The position of the center of femoral tunnel was decided in the complete femoral stub. Then the length from the ADC to the anterior cartilage margin（L1）and to the center of femoral tunnel（l1），as well as the center to the distal cartilage margin（D1）were measured under arthroscopy and on post-operative CT scan（L2，l2 and D2）. Moreover，P1 and P2 were calculated through l1/L1 and l2/L2.
To examine the consistency between postoperative CT scan and intraoperative arthroscopic measurement in evaluating femoral tunnel position for anterior cruciate ligament （ACL）reconstruction，both using the apex of the deep cartilage（ADC）as the marker.