Study Finds Exercise Doesn't Harm Knees With Osteoarthritis
Contrary to the belief of some, exercise does not harm knee joints of those with, or at risk for, osteoarthritis.
According to a meta-analysis of randomized controlled trials, it's been concluded that if anything, exercise actually is beneficial for cartilage. Alessio Bricca from the University of Southern Denmark, and her colleagues, say their analysis indicated that molecular biomarkers associated with inflammation and cartilage breakdown, were reduced with exercise.
The analysis included 12 studies that looked at the influence of strengthening or aerobic exercise in 1,114 participants. All of the studies took biomarker samples at 1 to 6 months, and looked at molecular biomarkers relating to inflammation, grouped into markers of inflammation and cytokine receptors, and biomarkers relating to cartilage turnover, grouped into proteases, collagen turnover, glycoproteins, and glycosaminoglycans.
Together the studies performed 57 comparisons, of which 63% found that biomarker concentrations were similar between the exercise and control groups, while 30% reported a decrease in concentrations with exercise and 7% reported an increase - all in favor of exercise therapy.
Previous meta-analyses have similarly found that exercise is not associated with excessive risk for people with knee osteoarthritis. Previous magnetic resonance imaging trials have also shown that exercise does not harm cartilage.
They add that the findings of the current study are “in line with these previous findings and support exercise therapy being a safe treatment for knee joint cartilage in people at risk of, or with established, knee osteoarthritis.”
"Molecular biomarkers obtained from the synovial fluid appeared to be more sensitive to changes with exercise therapy than samples from urine or blood because of the proximity of the synovial fluid to the joint tissues", says Bricca, and she recommends that future studies should use synovial fluid for assessment. Also, as no single biomarker has yet been shown to explain the development and progression of osteoarthritis, Bricca and colleagues suggest that future studies focus on a set of biomarkers, rather than a single marker.
Limitations of the analysis included a lack of studies reporting findings for the same biomarkers and wide confidence intervals. However, the researchers have still concluded that "people at risk of, or with established, knee osteoarthritis can be told that exercise therapy is not harmful, and if anything, is positive for the turnover of articular cartilage and inflammation.”