Comparison of femoral graft bending angle and tunnel length between transtibial technique and transportal technique in anterior cruciate ligament reconstruction

Purpose: To investigate which technique would reduce bending stress at the femoral tunnel aperture and make short tunnel length after ACL reconstruction by comparing the femoral graft bending angle and tunnel length between the single-bundle (SB) transtibial (TT) and double-bundle (DB) transportal (TP) technique using three-dimensional-computed tomography using OsiriX^® imaging software. Methods: Forty-nine patients underwent an ACL reconstruction using a SB TT (Group I, 20 patients) and DB TP (Group II, 29 patients) technique. Femoral graft bending angle and femoral tunnel length were measured by CT image using OsiriX^® imaging software. Groups I and II were compared, and statistical analysis was performed using SPSS software. Results: The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angle of group II (111. 5 ± 8. 8° and 118. 9 ± 9. 8°, respectively) was significantly more acute than that of group I (125. 3 ± 11. 1°) (P < 0. 001, P = 0. 04). The mean femoral tunnel length of group I was significantly longer than that of group II (P = 0. 001). Conclusions: The femoral graft bending angle and the femoral tunnel length of the TP technique performed in the maximally flexed knee position was more acute and shorter than those of the TT technique after ACL reconstruction. This might increase the bending stress at the femoral tunnel aperture and shorter graft length in the tunnel after an ACL reconstruction using TP technique compared to the TT technique. Level of evidence: III.