Anterior cruciate ligament (ACL) injury
An anterior cruciate ligament injury is the over-stretching or tearing of the anterior cruciate ligament (ACL) in the knee. A tear may be partial or complete.
ACL tears may be due to contact or non-contact injuries. A blow to the side of the knee, which can occur during a football tackle, may result in an ACL tear.
Coming to a quick stop, combined with a direction change while running, pivoting, landing from a jump, or overextending the knee joint (called hyperextended knee), also can cause injury to the ACL.
Basketball, football, soccer, and skiing are common causes of ACL tears.
- A "popping" sound at the time of injury
- Knee swelling within 6 hours of injury
- Pain, especially when you try to put weight on the injured leg
Those who have only a mild injury may notice that the knee feels unstable or seems to "give way" when using it.
Use proper techniques when playing sports or exercising. Several women's college sports programs have reduced ACL tears through a training program that teaches athletes how to minimize the stress they place on their ACL.
Although the issue is controversial, the use of knee braces during aggressive athletic activity (such as football) has not been shown to decrease the incidence of knee injuries and may give the player a false sense of security.