Impact of exercise on the functional capacity and pain of patients with knee osteoarthritis: a randomized clinical trial

Background: Muscle weakness, especially of the quadriceps muscle, is one of the major musculoskeletal effects of knee osteoarthritis. Exercises are considered one of the main interventions in the conservative treatment of those patients. Objective: To assess the effectiveness of quadriceps strengthening exercises on functional capacity and symptoms related of knee osteoarthritis by use of the Timed Up and Go test (TUG), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Lequesne Index. Methods: One hundred patients were randomized into two groups: 1) Exercise Group (n = 50), which included stationary bicycle, hamstrings stretching, and quadriceps strengthening; 2) Instruction Group (n = 50), which received a manual with information about knee osteoarthritis and instructions on how to deal with knee symptoms in daily activities. The manual did not include exercise instructions. Results: The Exercise Group showed statistically significant improvement regarding the TUG test, the WOMAC aspects of pain, function, and stiffness, and the Lequesne Index, as compared with the Instruction Group. Conclusion: Quadriceps strengthening exercises for eight weeks are effective to improve pain, function, and stiffness in patients with knee osteoarthritis.