Artificial anterolateral ligament reconstruction provides similar knee kinematics as compared to an autologous reconstruction and a lateral extra‐articular tenodesis

PURPOSE: We biomechanically compared three anterolateral procedures (artificial-anterolateral ligament [ALL] reconstruction, autologous-ALL reconstruction and lateral extra-articular tenodesis [LET]) in knees with anterior cruciate ligament (ACL) and anterolateral complex (ALC) injuries when combined with nonanatomic artificial ACL reconstruction. METHODS: Eight cadaveric knees were tested robotically at time-zero: (1) intact, (2) ACL + ALC deficient, (3) ACL reconstruction + artificial-ALL reconstruction, (4) ACL reconstruction + autologous-ALL reconstruction, (5) ACL reconstruction+LET. Each state was tested under 3 loads: (1) a 89N anterior tibial (AT) loading to test AT translation (ATT) at full extension (FE), 30°, 60° and 90°, (2) a 5N·m internal rotation (IR) tibial torque to test tibial IR at FE, 15°, 30° and 45°, (3) a simulated pivot-shift test consisting of a combined 5 N·m IR tibial torque and 7 N·m valgus load to test ATT and IR at FE, 15°, 30° and 45°. RESULTS: ACL + ALC deficiency impaired anteroposterior and rotational knee stability across all conditions. Under 89 N AT loading, the anterior instability was fully restored by ACL reconstruction + artificial-ALL reconstruction (n.s.) and partially by ACL reconstruction + autologous-ALL reconstruction and ACL reconstruction + LET, with significant differences from the intact state at 30° (p = 0.019) and 60° (p = 0.011) in the ACL reconstruction + autologous-ALL reconstruction state and at 30° (p = 0.032) and 60° (p = 0.018) in the ACL reconstruction+LET state. Under 5 N·m IR tibial torque, the internal rotational instability was fully restored by ACL reconstruction+artificial-ALL reconstruction and ACL reconstruction + LET (n.s.) and partially by ACL reconstruction + autologous-ALL reconstruction, with significant differences from the intact state at FE (p = 0.044) and 15° (p = 0.049). During simulated pivot-shift testing, all three procedures fully restored native kinematics with no significant differences observed (n.s.). CONCLUSIONS: Artificial-ALL reconstruction, autologous-ALL reconstruction, and LET similarly restored native knee kinematics in ACL + ALC deficient knees when combined with artificial ACL reconstruction at time-zero. LEVEL OF EVIDENCE: Level V, laboratory study.