[Magnetic resonance imaging and the discoid meniscus in children]

Discoid meniscus is an uncommon dysplasia generally affecting the lateral meniscus. Its congenital or acquired origin remains a question of debate. We report 5 cases or lateral discoid meniscus in 4 girls and 1 boy, aged from 6 to 11 years. The main clinical signs were snapping knee and pain. The discoid meniscus appeared in MRI as an abnormally large meniscus extending into the joint space. It appeared as a central band giving increased signal in 3 out of 5 cases. The significance of this probably trauma-induced image was uncertain. Surgery confirmed MRI findings in 4 cases in which total resection of the meniscus was performed. No operation was performed in the fifth case.