Exercise Therapy in Patients With Knee Osteoarthritis

Osteoarthritis (OA) is one of the most common form of chronic diseases in the adult population, and approximately 800 000 people in Sweden (population of 9 million people) suffer from this disease, which causes joint pain, stiffness, swelling, loss of function and sick leave. There is increasing evidence that exercise therapy is effective for patients with knee OA. However, there is little knowledge on long-term effects and what type of exercises dosage is most effective. In this present clinical trial, which is a Nordic collaborative project with researchers from different research groups in Sweden and Norway, we intend to investigate short and long-term effects comparing high dosage exercise therapy (each treatment lasting 80 to 90 min) vs. a relatively low dosage exercise program (25 to 30 min) in patients diagnosed with knee OA. Patients in both intervention groups receive three treatments a week for 12 weeks making a total of 36 treatments. Primary outcome is pain-ratings and function (The Knee Injury and Osteoarthritis Outcome Score (KOOS)). Secondary outcome concerns various health-ratings and objective functional tests. Regarding predictors for outcome, we plan also to investigate different psychosocial variables as well as patient\'s beliefs regarding exercise. Feasibility of how high-dose exercise therapy actually works in primary care health care settings is also planned to be reported. Patients are being assessed by blinded assessor at inclusion, at end of intervention (3 mo), and at six and 12 mo after end of treatment. We plan to include a total of 200 subjects from primary health care settings, two in Norway and two in Sweden, with radiographic-verified knee OA with knee pain and decreased function. The patients have to be within the 45 to 85 age group. Patients are excluded if they have been scheduled for knee surgery or have some other form of illness/disease that limits the exercise tolerance (e.g. heart disease or systemic/metabolic diseases or chronic obstructive airways disease). A major goal is to grade exercises so that they are performed pain-free or close to pain-free in both intervention groups. The principle of deloading is used to meet this goal using a high number of repetitions in sets as pain modulation. The results from this study will give new information about the effectiveness of graded exercise therapy in patients with knee OA, and new knowledge if outcome can be related to the exercise dosage performed.