ACL injuries are among the most common sport related knee injuries. Approximately 100,000 – 200,000 people in the United States acquire a torn or ruptured ACL every year. But what exactly is the ACL, and how is it injured?
The ACL is a strong ligament in the knee known as the anterior cruciate ligament. It runs anterior from the femur to the tibia connecting the two bones together. The ACL’s purpose is to control movement at the knee joint. It limits side to side motion at the knee as well as prevents the knee from extending beyond its normal range of motion.
ACL injuries often occur during athletic activities such as soccer, football, and skiing. They mostly happen when one stops suddenly with the foot planted firmly on the ground. This action causes an over extension of the knee with the tibia moving too far forward on the femur. This stresses the ACL beyond its normal limits causing a tear of the ligament.