Does exercise-therapy increase physical activity in people with knee osteoarthritis? A systematic review

Abstract

Introduction: Physical activity has important general, physical and mental health benefits. Few (13%) people with knee osteoarthritis meet physical activity guidelines; and over half (60%) have one or more other chronic comorbidities. This review aims to investigate the effects of exercise-therapy on physical activity levels in people with knee osteoarthritis. Secondary aims included investigating the effects of exercise-therapy on (i)-physical fitness; and (ii)-measures of general health. Methods: This systematic review of randomised-controlled trials with meta-analysis was registered in PROSPERO (#CRD42020140796). We searched five databases from inception until June 2019. Randomised controlled trials involving exercise-therapy for people with knee osteoarthritis were included. The Cochrane risk-of-bias tool was used by two reviewers to independently appraise articles. We extracted data at three timepoints: short-term (<6 months), medium-term (6-11 months) and long-term (≥12 months). Certainty of meta-analyses was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Results: We screened 5190 studies for eligibility, 66 full-text articles were assessed. Eleven randomised controlled trials (12 articles) were included. Nine trials compared exercise-therapy to no intervention and two compared exercise-therapy to another intervention. Low certainty evidence from six trials indicates a small increase in physical activity for exercise-therapy compared to no intervention at short-term follow-up (standardised mean difference (SMD) [95 % confidence interval (CI)]=0.35[0.03,0.67]). Sensitivity analysis found that walking programs (n=3) had a moderate effect on physical activity (0.69[0.23,1.14]), while resistance programs (n=3) had no effect (0.09[-0.11,0.29]). Very-low certainty evidence from two trials found no effect of exercise-therapy on physical fitness for exercise-therapy compared no intervention at short-term follow-up (SMD[95% CI]=0.40[-0.59,1.38]). Individual trials reported small improvements for systolic blood pressure, waist circumference and body mass when exercise-therapy is compared to no intervention. Discussion: Exercise-therapy for people with knee osteoarthritis can improve pain/function and may also increase physical activity. However, this effect may be specific to exercise-therapy type, with aerobically targeted exercise-therapy (walking programs), but not resistance training, increasing physical activity. Future exercise-therapy trials are encouraged to include physical activity monitoring to increase the certainty of these findings. Exercise-therapy may also improve general health, but findings are currently limited to single trials. Targeted physical activity interventions are required to address the disparity of people with knee osteoarthritis participating in physical activity. Conflict of interest statement: Authors acknowledge that we have no conflicts of interest relevant to the submission of this abstract.