Reproducibility of the native ACL mid-substance cross-sectional area in anatomical single bundle ACL reconstruction.

PURPOSE: The purpose of this study was to evaluate the reproducibility of the native anterior cruciate ligament (ACL) mid-substance cross sectional area in anatomic single-bundle ACL reconstruction.

METHODS: Fifty-eight subjects who were performed anatomic single-bundle ACL reconstruction were included. Cross section size of the ACL graft was calculated from the graft diameter during surgery. Computed tomography (CT) of the knee was performed pre-operatively. Following Iriuchishima's report, native ACL size was estimated from the axial CT image of intercondylar notch area of femur at the most distal level of Blumensaat's line (In the report, native ACL size was equal to 14% of the intercondylar notch area of femur). The measured ACL graft cross-sectional size and estimated native ACL size were compared and correlation was evaluated.

RESULTS: Measured ACL graft cross-sectional size was 49 ± 14 mm2 . Measured intercondylar notch area of femur at the most distal level of Blumensaat's line was 372 ± 91.6 mm2 , and estimated native ACL size was 53 ± 12.5 mm2 . Measured ACL graft cross-section and estimated native ACL showed no significant size difference. Measured ACL graft cross-section and estimated native ACL had no significant size correlation.

CONCLUSION: Native ACL cross-sectional size was reproduced in anatomic single-bundle ACL reconstruction. However, as measured ACL graft and estimated native ACL showed no size correlation, it is possible that size of native ACL might not be reproduced. Such cases would be susceptible to the risk of graft impingement or knee instability.