Anterior Cruciate Ligament Injury
Pronounced: an-TEER-ee-or KROO-shee-ate ligament
by Carrie Myers Smith
An anterior cruciate ligament (ACL) injury is a tear in the ACL ligament. The ACL is located in the middle of the knee joint. It connects the lower leg bone to the thigh bone. It stabilizes the knee and prevents the lower leg bone from sliding too far forward at the knee.
The ACL ligament can become strained or torn when a strong force is applied to it. This can happen during sports or other high-stress activity.
Treatment depends on the severity of the injury.
ACL injury occurs when your knee gets twisted or during a hard landing from a jump. It can also happen with:
Risk Factors TOP
ACL injuries are more common in women. Other factors that increase your chance of ACL injury include:
Symptoms may include:
The doctor will ask about your symptoms and how you injured your knee. A physical exam will be done.
Tests may include:
Ligament sprains are graded according to their severity:
Talk with your doctor about the best treatment plan for you. Recovery time ranges depending on the grade of your injury. Treatment steps may include:
Your ligament will need time to heal. Avoid activities that place extra stress on the knee:
Your doctor may recommend a knee brace to stabilize the knee, and crutches to keep extra weight off your leg.
Apply an ice or a cold pack to the area for 15-20 minutes, four times a day, for several days after the injury. Do not apply the ice directly to your skin. Wrap the ice or cold pack in a towel.
Pain Relief Medications
To manage pain, your doctor may recommend:
Compression can help prevent more swelling. Your doctor may recommend an elastic compression bandage around your knee. Be careful not to wrap the bandage too tight.
Elevation can also help keep swelling down. Keep your knee higher than your heart as much as possible for the first 24 hours or so. A couple of days of elevation might be recommended for severe sprains.
Use heat only when you are returning to physical activity. Heat may then be used before stretching or getting ready to play sports to help loosen the ligament.
When the acute pain is gone, start gentle stretching as recommended. Stay within pain limits. Hold each stretch for about 10 seconds and repeat six times. Stretch several times a day.
Begin strengthening exercises for your ligaments as recommended.
If you are diagnosed with a ACL injury, follow your doctor's instructions.
Surgery may be needed to fully restore function of the knee. The decision to have surgery should be made after discussion with your doctor about your athletic needs, age, and associated factors.
To reduce your chance of injuring the ACL, take these steps:
American Academy of Orthopaedic Surgeons
American Orthopaedic Society for Sports Medicine
Canadian Orthopaedic Association
Canadian Orthopaedic Foundation
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Anterior cruciate ligament injuries: treatment and rehabilitation. Encyclopedia of Sports Medicine and Science website. Available at: http://sportsci.org/encyc/aclinj/aclinj.html . Accessed May 3, 2013.
ACL Injury: Does It Require Surgery? American Academy of Orthopaedic Surgeons website. Available at: http://orthoinfo.a... . Updated September 2009. Accessed May 3, 2013.
Griffin LY, Agel J, et al. Noncontact anterior cruciate ligament injuries: risk factors and prevention strategies. J Am Acad Orthop Surg . 2000;8:141-150.
Knee sprains and meniscal injuries. Merck Manual for Health Care Professionals. Available at: http://www.merckma... . Updated February 2012. Accessed May 3, 2012.
Ligament injuries to the knee. John Hopkins Medicine website. Available at. http://www.hopkins... . Accessed May 3, 2013.
7/6/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Prodromos CC, Han Y, et al. A meta-analysis of the incidence of anterior cruciate ligament tears as a function of gender, sport, and a knee injury-reduction regimen. Arthroscopy . 2007;23:1320-1325.
Last reviewed March 2013 by John C. Keel, MD
Last Updated: 3/1/2013