Biomechanical function of the anterolateral ligament of the knee: a systematic review

Background It has been suggested that the anterolateral ligament (ALL) is an important anterolateral stabilizer of the knee joint which functions to prevent anterolateral subluxation and anterior subluxation at certain flexion angles in the knee. Purpose To analyze and systematically interpret the biomechanical function of the ALL. Methods An online search was conducted for human cadaveric biomechanical studies that tested function of the ALL in resisting anterolateral subluxation and anterior subluxation of the knee. Two reviewers independently searched Medline, Embase, and the Cochrane Database of Systematic Reviews for studies up to 25 September 2018. Biomechanical studies not reporting the magnitude of anterior tibial translation or tibial internal rotation in relation to the function of the ALL were excluded. Results Twelve biomechanical studies using human cadavers evaluating parameters including anterior tibial translation and/or internal tibial rotation in anterior cruciate ligament (ACL)-sectioned and ALL-sectioned knees were included in the review. Five studies reported a minor increase or no significant increase in anterior tibial translation and internal tibial rotation with further sectioning of the ALL in ACL-deficient knees. Five studies reported a significant increase in knee laxity in tibial internal rotation or pivot shift with addition of sectioning the ALL in ACL-deficient knees. Two studies reported a significant increase in both anterior tibial translation and internal tibial rotation during application of the anterior-drawer and pivot-shift tests after ALL sectioning. Conclusion There was inconsistency in the biomechanical characteristics of the ALL of the knee in resisting anterolateral and anterior subluxation of the tibia.