The ABCs of the anterior cruciate ligament: a primer for magnetic resonance imaging assessment of the normal, injured and surgically repaired anterior cruciate ligament.

This article reviews the magnetic resonance imaging (MRI) findings of the native and reconstructed anterior cruciate ligament (ACL). MRI is the most accurate non-invasive modality to evaluate the ACL. Tears of the ACL manifest with direct and indirect signs. The reconstructed ACL has several complications including re-tear and anterior arthrofibrosis, which are also accurately assessed using MRI.