Each treatment in the high dosage group (also called "Medical Exercise Therapy, MET) consist of 20 minutes global exercise (e.g. stationary cycling), then four local knee exercises either open or closed chain performing three sets of 30 repetitions or five minutes continuous repetitions, then another five minutes cycling followed by another four local knee exercises three sets of 30 repetitions or five minutes continuous repetitions and finishing with 10 minutes cycling. Each treatment lasts 80 to 90 minutes. The patients in this group shall also perform one home exercise every day performing three sets of five minutes deloaded knee extension with therabands. In the low dosage exercise group the patients perform a total of five exercises; 10 minutes warm up using a stationary bicycle, then four different knee exercises performing two sets of 10 repetitions. Each treatment last 20 to 30 minutes.