Anterior Cruciate Ligament Tunnel Placement

The purpose of this cadaveric study was to analyze variation in anterior cruciate ligament (ACL) tunnel placement between surgeons and the influence of preferred surgical technique and surgeon experience level using three-dimensional (3D) computed tomography (CT). In this study, 12 surgeons drilled ACL tunnels on six cadaveric knees each. Surgeons were divided by experience level and preferred surgical technique (two-incision [TI], medial portal [MP], and transtibial [TT]). ACL tunnel aperture locations were analyzed using 3D CTscans and compared with radiographic ACL footprint criteria. The femoral tunnel location from front to back within the notch demonstrated a range of means of 16% with the TI tunnels the furthest back. A range of means of only 5% was found for femoral tunnel low to high positions by technique. The anterior to posterior tibial tunnel measure demonstrated wider variation than the medial to lateral position. The mean tibial tunnel location drilled by TT surgeons was more posterior than surgeons using the other techniques. Overall, 82% of femoral tunnels and 78% of tibial tunnels met all radiographic measurement criteria. Slight (1-7%) differences in mean tunnel placement on the femur and tibia were found between experienced and new surgeons. The location of the femoral tunnel aperture in the front to back plane relative to the notch roof and the anterior to posterior position on the tibia were the most variable measures. Surgeon experience level did not appear to significantly affect tunnel location. This study provides background information that may be beneficial when evaluating multisurgeon and multicenter collaborative ACL studies.