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

Three-Dimensional Kinematic and Kinetic Analysis of Knee Rotational Stability After Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction

Purpose: To investigate whether anatomic restoration of the anterior cruciate ligament (ACL) functional bundles results in significant reduction in transverse-plane instability compared with the conventional single-bundle technique during a dynamic 60 pivoting maneuver with the supporting knee in extension. Methods: Using an 8-camera optoelectronic system and a force plate, we examined 10 patients with double-bundle ACL reconstruction, 12 patients with single-bundle reconstruction, 10 ACL-deficient subjects, and 10 healthy control individuals. The 4 groups did not differ in terms of age, body mass index, duration of follow-up, and number of meniscectomies performed. Kinematic and kinetic data were collected from these subjects while performing a pivoting maneuver on each side with the supporting knee in extension. Maximum range of motion for internal-external knee rotation and maximum knee rotational moment were examined. Results: There was no significant difference in tibial rotation either between the 4 groups or between sides. The mean knee rotation for the single-and double-bundle groups was lower than the control group. Rotational moment values were substantially reduced on the affected side of the reconstructed and the ACL-deficient groups. However, rotational moment was not found to affect the degree of angular displacement significantly. Conclusions: Double-bundle ACL reconstruction does not reduce knee rotation further compared with the single-bundle reconstruction technique. The affected side of ACL-deficient or -reconstructed individuals is subjected to reduced knee rotational moments compared with the intact side during stressful functional maneuvers. Level of Evidence: Level III, retrospective comparative study