Tibial Rotation Under Combined In Vivo Loading After Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction
Purpose: To evaluate in vivo the differences in tibial rotation between single-and double-bundle anterior cruciate ligament (ACL)-reconstructed knees under combined loading conditions. Methods: An 8-camera optoelectronic system and a force plate were used to collect kinematic and kinetic data from 14 patients with double-bundle ACL reconstruction, 14 patients with single-bundle reconstruction, 12 ACL-deficient subjects, and 12 healthy control individuals while performing 2 tasks. The first included walking, 60 degrees pivoting, and stair ascending, and the second included stair descending, 60 degrees pivoting, and walking. The 2 variables evaluated were the maximum range of internal-external tibial rotation and the maximum knee rotational moment. Results: Tibial rotation angles were not significantly different across the 4 groups (P=.331 and P=.851, respectively) or when side-to-side differences were compared within groups (P=.216 and P=.371, respectively) for the ascending and descending maneuvers, nor were rotational moments among the 4 groups (P=.418 and P=.290, respectively). Similarly, for the descending maneuver, the rotational moments were not significantly different between sides (P=.192). However, for the ascending maneuver, rotational moments of the affected sides were significantly lower by 20.5% and 18.7% compared with their intact counterparts in the single-bundle (P=.015) and double-bundle (P=.05) groups, respectively. Conclusions: High-intensity activities combining stair ascending or descending with pivoting produce similar tibial rotation in single-and double-bundle ACL-reconstructed patients. During such maneuvers, the reconstructed knee may be subjected to significantly lower rotational loads compared with the intact knee. Level of Evidence: Level III, retrospective comparative study.