Editorial Commentary: Another Take on the Anterolateral Ligament: High-Grade Are Worse Than Low-Grade Injuries, But...

The anatomy, function, and existence of the anterolateral ligament (ALL) is still hotly debated and a controversial topic. Currently both basic biomechanical and clinical studies are not providing sufficient and strong evidence to either support or refute that the ALL plays an important role for knee stability. One could argue that stability is provided by the anterolateral complex, including the iliotibial band, Kaplan fibers, and the anterolateral capsule, which may contain a structure called the ALL. Magnetic resonance imaging (MRI) is routinely performed in patients with anterior cruciate ligament (ACL) injury, but unfortunately ALL injuries cannot be reliably diagnosed in patients with concomitant ACL tears. When dividing ALL injuries into high and low grade using preoperative MRI and investigating clinical outcomes after double-bundle ACL reconstruction, patients with high-grade injuries have inferior outcomes and a significantly greater revision rates. However, the limitations of this research reduce the validity of these conclusions: high rate of loss to follow-up above accepted standard, unequal size of their study groups, fragility index of zero, the inaccuracy of diagnosing ALL injuries in the presence of ACL tears on MRI, and the dilemma with randomly classifying high- and low-grade ALL injury based on MRI.