Evaluation of the tunnel placement in the anatomical double-bundle ACL reconstruction: a cadaver study

The objective of this study was to investigate the accurate AM and PL tunnel positions in an anatomical double-bundle ACL reconstruction using human cadaver knees with an intact ACL. Fifteen fresh-frozen non-paired adult human knees with a median age of 60 were used. AM and PL bundles were identified by the difference in tension patterns. First, the center of femoral PL and AM bundles were marked with a K-wire and cut from the femoral insertion site. Next, each bundle was divided at the tibial side, and the center of each AM and PL tibial insertion was again marked with a K-wire. Tunnel placement was evaluated using a C-arm radiographic device. For the femoral side assessment, Bernard and Hertel's technique was used. For the tibial side assessment, Staubli's technique was used. After radiographic evaluations, all tibias' soft tissues were removed with a 10% NaOH solution, and tunnel placements were evaluated. In the radiographic evaluation, the center of the femoral AM tunnel was placed at 15% in a shallow-deep direction and at 26% in a high-low direction. The center of the PL bundle was found at 32% in a shallow-deep direction and 52% in a high-low direction. On the tibial side, the center of the AM tunnel was placed at 31% from the anterior edge of the tibia, and the PL tunnel at 50%. The ACL tibial footprint was placed close to the center of the tibia and was oriented sagittally. AM and PL tunnels can be placed in the ACL insertions without any coalition. The native ACL insertion site has morphological variety in both the femoral and tibial sides. This study showed, anatomically and radiologically, the AM and PL tunnel positions in an anatomical ACL reconstruction. We believe that this study will contribute to an accurate tunnel placement during ACL reconstruction surgery and provide reference data for postoperative radiographic evaluation.