How does the ACL become injured?
The ACL’s main function is to limit abnormal motion between the tibia and femur. From an athletic and functional perspective, it serves mainly a rotational role. It has a very minimal and limited role with linear activities such as walking and cycling – but is critical to activities that require sudden starts or stops, cutting, pivoting, jumping and changing direction. Therefore, ACL injuries are most commonly seen in athletes who participate in sports that require such movements. Ball (football, soccer, basketball, lacrosse….), racquet, frisbee and snow sports are the main culprits.
ACL injuries can range in severity from a small sprain or stretching of the ligament, to a partial tear or a complete tear. If the ligament is stretched beyond its normal range, the tibia can slip out from under the femur. The strong, rope-like tissue of the ligament can then stretch, tear or break.