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Thresholds in Strength Function in Knee OA

Arthritis Care Res; ePub 2018 Aug 29; Bacon, et al

In persons with symptomatic knee osteoarthritis (OA), thresholds in the strength function relationship may help identify individuals, especially women, at the brink of disability insofar as strength and daily tasks. This according to a recent study that investigated the thresholds of strength below which people with knee OA may have more difficulty carrying out physical functions of daily life. Researchers studied persons with symptomatic OA at baseline in the Multicenter Osteoarthritis Study (MOST) who had knee extensor strength measured isokinetically at 60°/sec. 834 participants (65.8% women) were on average 62.9 (±7.9) years old. Subjects underwent a 20‐meter walk test, a Sit‐to‐Stand Test, and answered the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Physical function results were plotted against measures of quadriceps strength (newton‐meters, Nm) (and as strength/body weight) for the worse knee. They found:

  • In women, there were thresholds of strength below which the slope of strength vs function was steeper: walking speed (<58Nm), chair stand time (<32Nm), and WOMAC functions rising from a chair and getting on/off the toilet (<38Nm).
  • No thresholds were found in men.

Citation:

Bacon KL, Segal NA, Øiestad BE, et al. Thresholds in the relationship of quadriceps strength with functional limitations in women with knee osteoarthritis. [Published online ahead of print August 29, 2018]. Arthritis Care Res. doi:10.1002/acr.23740.