Magnetic resonance imaging assessment of the normal knee anterolateral ligament in children and adolescents

Abstract

Objective: To characterize the anterolateral ligament (ALL) in normal knees of pediatric patients by magnetic resonance imaging (MRI) and to establish the age at which it is possible to visualize its presence and whether there are differences between male and female populations. Materials and methods: MRI scans of patients younger than 18 years were retrospectively evaluated. The exams were performed in 1.5-T scanners. The ALL was characterized dichotomously as visualized or not visualized based on the assessment criteria of this structure in adult patients. The characterization of the ALL was divided according to sex and age. Results: A total of 363 knee MRI scans were evaluated, 200 from male and 163 from female patients. The ALL was more frequently visualized in coronal sequences. The mean ALL visualization in pediatric patients was 69.4% and was lower in younger patients and higher in patients close to 18 years. It was not possible to visualize the ALL in female patients younger than 7 years or in male patients younger than 6 years. In patients between 17 and 18 years of age, the ALL was visualized in 100% of cases in both sexes. Conclusions: Visualization of the ALL increased with age in both sexes. Only after age 13 in females and age 15 in males was visualization of the ALL close to 70%; thus, below these ages, we believe that the characterization of this structure with conventional protocols is still imprecise.