Effects of Exercise Therapy on Molecular Biomarkers in Knee Osteoarthritis

Exercise therapy is not harmful in patients with knee osteoarthritis (OA) and does not increase the concentration of molecular biomarkers associated with cartilage turnover and inflammation that are implicated in the progression of OA, according to the results of a systemic review and meta-analysis published in Arthritis Care & Research.

The investigators sought to explore the effect of exercise therapy on molecular biomarkers associated with cartilage and inflammation in individuals at risk for or with established knee OA. They performed a literature search through September 2017 and included a total of 12 randomized controlled trials. The trials involved 57 study comparisons at 4 to 24 weeks following an exercise therapy intervention.

Exercise therapy decreased molecular biomarkers in 30% of study comparisons, had no effect in 63% of study comparisons, and increased molecular biomarkers in 7% of study comparisons. Based on meta-analyses of 9 biomarkers, exercise therapy was associated with nonsignificant reductions in C-reactive protein, C-terminal crosslinking telopeptide of type II collagen, tumor necrosis factor alpha (TNF-α), soluble TNF-α receptor-1 and receptor-2, C2C neoepitope of type II collagen, and cartilage oligomeric matrix protein compared with non-exercising control groups. Moreover, exercise therapy had no effect on interleukin-6 (IL-6) and soluble IL-6 receptor.

The investigators concluded that exercise therapy is not harmful in individuals with knee OA as it does not increase the concentration of molecular biomarkers linked to cartilage turnover and inflammation, which are potentially involved in the progression of OA.  In this review, the overall quality of evidence supporting the conclusion was downgraded to low, however, because of the limited number of trials that were available for analysis. Future studies are warranted that obtain synovial fluid from persons at risk for OA and focus on a set of biomarkers rather than on individual biomarkers.

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Reference

Bricca A, Struglics A, Larsson S, Steultjens M, Juhl CB, Roos EM. Impact of exercise therapy on molecular biomarkers related to cartilage and inflammation in people at risk of, or with established, knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials [published online October 15, 2018].  Arthritis Care Res (Hoboken). doi:10.1002/acr.23786