Adults at high risk of knee arthritis may engage in vigorous activities

Engaging in long-term strenuous physical activities* was not associated with radiographic knee osteoarthritis (OA) in individuals at an increased risk for but without radiographic evidence of the disease, a new study has shown.

“Our findings convey a reassuring message that adults at high risk for knee OA may safely engage in long-term strenuous physical activity at a moderate level to improve their general health and well-being,” said Associate Professor Alison Chang from the Northwestern University Feinberg School of Medicine in Chicago, Illinois, US, in a press release.

The adjusted odds ratios between 10-year incident radiographic knee OA and low-to-moderate or any level of strenuous physical activity ranged from 0.69–0.75. Although not statistically significant, these imply that vigorously exercising adults even for 1–2 hours/week were 30 percent less likely to develop knee OA, explained the researchers. [JAMA Network Open 2020;3:e204049]

It pays to be early

Exercise and physical activity are recommended for first-line knee OA management. [Ann Rheum Dis 2013;72:1125-1135 Osteoarthritis Cartilage 2014;22:363-388] However, in adults with knee symptoms, the uncertainty about further joint damage with vigorous activity outweighs its known health benefits. [J Appl Gerontol 2017;36:1091-1116; Arthritis Care Res 2012;64:1554-1564]

“[Therefore, they] often avoid or curtail vigorous physical activity for fear of further harm,” they said. Should they decide to manage the symptoms, it could happen at a point when structural damage and chronic pain sensitization have set in, hence the limited efficacy of the treatment approach used. [Arthritis Rheumatol 2014;66:1811-1819; Ann Rheum Dis 2015;74:682-688]

To avoid this conundrum, proactive intervention at an early stage is key to achieve optimal therapeutic outcomes. The team thus sought to evaluate 1,194 adults (58 percent female, mean age 58 years) from the Osteoarthritis Initiative who were at high risk for knee OA.

“[Individuals] at high risk but without evidence of radiographic knee OA are at a stage when joint symptoms are frequently minimal or mild and tissue damage is not yet widespread. Physical activity programmes instituted [before the onset of joint damage and chronic pain] are more likely to be effective and achievable,” said the researchers.

Join the movement

Despite the large and comprehensively assessed cohort followed for an extended period, self-reported measures could have introduced bias, noted the researchers. Nonetheless, they pointed out that opting for accelerometry and processing recordings by the minute to quantify activity or the lack thereof for a long period in a large group would be very taxing, costly, and time-consuming.

Overall, the findings may inform public health messages and steer customized physical activity promotion and sedentary behaviour reduction strategies and interventions, the researchers said. “Healthcare providers may consider incorporating physical activity counselling as part of standard care for high-risk individuals at an early stage when physical activity engagement is more attainable … Promoting physical activity and reducing sedentary behaviour are low-cost, easy-to-implement strategies to improve health and quality of life.”

Studies with longer follow up periods with more incident cases may ascertain the link between physical activity patterns over time and disease progression, they added.