Placement of femoral tunnel between the AM and PL bundles using a transtibial technique in single-bundle ACL reconstruction

Two different approaches for drilling the femoral tunnel are commonly used in single-bundle anterior cruciate ligament (ACL) reconstruction: creating the femoral tunnel through the tibial tunnel or drilling the tunnel through a low anteromedial arthroscopy portal. When using a transtibial drilling technique, the location of the femoral tunnel is restricted by the angulation of the tibial tunnel in the coronal plane and may lead to a high placement of the femoral tunnel in the intercondylar notch. However, some authors refer that the femoral tunnel can be positioned correctly in the center of the femoral ACL footprint by means of a transtibial technique if the tibial tunnel forms an angle between 60° and 65° to the medial joint line of the tibia in the coronal plane. The purpose of this study was to evaluate prospectively with CT scans whether a femoral tunnel drilled through a tibial tunnel at an angle of 60°-65° in the coronal plane is created between the AM and PL bundles in the lateral femoral condyle. Our results showed that the median difference of the distance between the center of the femoral tunnel and the center of the AM and PL bundles along the Blumensaat's line was 6 and 5%, respectively. In the height of the femoral condyle, the median difference of the distance between the center of the femoral tunnel and the center of the AM and PL bundles was 0 and 31%, respectively. In conclusion, when drilling the femoral tunnel via a transtibial technique with the tibial tunnel angled 60°-65° in the coronal plane, the center of the femoral tunnel is created in the AM bundle footprint in the height of the femoral condyle.