Effects of Blood-flow Restricted Exercise Compared to Standard Rehabilitation in Patients With Knee Osteoarthritis

Inclusion Criteria: * All participants must meet the American College of Rheumatology (ACR) criteria for OA 35. * Visible OA on X-ray pictures (Kellgren \& Lawrence grade 2-3). * Unilateral pain and functional limitation for a minimum of 3 months. * Be able to voluntarily (i.e. unassisted) perform a 90 degrees flexion in the knee. * Be able to perform the machine exercise (knee extension) planned for the BFR training. * Danish-speaking. * No longer travel planned within the intervention period. Exclusion Criteria: * Kellgren \& Lawrence grade 4. * Bilateral OA-symptoms. * Prior knee- or hip alloplasty. * Glucocorticosteroid injection in the knee within the last 6 months. * Inflammatory arthritis. * Known neurotic disease such as multiple sclerosis or peripheral neuropathy. * Prior myocardial infarct or apoplexy, or chest pain during physical activity. * Other health related or medical conditions which makes it impossible participate in the study. Furthermore, it is an exclusion criterium in the following conditions where use of pneumatic occlusion would be considered contraindicated: * Peripheral vascular disease * Excessive varicose veins * Prior history of deep venous thrombosis * Venous insufficiency causing edema in the lower legs * Systolic blood pressure over 160 mmHg or under 100 mmHg