Athletes are often involved in sports where pivoting and twisting are routine. Sometimes the knee gives way during these activities and the ACL of the knee is torn. ACL is short for Anterior Cruciate Ligament. Anterior means front, cruciate means crossing and ligaments hold two bones together. So the ACL is the front crossing ligament of the knee. Its purpose is to keep the shin bone (tibia) from sliding forward during rigorous activities. It passes through the knee much like a rope, so when torn it sags and cannot re-establish its tension and heal.
When injury occurs there is often a “pop” and swelling. Diagnosis is made by exam where the knee is more loose in one direction. MRI can confirm the suspected injury. If one does not participate in pivoting sports, they may do well since demands on the knee are not great. However, most patients who injure the ACL are active in sports. That is how they came to injure the ligament. If they continue to participate in risky sports, it is likely their knee will give way again. When this happens, they may cause further injury to the knee.
Treatment for ACL tears has evolved over time. Braces and strengthening can be successful in some patients. Most patients who want to resume pivoting sports will have the highest success rate with surgery. Years ago surgeons would try to repair the ligament with stitches. It did not work out well since stitches can only be so strong and the ligament was frequently stretched and shredded. Currently surgeons remove the damaged ligament and replace it with a “graft”. Much of the procedure is performed using an arthroscope. The damaged ACL is removed, holes or “tunnels” are drilled into the bones where the ACL attached, and the graft or new ligament is threaded through the tunnels to create the new ACL. There are several choices for the graft to replace the ACL. Dr. Steensen prefers to use two of the patient’s hamstring tendons in most cases. This is typically an outpatient procedure and patients use a knee brace and crutches for a short time. An exercise program after surgery helps return patients to activity.