BIOMECHANICAL MECHANISMS UNDERLYING TREATMENT EFFECTS OF EXERCISE THERAPY IN PATIENTS WITH KNEE OSTEOARTHRITIS: DATA FROM A RANDOMIZED CONTROLLED TRIAL.

Background: Underlying mechanisms of exercise-induced effects in knee osteoarthritis (OA) are unclear. Objectives: To evaluate longitudinal associations between changes in biomechanical functions and changes in pain and activity limitations in knee OA patients treated with exercise therapy. Methods: Data were used from a randomized controlled trial (NTR1475) in which two exercise programs of 12 weeks were compared. One hundred forty nine patients with knee OA, who completed a 12-week exercise program, were measured at baseline and at 6-, 12- and 38-week follow-up. Generalized Estimating Equations (GEE) analyses were used to determine longitudinal associations of changes in biomechanical functions (upper leg muscle strength, knee joint proprioception, self-reported knee instability and knee flexion and extension range of motion) with changes in pain severity (numeric rating scale) and activity limitations (WOMAC, physical function and Get up and go test) over time (i.e. baseline, 6-, 12- and 38-week follow-up). Univariable and multivariable associations, analyzing all biomechanical functions together, were performed. Results: Improvements in upper leg muscle strength (both quadriceps and hamstrings strength) and self-reported knee stability were longitudinally associated with outcome of exercise therapy, i.e. improvements in pain and activity limitations, while improvements in proprioceptive accuracy or knee range of motion were not (see Table 1). Conclusions: Muscle strengthening and knee stabilization were consistently associated with outcome of exercise therapy in knee OA patients. These findings provide better insight in underlying biomechanical mechanisms of exercising in OA, contributing to optimal effectiveness of exercise therapy. Disclosure of Interest: None DeclaredCitation: , volume 72, supplement s3, year 2013, page Session: Poster session Friday ( )