Effect sizes of KOOS, WOMAC and SF-36 six months after ACL-reconstruction. Comparison of effect sizes of KOOS, WOMAC and SF-36 six months after surgical reconstruction of the ruptured anterior cruciate ligament. Effect size was defined as mean score change divided by the pre-operative standard deviation. The data are previously published (n = 21, mean age 32 years) . Placebo or sham treatment results have not been subtracted to generate effect sizes. It should be noted that the effect size displayed here will be influenced by the preoperative within-group variation of the score dimension measured.