The long-term efficacy of strength or aerobic exercise on quality of life and knee function in patients with knee osteoarthritis. A multi-arm randomized controlled trial

Objective: To evaluate the efficacy of strength exercise or aerobic exercise compared to usual care on knee-related quality of life (QoL) and knee function after 4 months and 1 year in individuals with knee osteoarthritis. Methods A three-arm randomized controlled trial (RCT) compared 12-weeks of strength exercise or aerobic exercise (stationary cycling) to usual care supervised by physiotherapists in primary care. We recruited 168 participants aged 35–70 years with symptomatic knee osteoarthritis. Primary outcome was The Knee Injury and Osteoarthritis Outcome Score (KOOS) QoL after 1 year. Secondary outcomes were self-reported function, pain, and self-efficacy, muscle strength and voluntary maximal oxygen consumption (VO 2peak ) at 4 months and 1 year. Results There were no differences between strength exercise and usual care on KOOS QoL (6.5, 95% CI -0.9 to 14), or for aerobic exercise and usual care (5.0, 95% CI -2.7 to 12.8), at 1 year. The two exercise groups showed better quadriceps muscle strength, and VO 2peak at 4-months, compared to usual care. Conclusion This trial found no statistically significant effects of two exercise programs compared to usual care on KOOS QoL after 1 year in individuals with symptomatic and radiographic knee osteoarthritis, but an underpowered sample size may explain lack of efficacy between the intervention groups and the usual care group.