An ACL injury is the tearing of the anterior cruciate ligament (ACL) in your knee. A ligament is a strong band of tissue that connects one bone to another. The ACL connects the thighbone (femur) to the shinbone (tibia), which helps stabilize the knee. ACL injuries usually occur during sports and fitness activities that cause a person to slow down or change direction quickly. Landing awkwardly from a jump, a football tackle, or a motor vehicle accident can all also injure the ACL. Symptoms that occur when an ACL injury occurs include a loud “pop” sound, severe pain that prevents continued activity, and swelling and instability of the knee. Risk factors include playing in high contact sports, such as American football, and gender. Women are significantly more likely to have an ACL injury due to a strength imbalance between the muscles at the front of the thigh (quadriceps) and the muscles at the back of the thigh (hamstrings).
ACL injuries are typically diagnosed with a physical exam. The doctor will check for swelling and tenderness in the knee and may also move the knee into a variety of positions to determine if the ACL is torn. Images from X-rays, ultrasounds or MRIs may be needed to confirm the diagnosis. Treatment for ACL injuries begins with reducing the swelling and strengthening the muscles around the knee. The doctor will then decide if surgical repair of the ligament with rehabilitation is needed, or if rehabilitation alone is enough to treat the injury. Rehabilitation therapy may include the use of crutches, a knee brace, exercises to regain motion in the knee, and muscle-strengthening and stability exercises. If you have been diagnosed with an ACL injury, talk with your doctor to discuss the treatment plan that is best for you.