Outperformance of Combined Artificial Anterolateral Ligament and ACL Reconstruction Compared With Isolated Artificial ACL Reconstruction in Knees With Anterolateral Structure and ACL Deficiency: A Biomechanical Analysis

Background: Despite the promising clinical outcomes of artificial polyethylene terephthalate (PET) ligaments in isolated anterior cruciate ligament reconstruction (ACLR), their biomechanical performance after combined anterolateral ligament reconstruction (ALLR)/ACLR in anterolateral structure (ALS)/anterior cruciate ligament (ACL)-deficient knees has not been investigated. Purpose/hypothesis: The purpose of this study was to compare biomechanical performance in cadaveric knees between combined artificial ALLR/ACLR and isolated artificial ACLR using PET ligaments. It was hypothesized that combined artificial ALLR/ACLR would restore native knee stability and outperform isolated artificial ACLR in ALS/ACL-deficient knees. Study design: Controlled laboratory study. Methods: Eight fresh-frozen cadaveric knees were tested using a robotic manipulator. Each knee was tested in 4 states: (1) ALS/ACL intact, (2) ALS/ACL deficient, (3) ACLR, and (4) ALLR/ACLR. The anterior tibial translation (ATT) and tibial internal rotation (IR) in each knee condition were measured under 3 loads: (1) 89 N of anterior tibial loading, (2) 5 N·m of IR torque, and (3) simulated pivot shift (combined 5 N·m of IR torque and 7 N·m of valgus load). Conclusion: Combined artificial ALLR/ACLR restored native knee stability across multiple flexion angles and outperformed isolated artificial ACLR in ALS/ACL-deficient knees, particularly with respect to ATT and tibial IR during the pivot-shift test. Clinical relevance: The indications of the artificial PET ligament may be expanded to include combined ALLR/ACLR to restore knee stability better than isolated artificial ACLR in ALS/ACL-deficient knees.