Anterior cruciate ligament (ACL) i... Health Article

Causes

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.

Symptoms

Early symptoms:

• A "popping" sound at the time of injury
• Knee swelling within 6 hours of injury
• Severe pain

Late symptoms:

• Arthritis
• Knee joint instability

First Aid

An ACL injury should be treated with:

• A splint
• Elevating the joint (above the level of the heart)
• Ice
• Pain relievers such as nonsteroidal anti-inflammatory drugs (like ibuprofen)

Do not play again until you have been evaluated and treated.

Some people may need crutches to walk until the swelling and pain have improved. Physical therapy may help you regain joint motion and leg strength.

If you still have instability after your leg strength and knee motion have returned, your doctor may recommend a reconstruction of the ACL. The old ligament cannot be fixed, so a new one needs to be constructed. Common grafts used for reconstruction include:

• A piece of the tendon that connects the kneecap to the tibia (patellar tendon)
• Hamstring tendon
• Human cadaver graft

Do Not

• In the case of a serious knee injury, do not try to move the joint. Use a splint to keep the knee straight until a trained medical professional has evaluated it.
• Do not return to play until you have been evaluated and treated.

Call immediately for emergency medical assistance if

Anyone with a serious knee injury should seek medical attention for x-rays and evaluation.

If the foot is cool and blue after a knee injury, the knee may be dislocated and blood vessels to the foot may be injured. This is a true medical emergency that requires immediate professional help.