Assessment of the anterolateral ligament of the knee by 1.5 T magnetic resonance imaging

Objective This study was performed to evaluate the visibility of the knee's anterolateral ligament (ALL) by magnetic resonance (MR) imaging when evaluating injuries of the ALL in relation to injuries of the anterior cruciate ligament (ACL). Methods Two reviewers retrospectively analyzed MR images for the visibility and dimensions of the ALL and the relationship between ALL and ACL injuries. The intraclass correlation coefficient (ICC) and kappa analysis were used to assess interobserver reliability. The chi-square test was used to assess the relationship between ALL and ACL injuries. Results The entire ALL was viewed on 82% of all MR images. The ICC for ALL visualization ranged from moderate to perfect between the two readers. There was almost perfect agreement between the reviewers when evaluating ALL dimensions. The mean lengthstandard error, median thickness, and mean width +/- standard error of the ALL were 36.5 +/- 0.6 mm, 2.5 mm, and 8.2 +/- 0.2 mm, respectively. A statistically significant relationship was observed between ALL and ACL injuries. Conclusion The ALL was visible on most MR images, allowing ALL injuries to be noted during routine MR image interpretation. Radiologists should note concomitant ACL and ALL injuries as part of their assessments.