses were performed in a population-based cohort study with 1099 participants (mean age 62.9 years) enrolled at baseline, and 875, 768 and 563 participants traced at a mean follow-up of 2.6, 5.1 and 10.7 years, respectively. At each visit, self-reported sleep disturbance was recorded. BMD (by dual-energy x-ray absorptiometry), falls risk score and fracture were measured at each visit. The short-form Physiological Profile Assessment was used to measure falls risk score expressed as Z-score. Fractures were self-reported. Mixed-effects model and generalized estimating equations were used for the analyses. In multivariable analysis, there was a dose-response relationship between the extent of sleep disturbance and falls risk score with the strongest association in those reporting the worst sleep disturbance (β = 0.15/unit; 95%CI 0.02-0.28). The worst sleep disturbance was associated with an increased risk of any (relative risk [RR] 1.30/unit; 95%CI 1.01-1.67) and vertebral fracture (RR 2.41/unit; 95%CI 1.00-5.80) compared with those reporting no interrupted sleep. Women but not men with sleep disturbance had a higher risk of vertebral fracture (RR: 2.07 to 6.02, P < 0.05). These were independent of covariates, hip BMD and falls risk. There was no statistically significant association between sleep disturbance and BMD at the hip, spine or total body. Sleep disturbance was independently associated with a greater falls risk score and an increased risk of fractures. Further research is needed to confirm and identify underlying mechanisms for these associations.

The Longitudinal Relationship Between Physical Activity and Joint Space Narrowing: 48-Month Follow-Up Data from the Osteoarthritis Initiative

OBJECTIVE

To determine whether amount of physical activity (PA) is a determinant of joint space narrowing (JSN) worsening over 48-months in participants with knee osteoarthritis (OA).

METHODS

Data were obtained from the Osteoarthritis Initiative. PA, measured using the Physical Activity Scale for the Elderly (PASE), was defined as the mean value of the annual measurements conducted prior to development of worsening JSN. Worsening JSN was defined as at least a partial grade increase in OARSI JSN score over 48 months, in comparison with baseline. Restricted cubic spline (RCS) function was used to group participants based on the linear association between PA and JSN worsening. A pooled logistic regression model was used to evaluate the association between PA and JSN worsening adjusted for confounders.

RESULTS

2,167 participants were included. In total, 625 (28.8%) participants had JSN worsening over 48 months. Compared with PASE score of 140-180, PASE scores of 100-140 and >220 associated with an increased risk of JSN worsening in men with OR (95% CI) of 1.73 (1.07, 2.81) and 1.83 (1.14, 2.93) respectively. Similarly, in participants with Kellgren and Lawrence grade 2, compared with a PASE score of 140-180, PASE score of <100 and >220 were associated with increased risks of JSN worsening, with OR (95% CIs) of 1.69 (1.13, 2.54) and 1.64 (1.05, 2.56) respectively.

CONCLUSION

Compared to moderate PA, higher or lower amounts of PA are associated with elevated risk for JSN worsening in men and in participants with KL grade 2 knees.

Lateral Coronal Bowing of Femur and/or Tibia Amplifies the Varus Malalignment of Lower Limb as well as Increases Functional Disability in Patients with Knee Osteoarthritis

PURPOSE

In the present study, we aimed at assessing the effect of femoral and tibial coronal bowing on varus malalignment and Oxford knee score (OKS) at different grades of knee osteoarthritis (OA).

MATERIALS AND METHODS

This prospective observational study was conducted at a tertiary referral centre in New Delhi, India. Consecutive patients presenting to the "knee OA" outpatient clinics were invited to take part in the study conducted over a 12-month period. All consented patients underwent long-leg standing alignment radiographs using standardised technique and patient reported knee pain and function were recorded using Oxford knee score. The following radiological parameters were measured from weight-bearing long-leg radiographs of 824 varus aligned limbs via a morphometric software (Matlab R2009a) (1) hip-knee-ankle angle (HKAA), (2) femoral bowing, (3) tibial bowing. The knees were graded according to Kellegren and Lawrence grade (K&L) and OKS was recorded. 3 groups of HKAA were made based on the angle, A (0° to - 3°), B (- 3° to - 10°) and C (< - 10°). Both the femoral and tibial bow were also categorized into three groups depending upon the angle; in-range (- 2° to + 2°), varus (< - 2°), valgus (> + 2°).

RESULTS

The mean (± SD) of HKAA, femoral bow and tibial bow of the whole cohort was - 6.97° ± 5.64°, - 1.54° ± 4.31° and - 1.96° ± 3.5°, respectively. An increase in the lateral bow of both femur and tibia was seen with an increase in the severity of OA. A consequent increase in the varus malalignment was observed with an increase in the lateral bow of both femur as well as the tibia at all grades of OA, with significant correlation observed between HKAA with Femoral bowing and HKAA with tibial bowing. The mean OKS for femoral bow, in-range, varus and valgus was 30.6 ± 11.5, 21.3 ± 11.5 and 35.3 ± 11.4, respectively, and for tibial bow, in-range, varus and valgus was 27.6 ± 11.5, 26. ± 11.5 and 28 ± 11.4, respectively. The difference in the mean OKS was observed to be significant when the varus bow group was compared to in range as well as valgus group (p < 0.01) for both femur and tibia for all the grades of OA.

CONCLUSION

The present study shows a significant correlation between varus malalignment and the bowing of extremities. Varus coronal bowing of both femur and tibia were seen to have significantly lower mean OKS as compared to valgus bowing or in-range bowing at all grades of knee OA.

Sleep Disturbance and Its Association with Pain Severity and Multisite Pain: A Prospective 10.7-Year Study

INTRODUCTION

Sleep disturbance is often comorbid with chronic pain disorders, with emerging evidence suggesting a stronger effect of sleep disturbance on pain than vice versa; however, few studies have evaluated the long-term associations between sleep disturbance and pain. This study was to examine the associations of sleep disturbance with knee pain severity, number of painful sites (NPS) and persistent pain in a 10.7-year cohort study.

METHODS

A total of 1099 community-dwelling older adults (age mean ± SD, 63 ± 7.5 years; 51% female) were recruited and followed up at 2.6, 5.1 and 10.7 years later. Data on demographics, body mass index, physical activity and comorbidities were collected. At each time point, sleep disturbance, knee pain severity and NPS were assessed by using questionnaires. Multisite pain (MSP) was defined as NPS ≥ 2. Persistent knee pain or MSP was defined as having knee pain or MSP at all time points, respectively. Multivariable mixed-effects models and log-binomial regression were applied.

RESULTS

In multivariable analyses, sleep disturbance was associated with greater knee pain severity (β 0.91/unit, 95% CI 0.70-1.11) and more NPS [(relative risk (RR) 1.10/unit, 95% CI 1.07-1.14] in a dose-response manner. Persistent sleep disturbance was associated with persistent knee pain (RR 1.90, 1.26-2.87) and MSP (RR 1.29, 1.07-1.56). Persistent knee pain and MSP were also associated with persistent sleep disturbance (knee pain: RR = 1.99; MSP: RR = 2.71, both P < 0.05).

CONCLUSIONS

Sleep disturbance was independently associated with greater pain severity and NPS in a dose-response manner. A reciprocal relationship between persistent sleep disturbance and persistent pain suggests treating either problem could help the other.

Setting up distinctive outcome measures for each osteoarthritis phenotype

Osteoarthritis (OA) is an evolving chronic joint disease with a huge global impact. Given the intricate nature of the etiopathogenesis and subsequent high heterogeneity in the clinical course of OA, it is crucial to discriminate between etiopathogenic endotypes and clinical phenotypes, especially in the early stages of the disease. In this sense, we propose that an OA phenotype should be properly assessed with a set of outcome measures including those specifically related to the main underlying pathophysiological mechanisms. Thus, each OA phenotype can be related to different and clinically meaningful outcomes. OA phenotyping would lead to an adequate patient stratification in well-designed clinical trials and the discovery of precise therapeutic approaches. A significant effort will be required in this field in light of inconclusive results of clinical trials of tissue-targeting agents for the treatment of OA.

Comparison of radiographic and MRI osteoarthritis definitions and their combination for prediction of tibial cartilage loss, knee symptoms and total knee replacement: a longitudinal study

OBJECTIVE

To describe the value of radiographic- and magnetic resonance imaging (MRI)-defined tibiofemoral osteoarthritis (ROA and MRI-OA, respectively) and in combination for predicting tibial cartilage loss, knee pain and disability and total knee replacement (TKR) in a population-based cohort.

DESIGN

A radiograph and 1.5T MRI of the right knee was performed. ROA and MRI-OA at baseline were defined according to the Osteoarthritis Research Society International atlas and a published Delphi exercise, respectively. Tibial cartilage volume was measured over 2.6 and 10.7 years. Knee pain and disability were assessed at baseline, 2.6, 5.1 and 10.7 years. Right-sided TKRs were assessed over 13.5 years.

RESULTS

Of 574 participants (mean 62 years, 49% female), 8% had ROA alone, 15% had MRI-OA alone, 13% had both ROA and MRI-OA. Having ROA (vs. no ROA) and MRI-OA (vs. no MRI-OA) predicted greater tibial cartilage loss over 2.6 years (-75.9 and -86.4 mm³/year) and higher risk of TKR over 13.5 years (Risk Ratio [RR]: 15.0 and 10.9). Only MRI-OA predicted tibial cartilage loss over 10.7 years (-7.1 mm³/year) and only ROA predicted onset and progression of knee symptoms (RR: 1.32-1.88). In participants with both MRI-OA and ROA, tibial cartilage loss was the greatest (over 2.6 years: -116.1 mm³/year; over 10.7 years: -11.2 mm³/year), and the onset and progression of knee symptoms (RR: 1.75-2.89) and risk of TKR (RR: 50.9) were the highest.

CONCLUSIONS

The Delphi definition of MRI-OA is not superior to ROA for predicting structural or symptomatic OA progression but, combining MRI-OA and ROA has much stronger predictive validity.

Using Cumulative Load to Explain How Body Mass Index and Daily Walking Relate to Worsening Knee Cartilage Damage Over Two Years: The MOST Study

OBJECTIVE

Knee cartilage damage is often linked to mechanical overloading. However, cartilage requires mechanical load to remain healthy, suggesting that underloading may be detrimental. This study was undertaken to examine knee overloading and underloading by defining cumulative load as the joint effects of body mass index (BMI) and daily walking, and examine the relationship between cumulative load and worsening cartilage damage over 2 years.

METHODS

We used data from the Multicenter Osteoarthritis Study. Steps/day, measured by accelerometry, and BMI were calculated at the 60-month visit. Cartilage damage on magnetic resonance imaging was semiquantitatively scored using the Whole-Organ Magnetic Resonance Imaging Score (WORMS) at the 60-month and 84-month visits; worsening damage was defined as increased WORMS between visits. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were calculated using binomial regression, with adjustment for potential confounders.

RESULTS

Our study included 964 participants, 62% of whom were female, with a mean ± SD age of 66.9 ± 7.5 years. Participants had a mean ± SD BMI of 29.7 ± 4.8 kg/m² and walked a mean ± SD of 7,153 ± 2,591 steps/day. Participants who walked a moderate number of steps/day (6,000-7,900) or a high number of steps/day (>7,900) and had a high BMI (>31 kg/m² ) had a greater risk of worsening medial tibiofemoral (TF) damage (RR 2.83 [95% CI 1.46-5.48] and RR 2.61 [95% CI 1.50-4.54], respectively) compared with those who walked similar steps/day and had a low BMI (18-27 kg/m² ). Participants with a low number of steps/day (<6,000) and a low BMI had a greater risk of worsening medial TF and lateral patellofemoral (PF) damage (RR 2.03 [95% CI 1.06-3.92] and RR 2.28 [95% CI 1.06-4.85], respectively) compared with those who walked a high number of steps/day and had a low BMI. Effect estimates for other compartments of the knee did not reach statistical significance.

CONCLUSION

This study provides preliminary evidence that both overloading and underloading may be detrimental to medial TF cartilage, and underloading may be detrimental to lateral PF cartilage.

The association of subchondral and systemic bone mineral density with osteoarthritis-related joint replacements in older adults

OBJECTIVE

To describe the association of subchondral and systemic bone mineral density (BMD) with knee and hip replacements (KR and HR, respectively) due to osteoarthritis.

DESIGN

1,095 participants (mean age 63 years, 51% female) were included. At baseline, subchondral BMD of the medial and lateral tibia in three regions of interest (ROI) for the right knee, and systemic BMD of the lumbar spine, femoral neck, total hip and whole-body, were measured using dual-energy X-ray absorptiometry. Subchondral BMD of the hip was not measured. Competing risk regression models were used to estimate sub-distribution hazard ratios (SHRs) of KR/HR per one standard deviation (SD) higher in BMD measures, with adjustment of potential confounders.

RESULTS

Over 12.2 years, 79 (7.2%) participants underwent a KR and 56 (5.1%) an HR due to osteoarthritis. For the right side, medial subchondral BMD in ROI-3 was associated with an increased risk of KR (SHR 1.95 per SD; 95% Confidence Interval [CI], 1.57 to 2.43). In contrast, systemic BMD was not associated with the risk of KR, but higher BMD at the lumbar spine (1.42, 1.07 to 1.88) and whole-body (1.29, 1.00 to 1.66) were associated with an increased risk of HR at both sides.

CONCLUSIONS

Subchondral BMD is positively associated with an increased risk of KR and systemic BMD with an increased risk of HR, suggesting a role of BMD in the progression of osteoarthritis.

Do Knee Pain Phenotypes Have Different Risks of Total Knee Replacement?

Pain is the main impetus for osteoarthritis (OA) patients to seek healthcare including joint replacement. The pain experience in OA is heterogeneous and affected by factors across multiple domains—peripheral, psychological, and neurological. This indicates the existence of homogenous subgroups/phenotypes within OA patients with pain. We recently identified three pain phenotypes using a wide spectrum of pain-related factors, including structural damage on magnetic resonance imaging (MRI), emotional problems, number of painful sites, sex, body mass index, education level and comorbidities (i.e., Class 1: high prevalence of emotional problems and low prevalence of structural damage (25%); Class 2: low prevalence of emotional problems and high prevalence of structural damage (20%); Class 3: low prevalence of emotional problems and low prevalence of structural damage (55%)). This study was to examine whether the total knee replacement (TKR) risk over 12 years was different among these three pain phenotypes. Data on 963 participants (mean age 62.8 ± 7.4 years) from a population-based cohort study were utilised. Data on socio-demographic, psychological and comorbidities were collected. MRI of the right knee structural pathology was performed. TKR history was ascertained by linking to the Australian Orthopedic Association National Joint Replacement Registry. Latent class analysis and the Cox proportional hazards model were applied for the analysis. During the follow-up period, 41 right and 44 left TKRs in 67 participants were identified. In multivariable analyses, participants in Class 1 and 2 had a higher risk of having a TKR (Class 1 vs. Class 3, HR (hazard ratio) 4.81, 95%CI (confidence interval) 2.33–9.93; Class 2 vs. Class 3, HR 9.23, 95%CI 4.66–18.30). These associations were stronger in the imaged right knee but were also significant in the left knee. Participants within distinct pain phenotypes have different risks of TKR, suggesting that the identified phenotypes reflect distinct clinical subgroups with different prognoses. The risk for TKR was higher in Class 1 than that in Class 3, suggesting that pain/emotional status is a stronger driver for TKR than structural damage, and that selecting patients for TKR needs to be optimized in clinical practice.

Identifying subgroups of community-dwelling older adults and their prospective associations with long-term knee osteoarthritis outcomes

OBJECTIVES

To identify subgroups of community-dwelling older adults and to assess their longitudinal associations with long-term osteoarthritis (OA) outcomes.

METHODS

1046 older adults aged 50-80 years were studied. At baseline, body mass index (BMI), pedometer-measured ambulatory activity (AA), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) determined knee pain and information on comorbidities were obtained. Tibial cartilage volume and bone-marrow lesions (BMLs) were assessed using MRI at baseline and 10 years and total knee replacements (TKR) by data linkage to the Australian Orthopaedic Association National Joint Replacement Registry. Latent class analysis was used to determine participant subgroups, considering baseline BMI, AA, pain and comorbidities, and linear mixed-effects or log-binomial models were used to assess the associations.

RESULTS

Three subgroups/classes were identified: subgroup 1 (43%): Normal/overweight participants with higher AA, lower pain and lower comorbidities; subgroup 2 (32%): Overweight participants with lower AA, mild pain and higher comorbidities; subgroup 3 (25%): Obese participants with lower AA, mild pain and higher comorbidities. Subgroup 3 had greater cartilage volume loss (β - 60.56 mm³, 95% CI - 105.91, - 15.21) and a higher risk of TKR (RR 3.19, 95% CI 1.75, 5.81), compared to subgroup 1. Subgroup 2 was not associated with cartilage volume change (β 13.06 mm³, 95% CI - 30.87, 57.00) or risk of TKR (RR 1.16, 95% CI 0.56, 2.36), compared to subgroup 1. Subgroup membership was not associated with worsening BMLs.

CONCLUSIONS

Our findings suggest the existence of homogeneous subgroups of participants and support the utility of identifying patterns of characteristics/risk factors that may cluster together and using them to identify subgroups of people who may be at a higher risk of developing and/or progressing OA. Key Points • Complex interplay among characteristics/factors leads to conflicting evidence between ambulatory activity and knee osteoarthritis. • Distinct subgroups are identifiable based on ambulatory activity, body mass index, knee pain, and comorbidities. • Identifying subgroups can be used to determine those who are at risk of developing/progressing osteoarthritis.

Metabolic syndrome and trajectory of knee pain in older adults

OBJECTIVES

To examine the association of metabolic syndrome (MetS) and its components with knee pain severity trajectories.

METHODS

Data from a population-based cohort study were utilised. Baseline blood pressure, glucose, triglycerides and high-density lipoprotein (HDL) cholesterol were measured. MetS was defined according to the National Cholesterol Education Program-Adult Treatment Panel III criteria. Radiographic knee osteoarthritis (ROA) was assessed by X-ray. Pain severity was measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain questionnaire at each time-point. Group-based trajectory modelling was used to identify pain trajectories and multi-nominal logistic regression was used for analysis. Mediation analysis was performed to assess whether body mass index (BMI)/central obesity mediated the association between MetS, its components and pain trajectories.

RESULTS

Among 985 participants (Mean ± SD age: 62.9 ± 7.4, 50% female), 32% had MetS and 60% had ROA. Three pain trajectories were identified: 'Minimal pain' (52%), 'Mild pain' (33%) and 'Moderate pain' (15%). After adjustment for potential confounders, central obesity increased risk of belonging to both 'Mild pain' and 'Moderate pain' trajectories as compared to the 'Minimal pain' trajectory group, but MetS [relative risk ratio (RRR): 2.26, 95%CI 1.50-3.39], hypertriglyceridemia (RRR: 1.75, 95%CI 1.16-2.62) and low HDL (RRR: 1.67, 95%CI 1.10-2.52) were only associated with 'Moderate pain' trajectory. BMI/central obesity explained 37-70% of these associations. Results were similar in those with ROA.

CONCLUSION

MetS and its components are predominantly associated with worse pain trajectories through central obesity, suggesting that the development and maintenance of worse pain trajectories may be caused by MetS.

Effects of Physical Activity in Knee and Hip Osteoarthritis: A Systematic Umbrella Review

INTRODUCTION

We conducted a systematic umbrella review to evaluate the literature relating to effects of physical activity on pain, physical function, health-related quality of life, comorbid conditions and osteoarthritis (OA) structural disease progression in individuals with lower-extremity OA.

METHODS

Our primary search encompassed 2011 to February 2018 for existing systematic reviews (SR), meta-analyses (MA) and pooled analyses dealing with physical activity including exercise (not mixed with any other intervention and compared to a no-activity control group). A supplementary search encompassed 2006 to February 2018 for original research related to physical activity (including exercise) and lower limb OA progression. Study characteristics were abstracted, and risk of bias was assessed.

RESULTS

Physical activity decreased pain and improved physical function (strong evidence) and improved health-related quality of life (moderate evidence) among people with hip or knee OA relative to less active adults with OA. There was no evidence to suggest accelerated OA progression for physical activity below 10,000 steps per day. Both physical activity equivalent to the 2008 Physical Activity Guidelines for Americans (150 min·wk of moderate-intensity exercise in bouts ≥10 min) and lower levels of physical activity (at least 45 total minutes per week of moderate-intensity) were associated with improved or sustained high function. No SR/MA addressing comorbid conditions in OA were found. Measurable benefits of physical activity appeared to persist for periods of up to 6 months following cessation of a defined program.

CONCLUSIONS

People with lower-extremity OA should be encouraged to engage in achievable amounts of physical activity, of even modest intensities. They can choose to accrue minutes of physical activity throughout the entire day, irrespective of bout duration, and be confident in gaining some health and arthritis-related benefits.

Association of age, sex and BMI with the rate of change in tibial cartilage volume: a 10.7-year longitudinal cohort study

Background

To describe the association of age, sex and body mass index with the rate of change of tibial knee cartilage volume over 10.7 years in a community-based sample of older adults.

Methods

Four hundred and eighty-one participants (49% female, mean age 60.8 years [range 51.1–79.7], 49% had knee pain and 58% radiographic osteoarthritis) were included. Tibial cartilage volume of the right knee was assessed on T1-weighted fat-suppressed 1.5 T MRI at baseline and 10.7 years. Data analyses were performed using linear regression models.

Results

The average rate of loss of cartilage volume was 1.2%/year (range 0.2–3.9%) with all participants losing cartilage volume over the study period. There was a significant association between age and loss of tibial cartilage volume in the medial (0.023%/year, 95% confidence interval [CI] 0.010 to 0.036%, p < 0.001), lateral (0.013%/year, 95% CI 0.003 to 0.023%, p = 0.012) and total tibia (0.018%/year, 95% CI 0.009 to 0.026%, p < 0.001). Higher body mass index at baseline and increases in body mass index over time were associated with a greater tibial cartilage loss at the medial (body mass index at baseline 0.040%/year, 95% CI 0.022 to 0.058%, p < 0.001; increases in body mass index 0.055%/year, 95% CI 0.018 to 0.093%, p = 0.004) but not lateral compartment. No evidence of non-linear relationships was observed. Compared to males, females lost more lateral tibial cartilage with increasing age (0.023%/year, 95% CI 0.003 to 0.043%, p = 0.024 for interaction).

Conclusions

Tibial cartilage volume declines at a faster rate with increasing age and body mass index in both males and females, particularly in the medial compartment. In contrast to the low rate of change in radiographs, our findings suggest that cartilage loss at the tibia is universal in this age group.

Differentiating knee pain phenotypes in older adults: a prospective cohort study

Objective

To identify and validate knee pain phenotypes in an older population across different pain-related domains over 10.7 years.

Methods

A total of 963 participants (mean age 63 years) from a population-based older adult cohort study were studied at baseline and followed up at 2.6 (n = 875), 5.1 (n = 768) and 10.7 years (n = 563). Baseline demographic, psychological, lifestyle and comorbidities data were obtained and MRI was performed to measure knee structural pathology. WOMAC pain and pain at multiple sites were assessed by questionnaires at each time-point. Latent class analysis was used to identify knee pain phenotypes, considering sex, BMI, emotional problems, education level, comorbidities, number of painful sites and knee structural pathology.

Results

Three pain phenotypes were identified: Class 1: high prevalence of emotional problems and low prevalence of structural damage (25%); Class 2: high prevalence of structural damage and low prevalence of emotional problems (20%); Class 3: low prevalence of emotional problems and low prevalence of structural damage (55%). Participants within Class 1 and 2 had greater BMI, more comorbidities, a higher prevalence of radiographic knee OA and knee structural pathology compared with Class 3. Furthermore, compared with Class 2 and 3, WOMAC pain and number of painful sites were consistently greater at each time-point over 10.7 years in Class 1. Results were similar when the analyses were restricted to participants with radiographic knee OA.

Conclusion

Psychological and structural factors interact with each other to exacerbate pain perception, suggesting that tailored treatment approaches for older people with knee pain in clinical practice are needed.

Pain at Multiple Sites Is Associated With Prevalent and Incident Fractures in Older Adults

Musculoskeletal pain is common and typically occurs at multiple sites. Pain has been shown to be associated with falls risk; however, whether an increased risk for falls associated with multisite pain (MSP) translates into an increased risk of fractures has not been investigated. This study aimed to examine the association of number of painful sites with prevalent and incident fractures. Data from a longitudinal population-based study of older adults (mean age 63 years) were utilized. Follow-up was performed at 2.6, 5.1, and 10.7 years later, respectively. Presence/absence of pain at the neck, back, hands, shoulders, hips, knees, and feet was assessed by questionnaire at baseline. Participants were classified into three groups according to the total number of painful sites: zero to two, three to four, and five to seven. Fractures were self-reported at each time point. BMD was measured by DXA. Falls risk was calculated based on the Short-Form Physiological Profile Assessment. Log-binomial regression was used for the analyses. There were 450 fractures at baseline and 154 new fractures reported during a mean follow-up period of 10.7 years (range 9.2 to 12.5 years). In multivariable analyses, number of painful sites was associated with prevalent fractures at any and nonvertebral site. Furthermore, participants with five to seven painful sites had an increased risk of incident fractures at any site (RR 1.69; 95% CI, 1.13 to 2.53); major site, including the femur, radius, ulnar, vertebral, rib, and humerus (RR 2.17; 95% CI 1.12 to 4.22); and vertebral site (RR 6.44, 95% CI, 1.64 to 25.33) compared with those with pain at zero to two sites. These associations remained statistically significant after further adjustment for falls risk and BMD. Pain at multiple sites was associated with incident fracture risk in a dose-response manner, suggesting that widespread pain is an independent contributor to fracture risk. The potential for pain management in fracture prevention warrants further exploration. © 2019 American Society for Bone and Mineral Research.

Physical Activity and Worsening of Radiographic Findings in Persons With or at Higher Risk of Knee Osteoarthritis

OBJECTIVE

The benefits of physical activity among persons with or at higher risk for knee osteoarthritis are well established. However, activity levels in this population are low, in part due to concern that activity will damage the knee joint. We hypothesized that sedentary and moderate-vigorous physical activity are each associated with greater risk of radiographic worsening of knee OA.

METHODS

In Osteoarthritis Initiative participants with or at higher risk for knee OA enrolled in an accelerometer substudy at 48 months (study baseline), physical activity was measured by a uniaxial accelerometer (ActiGraph GT1M). Radiographic progression was defined as any 48 month to 96 month worsening of Kellgren/Lawrence (K/L) grade scores. All analyses were knee-level; we used multivariable logistic regression with generalized estimating equations, adjusting for key covariates.

RESULTS

Of the 1,206 participants, 631 (52%) were female, the mean ± SD age was 64 ± 9 years, and mean ± SD body mass index (BMI) was 28 ± 5. The mean ± SD average daily sedentary activity was 602 ± 86 minutes, average daily light activity was 284 ± 75 minutes, and average daily moderate-vigorous activity was 20 ± 20 minutes. In 1,978 knees, 267 (14%) had worsening of K/L grade scores. In the multivariable model, age, sex, BMI, and pain, were associated with K/L grade worsening, but neither sedentary activity (adjusted odds ratio [OR] 0.99 [95% confidence interval (95% CI) 0.97-1.01]) nor moderate-vigorous activity (adjusted OR 1.00 [95% CI 0.91-1.09]) were associated with K/L grade worsening.

CONCLUSION

In persons with or at higher risk for knee OA, age, sex, BMI, and pain, but not objectively measured average daily minutes of sedentary or moderate-vigorous activity, were associated with subsequent worsening of K/L grade. Whether findings differ in persons with more severe knee OA and/or engaged more frequently in moderate-vigorous activity should be examined in future studies.

Association between metabolic syndrome and knee structural change on MRI

Objective

To examine the association of metabolic syndrome (MetS) and its components with knee cartilage volume loss and bone marrow lesion (BML) change.

Methods

Longitudinal data on 435 participants from a population-based cohort study were analysed. Blood pressure, glucose, triglycerides and high-density lipoprotein (HDL) were collected. MetS was defined based on the National Cholesterol Education Program–Adult Treatment Panel III criteria. MRI of the right knee was performed to measure cartilage volume and BML. Radiographic knee OA was assessed by X-ray and graded using the Altman atlas for osteophytes and joint space narrowing.

Results

Thirty-two percent of participants had MetS and 60% had radiographic knee OA. In multivariable analysis, the following were independently associated with medial tibial cartilage volume loss: MetS, β = −0.30%; central obesity, β = −0.26%; and low HDL, β = −0.25% per annum. MetS, hypertriglyceridaemia and low HDL were also associated with higher risk of BML size increase in the medial compartment (MetS: relative risk 1.72, 95% CI 1.22, 2.43; hypertriglyceridaemia: relative risk 1.43, 95% CI 1.01, 2.02; low HDL: relative risk 1.67, 95% CI 1.18, 2.36). After further adjustment for central obesity or BMI, MetS and low HDL remained statistically significant for medial tibial cartilage volume loss and BML size increase. The number of components of MetS correlated with greater cartilage volume loss and BML size increase (both P for trend <0.05). There were no statistically significant associations in the lateral compartment.

Conclusion

MetS and low HDL are associated with medial compartment cartilage volume loss and BML size increase, suggesting that targeting these factors has the potential to prevent or slow knee structural change.

Ambulatory activity interacts with common risk factors for osteoarthritis to modify increases in MRI-detected osteophytes

OBJECTIVE

To investigate the longitudinal association between objectively measured ambulatory activity (AA) and knee MRI-detected osteophytes (OPs), and to test whether this relationship was modified by common risk factors for OA including sex, obesity, disease severity and knee injury history.

METHODS

408 community-dwelling adults aged 51-81 years were assessed at baseline and 2.7 years. T1-weighted fat-suppressed MRI was used to evaluate knee OPs at both time points. AA was assessed at baseline by pedometers and categorized as: less active (≤7499 steps per day), moderately active (7500-9999 steps per day) and highly active (≥10,000 steps per day).

RESULTS

Statistically significant interactions were detected between knee OA risk factors and AA on increases in MRI-detected OPs (all P < 0.05). In stratified analyses, being moderately active, compared to being less active, was protective against an increase in MRI-detected OPs (score change of ≥1) in females (relative risk (RR) = 0.42, 95%CI, 0.25-0.70, P < 0.01), those who were obese (RR = 0.50, 95%CI, 0.30-0.83, P < 0.01), those with radiographic OA (ROA) (RR = 0.68, 95%CI, 0.47-0.97, P = 0.02) and those with a history of knee injury (RR = 0.27, 95%CI, 0.08-0.88, P = 0.02) in almost every knee compartment, after adjustment for confounders. No statistically significant associations were found in males, non-obese, non-ROA or non-injury groups.

CONCLUSIONS

Being moderately active is protective against an increase in MRI-detected OPs in females, those with ROA, those who are obese and those with a history of knee injury. These findings suggest that being moderately active is beneficial for individuals who are at higher risk of knee OA.

Predictors of pain severity trajectory in older adults: a 10.7-year follow-up study

OBJECTIVES

To identify distinct pain trajectories over 10.7 years and to examine predictors of identified pain trajectories in an older population and those with radiographic knee osteoarthritis (ROA).

METHODS

963 participants (aged 50-80 years) from a population-based cohort had baseline demographic, psychological, lifestyle and comorbidities data collected. T1-and T2-weighted magnetic resonance imaging (MRI) of the right knee was performed to measure knee structural pathology-cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis. Group-based trajectory modelling (GBTM) was applied to identify trajectories of knee pain over 10.7 years measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

Three distinct pain trajectories were defined: 'Minimal pain' (n = 501, 52%), 'Mild pain' (n = 329, 34%) and 'Moderate pain' (n = 165, 14%). In multivariable analysis, having cartilage defects, BMLs and effusion-synovitis were associated with an increased risk of being in the 'Mild pain' (relative risk [RR]: 1.40 to 1.92) and 'Moderate pain' trajectory (RR: 1.72 to 2.26), compared with the 'Minimal pain' trajectory. Being obese and having more painful sites were associated with 'Mild pain' and 'Moderate pain' trajectories, while unemployment, lower education level and presence of emotional problems were associated with 'Moderate pain' trajectory group. Similar results were found for those with ROA.

CONCLUSION

Distinct pain trajectories identified suggest that homogeneous subgroups exist, which might be useful for phenotypic assessment for pain management, particularly in knee osteoarthritis. Structural pathology was associated with worse pain trajectories, suggesting that peripheral stimuli are critical for the development and maintenance of pain severity. Environmental and psychological factors may exacerbate pain perception.

Objectively Measured Physical Activity and Risk of Knee Osteoarthritis

PURPOSE

This study aimed to examine the association between objectively measured physical activity and risk of developing incident knee osteoarthritis (OA) in a community-based cohort of middle-age and older adults.

METHODS

We used data from the Osteoarthritis Initiative, an ongoing prospective cohort study of adults 45 to 83 yr of age at initial enrollment with elevated risk of symptomatic knee OA. Moderate-vigorous physical activity (MVPA) was measured by a uniaxial accelerometer for seven continuous days in two data collection cycles and was categorized as inactive (<10 min·wk), low activity (10-<150 min·wk), and active (≥150 min·wk). Incident knee OA based on radiographic and symptomatic OA and joint space narrowing were analyzed as outcomes over 4 yr of follow-up. Participants free of the outcome of interest in both knees at study baseline were included (sample sizes ranged from 694 to 1331 for different outcomes). We estimated hazard ratio (HR) with 95% confidence intervals (CI).

RESULTS

In multivariate analyses, active MVPA participation was not significantly associated with risk of incident radiographic knee OA (HR = 1.52, 95% CI = 0.68-3.40), symptomatic knee OA (HR = 1.17, 95% CI = 0.44-3.09), or joint space narrowing (HR = 0.87, 95% CI = 0.37-2.06) when compared with inactive MVPA participation. Similar results were found for participants with low activity MVPA.

CONCLUSION

MVPA was not associated with the risk of developing incident knee OA or joint space narrowing over 4 yr of follow-up among Osteoarthritis Initiative participants who are at increased risk of knee OA.

Effects of long-term exercise therapy on knee joint structure in people with knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVE

To investigate effects of long-term exercise therapy for people with knee osteoarthritis (OA) on radiographic disease severity and cartilage integrity (primary outcomes) as well as severity of bone marrow lesions (BMLs), synovitis and/or effusion (secondary outcomes).

METHODS

We sourced randomized controlled trials in people with clinical and/or radiographic OA investigating the effect of land-based exercise therapy of > 6 months on radiographic disease severity and magnetic resonance imaging outcomes of cartilage integrity (morphology or composition) as well as BML, synovitis and/or effusion severity, when compared to no exercise. Two independent reviewers extracted data and assessed risk of bias. Random-effects meta-analysis was used to pool standardised mean differences (SMD) (95% confidence intervals (CI)) or odds ratios (OR) (95% CI) and estimate heterogeneity (I², %). Quality of the pooled body of evidence was rated implementing the GRADE approach. Studies unsuitable for meta-analysis were summarized in a best-evidence synthesis.

RESULTS

Meta-analysis showed moderate quality evidence of no treatment effect on tibiofemoral radiographic disease severity ((SMD) 95% (CI): 0.06 (-0.07, 0.20), I²= 0%) and low-quality evidence of no effect on tibiofemoral cartilage morphology (SMD (95%): 0.06 (-0.20, 0.36), I²= 0%). Low quality evidence revealed no treatment effect on the odds of change in synovitis ((OR) (95% CI): 0.90 (0.51,1.60), I²= 0%) and effusion ((OR (95% CI): 0.88 (0.64, 1.20), I²= 0%), but greater odds of tibiofemoral BMLs worsening (OR (95% CI): 1.90 (1.11, 3.26), I²= 0%). In best-evidence synthesis, limited evidence was found for changes in patellar cartilage composition following exercise in women with mild knee OA compared to no exercise, but not for tibiofemoral cartilage.

CONCLUSION

Long-term exercise therapy did not change tibiofemoral radiographic disease severity, cartilage morphology or synovitis/effusion, but may slightly increase the likelihood for increased BML severity. Overall, meta-analysis findings were limited in directness and precision and restricted to relatively imprecise effect estimates in people who were obese on average. Limited evidence suggested some protective effects on patellar cartilage composition.

Duration of physical activity, sitting, sleep and the risk of total knee replacement among Chinese in Singapore, the Singapore Chinese Health Study

Objectives

While the effect of physical activity on knee osteoarthritis (KOA) remains controversial, how sitting and sleep durations affect KOA is unknown. We evaluated the association between durations of physical activity, sitting and sleep, and incidence of total knee replacement (TKR) due to severe KOA.

Methods

We used data from the Singapore Chinese Health Study, a prospective cohort of 63,257 Chinese, aged 45–74 years at recruitment from 1993–1998. Height, weight, lifestyle factors, hours of sitting and sleep per day, and hours of moderate activity, strenuous sports or vigorous work per week were assessed through in-person interviews using structured questionnaires. Incident cases of TKR were identified via record linkage with nationwide hospital discharge database.

Results

Compared to those with <0.5 hour/week of moderate physical activity, participants with ≥5 hour/week had increased risk of TKR risk [hazard ratio (HR) 1.16, 95% confidence interval (CI) 1.00–1.35]. Conversely, duration of sitting activities, especially sitting at work, was associated with reduced risk in a stepwise manner. Compared to <4 hour/day of sitting, those with ≥12 hour/day had the lowest risk (HR 0.76, 95% CI 0.60–0.96, p for trend = 0.02). Sleep duration was inversely associated with reduced risk of TKR in a dose-dependent manner; compared to those with sleep ≤ 5 hour/day, participants with ≥ 9 hour/day had the lowest risk (HR 0.55, 95% CI) 0.43–0.70, p for trend <0.001).

Conclusion

While prolonged sitting or sleeping duration could be associated with reduced risk of severe KOA, extended duration of physical activity could be associated with increased risk.

A protocol for a multicentre, randomised, double-blind, placebo-controlled trial to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change and knee pain over 24 months in knee osteoarthritis patients - ZAP2

BACKGROUND

Bisphosphonates are a class of drugs that slow bone loss and are a promising candidate to treat knee osteoarthritis (OA) patients. In a pilot study, we demonstrated that zoledronic acid reduced knee pain and size of subchondral bone marrow lesions (BMLs) over 6 months in knee OA patients with significant knee pain and BMLs. A longer, larger study is required to assess whether decreases in BML size will translate to reductions in cartilage loss over time. We are currently conducting a multicentre, randomised, double-blind, placebo-controlled trial over 24 months that aims to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change (assessed using magnetic resonance imaging (MRI)) and knee pain in knee OA patients.

METHODS

Two hundred sixty-four patients with clinical knee OA, significant knee pain and subchondral BMLs present on MRI will be recruited in Hobart, Melbourne, Sydney and Adelaide. They will be randomly allocated to the two arms of the study, receiving an annual identical intravenous infusion of either 100 mL of fluid containing zoledronic acid (5 mg/100 mL) or placebo (0.9% NaCl 100 mL), at baseline and 1 year later. MRI of the study knee will be performed at screening, month 6 and 24. Knee structure, symptoms and function will be assessed using validated methods. The primary outcome is absolute change in tibiofemoral cartilage volume (mm3) over 24 months. Secondary outcomes include improvement in knee pain over 3, 6, 12, 18, and 24 months and reductions in BML size over 6 and 24 months. The primary analyses will be intention-to-treat analyses of primary and secondary outcomes. Per protocol analyses will be performed as the secondary analyses.

DISCUSSION

This study will provide high-quality evidence to assess whether zoledronic acid has a novel disease modifying effect in OA by slowing cartilage loss and reducing pain. If zoledronic acid proves effective, it suggests great potential for cost savings through a delay or reduced need for joint replacement surgery, and potential for great improvements in quality of life for OA suffers.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12613000039785 , registered on 14 January 2013.

Prevalence of knee osteoarthritis features on magnetic resonance imaging in asymptomatic uninjured adults: a systematic review and meta-analysis

Background

Knee MRI is increasingly used to inform clinical management. Features associated with osteoarthritis are often present in asymptomatic uninjured knees; however, the estimated prevalence varies substantially between studies. We performed a systematic review with meta-analysis to provide summary estimates of the prevalence of MRI features of osteoarthritis in asymptomatic uninjured knees.

Methods

We searched six electronic databases for studies reporting MRI osteoarthritis feature prevalence (ie, cartilage defects, meniscal tears, bone marrow lesions and osteophytes) in asymptomatic uninjured knees. Summary estimates were calculated using random-effects meta-analysis (and stratified by mean age: <40 vs ≥40 years). Meta-regression explored heterogeneity.

Results

We included 63 studies (5397 knees of 4751 adults). The overall pooled prevalence of cartilage defects was 24% (95% CI 15% to 34%) and meniscal tears was 10% (7% to 13%), with significantly higher prevalence with age: cartilage defect <40 years 11% (6%to 17%) and ≥40 years 43% (29% to 57%); meniscal tear <40 years 4% (2% to 7%) and ≥40 years 19% (13% to 26%). The overall pooled estimate of bone marrow lesions and osteophytes was 18% (12% to 24%) and 25% (14% to 38%), respectively, with prevalence of osteophytes (but not bone marrow lesions) increasing with age. Significant associations were found between prevalence estimates and MRI sequences used, physical activity, radiographic osteoarthritis and risk of bias.

Conclusions

Summary estimates of MRI osteoarthritis feature prevalence among asymptomatic uninjured knees were 4%–14% in adults aged <40 years to 19%–43% in adults ≥40 years. These imaging findings should be interpreted in the context of clinical presentations and considered in clinical decision-making.

Physical activity is associated with changes in knee cartilage microstructure

OBJECTIVE

The purpose of this study was to determine if there is an association between objectively measured physical activity and longitudinal changes in knee cartilage microstructure.

METHODS

We used accelerometry and T₂-weighted magnetic resonance imaging (MRI) data from the Osteoarthritis Initiative, restricting the analysis to men aged 45-60 years, with a body mass index (BMI) of 25-27 kg/m² and no radiographic evidence of knee osteoarthritis. After computing 4-year changes in mean T₂ relaxation time for six femoral cartilage regions and mean daily times spent in the sedentary, light, moderate, and vigorous activity ranges, we performed canonical correlation analysis (CCA) to find a linear combination of times spent in different activity intensity ranges (Activity Index) that was maximally correlated with a linear combination of regional changes in cartilage microstructure (Cartilage Microstructure Index). We used leave-one-out pre-validation to test the robustness of the model on new data.

RESULTS

Nineteen subjects satisfied the inclusion criteria. CCA identified an Activity Index and a Cartilage Microstructure Index that were significantly correlated (r = .82, P < .0001 on test data). Higher levels of sedentary time and vigorous activity were associated with greater medial-lateral differences in longitudinal T₂ changes, whereas light activity was associated with smaller differences.

CONCLUSIONS

Physical activity is better associated with an index that contrasts microstructural changes in different cartilage regions than it is with univariate or cumulative changes, likely because this index separates the effect of activity, which is greater in the medial loadbearing region, from that of patient-specific natural aging.