STATISTICAL METHOD All subjects assigned to treatment will be included in the efficacy analyses (i.e. intention to treat analysis). Between-group comparisons of the primary end point will be made with the use of a random effects model. 10/100 points for the KOOS questionnaire subscales are chosen as a clinical important or relevant difference, thus a confidence interval excluding differences greater than 10 units between groups is interpreted as indicating the absence of a clinically meaningful difference.