3D CT analysis of femoral and tibial tunnel positions after modified transtibial single bundle ACL reconstruction with varus and internal rotation of the tibia

IntroductionWe analyzed the location of femoral and tibial tunnels by three-dimensional (3D) CT reconstruction images after modified transtibial single bundle (SB) anterior cruciate ligament (ACL) reconstruction, creating a femoral tunnel with varus and internal rotation of the tibia.Material and methodsData from 50 patients (50 knees) analyzed by 3D CT after modified transtibial SB ACL reconstructions were evaluated. 3D CT images were analyzed according to the quadrant method by Bernard at the femur and the technique of Forsythe at the tibia.ResultsThe mean distance of the femoral tunnel center locations parallel to the Blumensaat's line was 29.6% ± 1.9% along line t measured from the posterior condylar surface. The mean distances perpendicular to the Blumensaat's line were 37.9% ± 2.5% along line h measured from the Blumensaat's line. At the tibia, the mean anterior-to-posterior distance for the tunnel center location was 37.8% ± 1.2% and the mean medial-to-lateral distance was 50.4% ± 0.9%.DiscussionThe femoral and tibial tunnels after modified transtibial SB ACL reconstruction creating a femoral tunnel with varus and internal rotation of the tibia (figure-of-4 position) were located between the anatomical anteromedial and posterolateral footprints.