Limited accuracy of transtibial aiming for anatomical femoral tunnel positioning in ACL reconstruction

Abstract

Background: Anterior cruciate ligament (ACL) rupture is a common knee injury, and with advancements in knee arthroscopy, ACL reconstruction has become common. Techniques like single-double bundle and femoral tunnel drilling via transtibial or anteromedial portal approaches are available. This study evaluates the accuracy of femoral tunnel placement via these approaches in single-bundle ACL reconstruction. Materials and methods: Forty-three ACL reconstructions using hamstring grafts were analyzed. Initially, femoral tunnels were drilled via the anteromedial portal from 09:30 to 10:00 (14:00 to 14:30 for left knees). Tibial tunnels (mean anteroposterior angle: 63.5°, sagittal: 64.2°) were then created with the same diameter, accompanied by radiological documentation. A femoral aiming device was used to place a K-wire at the center of the femoral tunnel, recorded photographically. Tunnel diameters included 7 mm (20 cases), 7.5 mm (11 cases), 8 mm (7 cases), 8.5 mm (3 cases), and 9 mm (1 case). Two observers evaluated all radiological and photographic data, focusing on the deviation of the transtibial K-wire from the femoral tunnel center. Results: Of 38 evaluated cases, the transtibial K-wire was within the femoral tunnel in 11 cases (28.9%) – 7 cases with 7 mm, 2 cases each with 7.5 mm and 8 mm diameters. In 23 cases (60.5%), the K-wire was at the perimeter or outside the femoral tunnel – 11 cases with 7 mm, 8 with 7.5 mm, 4 with 8 mm, 3 with 8.5 mm, and 1 with 9 mm diameters. Conclusion: Transtibial aiming for anatomical femoral tunnel positioning is challenging. No significant correlation was found between the transtibial deviation and the tibial tunnel diameter