Effects of exercise on functional aerobic capacity in lower limb osteoarthritis: a systematic review

Osteoarthritis (OA) is a degenerative joint disease. The reduced aerobic capacity of patients with lower limb osteoarthritis affects their independence in performing everyday activities. The purpose of this systematic review was to summarize evidence for the effectiveness and structure of exercise programs on functional aerobic capacity (ability to perform activities of daily living that require sustained aerobic metabolism) in patients with hip and knee osteoarthritis. A computerized search was made of seven databases. Effect sizes (ES) and 95% confidence intervals (CI) were calculated, and the heterogeneity of the studies was assessed using Cochran's Q statistic applied to the ES means. The 20 studies that satisfied the inclusion criteria were selected for analysis. These studies were grouped into five categories according to the characteristics of the exercise program: land-based interventions (strength programs, tai chi, aerobic programs, mixed exercise programs) and aquatic intervention (hydrotherapy). The functional aerobic capacity improved in tai chi programs (ES=0.66; 95% CI, 0.23-1.09), aerobic programs (ES=0.90; 95% CI, 0.70-1.10), and mixed programs (ES=0.47; 95% CI, -0.38-0.39). The conclusions were: (i) despite recommendations for the use of exercise programs for aerobic fitness in patients with hip and knee osteoarthritis, few randomized clinical trials have been conducted; (ii) the structure of the exercise programs (program content and duration, and session frequency and duration) is very heterogeneous; (iii) overall, exercise programs based on tai chi, aerobic, and mixed exercise seem to give better results than hydrotherapy programs, but without the differences being altogether clear.