The anterior cruciate ligament, or ACL, is located in the interior of the knee and connects the thigh bone to the shin bone. It provides front-to-back stability for the knee. An ACL tear is a significant injury that most often occurs within high impact sports that involve jumping, pivoting and change of direction. An ACL tear requires surgery and extensive recovery. General rehabilitation time for an ACL tear is six months, and the recovery can be both physically and mentally challenging. STACK is the ultimate resource to help you get through an ACL injury and on the road to recovery.