The Anterolateral ligament is a new discovery by Dr. Steven Claes from Belgium with his recently published article in the Journal of Anatomy in 2013.  This new ligament controls internal rotation of the knee and works in conjuction with the ACL.  Much of the new research indicates that the ALL is an important structure, and if left untreated, will result in the ACL having to sustain loads 6x greater than normally seen in rotational stress.  This will result in failure of ACL reconstructions and repairs.  MRI is unreliable to see damage to the ALL and requires an ultrasound evaluation and a physical examination to determine whether there has been damage to the ALL.