However, the majority of patients who have injured their ACL will experience a substantial amount of pain.
The ACL prevents the tibia from sliding too far forward from underneath the femur. The ACL originates in a large notch at the end of the femur and runs diagonally to insert on the top surface of the tibia.
It is one of two ligaments in the center of the knee (the other is the PCL), which helps connect the femur to the tibia. ACL stands for anterior cruciate ligament.