80 patients were randomized to undergo double-bundle anterior cruciate ligament (ACL) reconstruction using either the transportal (TP) or outside-in (OI) technique in order to compare the accuracy of femoral tunnel length between the methods. Following evaluations over 2 weeks, it was observed that intraoperative femoral tunnel lengths were longer intraoperatively than postoperatively for both groups. However, the OI group had longer anteromedial and posterolateral femoral tunnel lengths intraoperatively, and longer anteromedial femoral tunnel lengths postoperatively. The length of the posterolateral-fixed graft differed between groups significantly.