In the setting of rotatory knee instability following anterior cruciate ligament (ACL) reconstruction, there has been a resurgence of interest in knee's anterolateral complex (ALC). Reconstruction or augmentation of the ALC with procedures such as a lateral extra-articular
tenodesis (LET) has been proposed to reduce rotatory knee instability in conjunction with ACL reconstruction. The current review investigates the recent literature surrounding the role of the ALC in preventing rotatory knee instability.
RECENT FINDINGS: The knee's anterolateral complex (ALC) is a complex structure composed of the superficial and deep portions of the iliotibial band, the capsulo-osseous layer, and the anterolateral
capsule. Distally, these various layers merge to form a single functional unit which imparts stability to the lateral knee. While the iliotibial band and the
capsule-osseous layer have been shown to be primary restraints to rotatory motion after
ACL injury, the biomechanical role of the anterolateral
capsule remains unclear. Biomechanical studies have shown that the anterolateral
capsule and the anterolateral thickening of this
capsule act as a sheet of fibrous tissue which does not resist motion around the knee as other longitudinally oriented ligaments do. Augmentation of the ALC, with LET, has been performed globally for over 30 years. This procedure can decrease rotatory knee instability, but long-term studies have found little difference in patient-reported outcomes,
osteoarthritis, or ACL reconstruction failure with the addition of LET. Further research is needed to clarify indications for the clinical use of ALC-based procedures.