ACL avulsion fractures are associated with which other injuries?
"Kissing" bone contusions; MCL tear; PCL tear.
Why is accurate classification of ACL avulsion fractures necessary?
The higher the grade of injury the more likely the need for surgical intervention - type 1 are usually treated conservatively; type 2 usually require arthroscopic treatment and types 3 and 4 usually require internal fixation.
The diagrams illustrate the hinged appearance of type 2 ACL avulsion fractures (which is elevated anteriorly but not posteriorly) as well as the proposed mechanism.