We evaluate quantitative, positional, and individual differences on the proximity of ACL tibial footprint and the anterolateral meniscal root insertion (ALMR), and to investigate what could be used as an intraoperative landmark to prevent ALMR injury in this study.
Recent qualitative research has identified the proximity of the anterior cruciate ligament (ACL) tibial footprint to the anterolateral meniscal root insertion (ALMR), as well as its link to ALMR injury during tibial tunnel drilling for ACL reconstruction. To evaluate quantitative, positional, and individual differences on the proximity of ACL tibial footprint and ALMR, and to investigate what could be used as an intraoperative landmark to prevent ALMR injury.
Thirty-three non-paired fixed human cadaveric knees were evaluated. After the division and resection of outer fiber (OF) and inner fiber (IF) of ALMR, ACL bundles (anteromedial [AM] and posterolateral [PL] bundles) and the center of each attachment (OF, IF, AM, ACL, and PL) were marked with a radiopaque maker. Micro-computed tomography (µCT) was subsequently performed. Distance (AMOF, ACLOF, PLOF, AMIF, ACLIF and PLIF), relative positional relationship between OF/IF insertion, and AM/ACL/PL center were evaluated by a square grid on 3-dimensional (3D) CT images.
The AMOF, ACLOF, PLOF were 7.4 ± 1.5 mm, 8.2 ± 1.4 mm, and 10.3 ± 1.9 mm, respectively, and the AMIF, ACLIF, PLIF were 8.0 ± 1.3 mm, 6.3 ± 1.0 mm, and 6.3 ± 1.2 mm, respectively. There was no significant difference between the AMOF and ACLOF (P = 0.16) nor ACLIF and PLIF (P = 0.99), but both were significantly shorter than the PLOF or AMIF, respectively (both P<0.001). Compared to the IF, the insertion of the OF varied significantly more in the medial-lateral direction (P<0.004). Aside from two cases, the center of the OF/IF was located laterally to the ML center of the medial and lateral intercondylar tubercle (MIT/LIT).
The ACL tibial footprint and ALMR are in close proximity, particularly the AM and OF, PL and IF, and ACL center and OF/IF. The OF is variable, exhibiting proximity in some cases. MIT and LIT were useful landmarks for ALMR injury prevention.