A biomechanical comparison of the main anterolateral procedures used in combination with anterior cruciate ligament reconstruction

BACKGROUND: None of the anterolateral procedures used in combination with ACL reconstruction (ACLR) to control rotational laxity have demonstrated superiority. The objective was to compare the capacity of the main anterolateral procedures associated with ACLR to restore intact knee kinematics in case of combined ACL and anterolateral structure injury. METHODS: The complete kinematics of 10 cadaveric knees, previously modelled by TDM, were recorded using a 3D Motion Analysis® system. Intact knee kinematics, including internal rotation (IR) of the tibial and anterior-posterior (AP) laxity at 30 and 90° flexion were initially assessed, followed by a sequential section of the ACL and anterolateral complex (ALC) (anterolateral ligament (ALL), ALL capsule and Kaplan fibers). After the ACLR, 5 anterolateral procedures were performed consecutively on the same knee: ALLR; Ellison; Deep Lemaire; Superficial Lemaire; and MacIntosh. The last three procedures were randomized. For each procedure, the graft was fixed in neutral rotation at 30° flexion with a tension of 20 N. RESULTS: ACLR alone did not restore overall knee kinematics when there was an ACL+ALC injury, and resulted in residual rotational laxity of the tibia (p > 0.001). Only the ALLR (p=0.262) and modified Ellison (p=0.081) procedures restored normal global IR kinematics. Superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinematic profiles (respectively: p=0.013, p=0.018 and p=0.030). In terms of ACLR, the addition of an anterolateral procedure did not provide additional control over AP translation at 30 and 90° (p > 0.05), exception for the surficial Lemaire procedure at 90° (p = 0.032). DISCUSSION: ACLR alone was not sufficient to restore normal kinematics in ACL and ALC-deficient knees. ALLR and Ellison procedures restored physiological kinematics, unlike the MacIntosh procedure which caused additional control of IR and thereby induced over-constraint. CONCLUSION: The addition of ALLR or the modified Ellison procedure, which restore intrinsic kinematics, might be useful during primary ACL reconstruction to avoid repeated injury without a risk of over-constraint. The superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinetics but provided additional rotation control that could be useful in revision surgery.