What Athletes Should Know About ACL Injuries

Gregory K. Johnson, MD
Board Certified Orthopedic Surgeon

Playing sports is a great way to stay in shape and have fun. But activities that involve sudden changes in direction, such as soccer, basketball, and tennis, can put you at risk for a particular type of knee injury: damage to the Anterior Cruciate Ligament, or ACL.

What is the ACL?
The ACL is one of four ligaments which stabilize the knee joint. Without ligaments to stabilize the knee, the joint would be unsteady and prone to dislocation. The ACL prevents the shinbone, or tibia, from sliding forward beneath the thighbone, or, femur. Of the four major ligaments of the knee, the ACL injury is the most common.

What are the symptoms of ACL injuries?
When an ACL injury occurs, the knee becomes less stable, or unstable. Often, the injury is a result of a hard twist or excessive pressure on the ligament, which causes it to tear. Symptoms of a severe and sudden ACL injury include:

1. Feeling or hearing a pop in the knee at the time of injury

2. The knee "buckling" or giving out after a jump or change in direction, or after a direct blow to the side of the knee

3. Pain on the outside and back of the knee

4. Knee swelling within the first few hours of the injury, or,

5. Limited knee movement because of swelling

How are ACL injuries treated?
It's important that an ACL injury is accurately diagnosed and treated. An untreated injury can leave you vulnerable to future problems such as chronic pain, decreased movement in the knee, cartilage tears, or arthritis. The goal of treatment is to return the knee to normal stability or at least stabilize it enough to suit your lifestyle. People with minor ACL injuries usually begin treatment with a physical rehabilitation program designed to build strength and flexibility in the quadriceps muscles on the front of the thigh, and to strengthen and tighten the hamstring muscles in the back of the thigh. More serious ACL injuries may require several months of rehabilitation, or surgery followed by several months of rehabilitation designed to strengthen leg muscles around the injured ACL. Recovery from an ACL injury varies with each individual. As a rule, treatment should continue until the knee is stable and strong, and not depend on a certain time limit.

What is the best prevention for ACL injuries?
The best way to prevent knee problems is to stretch and strengthen the leg muscles, especially the quadriceps and hamstrings. If you play an active sport, be sure to practice the proper technique for landing from a jump, and learn to do cutting maneuvers in a crouched posture with a slight bend at the knee and the hip. Finally, try to avoid factors such as wearing shoes with cleats in contact sports, and running downhill unless you are fully conditioned. Stay active, but protect your knees. Proper care and attention now can mean keeping your active lifestyle for as long as you see fit.