Purpose: The purpose of this study was to visualize and quantify the positions of femoral and tibial tunnels in patients who underwent traditional transtibial single-bundle ACL reconstruction, as performed by multiple surgeons, utilizing 3D CT models, and to compare these positions to our previously reported anatomical tunnel positions.
Methods: Fifty-eight knee computed tomography (CT) scans were performed on patients who underwent primary or revision transtibial single-bundle ACL reconstruction, and three-dimensional reconstructions of the CT scans were aligned within an anatomical coordinate system. The position of femoral tunnel aperture centers was measured with (1) the quadrant method and (2) in the anatomic posterior-to-anterior and proximal-to-distal directions. The position of tibia tunnel aperture centers were measured similarly, in the anterior-to-posterior and medial-to-lateral dimensions on the tibial plateau. Comparisons were made to previously established anatomical tunnel positions, and data were presented as "mean value ± standard deviation (range)."
Results: The location of tibial tunnels was at 48.0 ± 5.4% (35.6-59.5%) of the anterior-to-posterior plateau depth and at 47.9 ± 2.9% (42.2-57.4%) of the medial-to-lateral plateau width. The location of femoral tunnels was at 55.8 ± 8.0% (41.5-79.5%) in the anatomic posterior-to-anterior direction and at 41.2 ± 10.4% (15.1-67.4%) in the proximal-to-distal directions. Utilizing a quadrant method, femoral tunnels were positioned at 37.4 ± 5.1% (24.9-50.6%) from the proximal condylar surface, parallel to Blumensaat line, and at 11.0 ± 7.3% (-6.0-28.7%) from the notch roof, perpendicular to Blumensaat line. In summary, tibial tunnels were positioned medial to the anatomic PL position (p < 0.001), and femoral tunnels were positioned anterior to both AM and PL anatomic tunnel locations (p < 0.001 and p < 0.001).
Conclusion: ACL reconstruction via traditional transtibial technique fails to accurately position femoral and tibial tunnels within the native ACL insertion site. To achieve anatomical graft placement, other surgical techniques should be considered.
Level of evidence: IV.