The Anterior Cruciate Ligament (or ACL) is a major ligament of the knee that connects the femur to the tibia. The ACL’s main function is to prevent an anterior translation of the tibia on the femur, providing stability to the front of the knee joint. ACL injuries are one of the most common sports injuries and an estimated 1 out of 3,000 people will suffer from one in any given year. They are most often seen in high impact sports such as football, basketball, soccer, gymnastics and skiing. Women are typically more prone to ACL injuries because of their increased Q angle (the angle between the anterior superior iliac spine of the pelvis and the midline of the patella). The actions that can provoke an injury are sudden changes in direction, jumping, and a direct blow to the knee joint. Injuries can range from an overstretching or a sprain of the ligament, to a complete tear of the ACL. Symptoms of an ACL injury are swelling around the joint, pain and tenderness towards the outside of the knee, and instability or a feeling of the knee “giving way” with standing and walking. They are best diagnosed with an MRI.
Physical therapy is needed for mild sprains of the ACL and complete tears to help restore the stability of the knee and return the patient to normal function. For a mild to moderate sprain, the course of physical therapy can last anywhere from 6-10 weeks and will initially include modalities such as ice and ultrasound to reduce pain and swelling, manual therapy techniques, range of motion exercises and stretching exercises. As the injury begins to heal, the therapist will incorporate progressive strengthening, balance and agility training. Physical therapists will also analyze a patient’s gait and body mechanics to ensure that the patient’s quality of movement is safe, and that they will be able to return to prior activities and sports without risk of re-injury to the knee.
In the event of a complete tear of the ACL, depending on a person’s level of activity, surgical reconstruction may be indicated. Post-surgically, the patient will then have to wear a knee brace when walking and undergo an extensive course of physical therapy to strengthen the knee and ensure that the reconstruction is a success.