The Anterior Cruciate Ligament (ACL) is an important ligament located in the middle of your knee joint. Its role is to help keep you knee stable, especially when performing ‘cutting’ movements like running from side to side or swift changes in direction.
An ACL injury is the tearing of the anterior cruciate ligament in your knee. An ACL injury may make your knee feel unstable or loose, and your knee feels like it “gives way”.
Diagram of a tear of the Anterior Cruciate Ligament