Moderate Physical Activity Slows Cartilage Loss in Women With Knee Osteoarthritis

Moderate physical activity may prevent cartilage loss and slow the progression of knee osteoarthritis (OA) in women, according to a study recently published in Arthritis Care & Research.

The study included 689 participants with baseline radiographic knee OA with Kellgren/Lawrence grade >2 based on central readings, physical activity documented at baseline and annually for 4 years based on the Physical Activity Scale for the Elderly (PASE) questionnaire, and available MRI-based cartilage thickness assessment at baseline and at the 4-year assessment. The MRI-based cartilage thickness change in the medial femorotibial compartment (MFTC) over 4 years was the primary outcome measurement.

Mean cartilage thickness change in the MFTC was -0.20 mm (95% CI, -0.22 to 0.17 mm) for the entire cohort. After adjustment for baseline characteristics, there was no statistically significant difference in cartilage thickness change in the MFTC between PASE tertiles (low, moderate, high).

However, investigators observed a sex-by-physical activity interaction with adjusted analysis (P =.02). Women with low physical activity level had a statistically greater loss of cartilage compared with women with moderate physical activity level (adjusted between-group difference -0.09 mm; 95% CI, -0.16 to 0.02 mm). No statistically significant difference in cartilage loss between physical activity levels was noted in men. Investigators also found that high physical activity level was not more harmful than low or moderate physical activity level for structural changes in both men and women. 

The results of this study suggest that women with knee OA should engage in moderate physical activity to slow loss of cartilage and disease progression. Additionally, clinicians should assure knee OA patients that high physical activity is not more harmful than low or moderate physical activity. 

The authors note some funding came from Merck Research Laboratories, Novartis Pharmaceuticals Corporation, GlaxoSmithKline, and Pfizer, Inc. Please see the source for a full list of disclosures.

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Reference

Bricca A, Wirth W, Juhl CB et al. Moderate physical activity may prevent cartilage loss in women with knee osteoarthritis: data from the Osteoarthritis Initiative [published online October 19, 2018]. Arthritis Care Res. doi: 10.1002/acr.23791.