Introduction: Various ligaments, menisci and retinaculae are reported in an MRI of the knee joint coming for a suspected internal derangement of knee. The contributory role of the anterolateral ligament (ALL) in maintaining knee stability however has not been adequately studied as yet, and therefore not routinely reported. Purpose: To assess MRI appearance of this anterolateral ligament (ALL), its femoral, meniscal and tibial components and attachments. And to evaluate its associations with other internal derangements of the knee like anterior cruciate ligament (ACL) tear and meniscal tear. Materials and methods: A total of 25 MRI knee studies interpreted as normal will be reviewed to characterize the anterolateral ligament. A further 25 MRI knee with internal derangement injuries will be studied to assess the association of ALL with other internal derangements. Patients referred for knee MRI with clinically suspected internal derangements will be included in this study. Patients suffering from claustrophobia, incompatible metallic hardware and postoperative knee patients were excluded from the study. Results: Among the 25 patients whose MRI was normal, the anatomy was fairly established and correlated with prior studies. The femoral attachment was seen to merge with the anterior aspect of the fibular collateral ligament in all cases. Among the 25 patients who were diagnosed with MR of having various internal derangements, the largest association was found to be with anterior cruciate ligament injuries. One patient with a bucket handle tear of the body of lateral meniscus had a complete tear of the ALL. Further one patient with a Segond’s fracture had a tibial avulsion of the ALL. Conclusion: With this study, we were able to more assertively establish the anatomy and attachments of the relatively unexplored anterolateral ligament. The anterolateral ligament injuries were found to have a strong association with tears of the anterior cruciate ligament, flipped tears of the body of lateral meniscus as well as Segond’s fracture.
