Change of the tunnel configuration in the non-anatomic trans-tibial double bundle ACL reconstruction.

Background: The objectives of this study were to evaluate tunnel widening and morphologic change at the tunnel aperture.

Methods: A prospective study that included 17 trans-tibial double bundle anterior cruciate ligament (ACL) patients was conducted for the evaluation of serial computed tomography (CT) scan. The OsiriX was used for remodeling of CT images with a tunnel direction. Tunnel widening and change of the aperture morphology were assessed.

Results: With regard to the comparison of tunnel widening of the anteromedial (AM) tunnel, the entrance (p=0.01) and mid (p=0.02) of the coronal image, and the entrance (p < 0.01) and mid (p < 0.01) of the sagittal image showed statistically significant differences. The entrance (p=0.01) of the sagittal image only showed statistical significance in the posterolateral (PL) tunnel. With regard to the comparison between the AM and PL tunnels, the mid-portion (p = 0.04) of the sagittal image showed statistical differences, and the AM tunnel showed larger widening than the PL tunnel. Change of tunnel aperture was observed in the posterior, medial, and lateral portions of the AM tunnel and the anterior, posterior, and lateral portions of the PL tunnel.

Conclusions: In some aspects, occurrence of tunnel widening was observed in most sites. Widening occurred mainly at the entrance and mid-portions of the AM tunnel and the entrance of the PL tunnel. Change of tunnel aperture was observed at most directions in both tunnels. This is a non-anatomic ACL reconstruction and similar study with anatomic ACL reconstruction would be required in the future.