Summary

normal ALL description on MRI, ALL volume is greater in men than women

Abstract

Aim

To describe the normal morphology of the anterolateral ligament (ALL) of the knee in individuals without ligamentous injury in magnetic resonance imaging (MRI). Method: A descriptive study. One hundred MRI were reviewed retrospectively from June 2016. Were included patients between 15 and 45 years with no history of giving away or knee surgeries. Patients were excluded patients if MRI showed signal or morphology alteration in anterior cruciate ligament or posterior cruciate ligament or posterolateral corner structures or chondral damage (ICRS =2) or postsurgical changes in any MRI acquisition. Age, gender, presence of ALL, ALL leght, ALL width, ALL diameter, meniscal insertion and femoral and tibial distance to the joint line were recorded. The data were presented in median and interquartile range. Secondarily, the volume of ALL was calculate and compared by gender using median test for unpaired data. Stata v11.2 (StataCorp LP, College Station, Texas, USA) was used. Results: The ALL was present in 98 MRI, of which 96 (98%) was fully identified. The median length, width and thickness was 27mm [25-29], 6mm [5-8] and 1 mm [1-1.5] respectively. In 98 cases (100%) meniscal insertion was identified. The median ratio of tibial portion was 24% [22-29%] of the full lengh. In men the ALL volume was 218mm3, while in women it was 156mm3 [113-196], being statistically significant (p <0.00). The best view was obtained in coronal plane T1 acquisition. Conclusion: The presence of ALL is constant on MRI so its description must be done during MRI analysis. Femoral portion of ALL is larger than tibial portion, meniscal insertion is constant and ALL volume is greater in male than women.