Definition
By Mayo Clinic staffAn ACL injury is the tearing of the anterior cruciate (KROO-she-ate) ligament, or ACL, inside your knee joint. An ACL injury most commonly occurs during sports that involve sudden stops and changes in direction — such as basketball, soccer, tennis and volleyball.
Immediately after an ACL injury, your knee may swell, feel unstable and become too painful to bear weight. Many people hear or feel a "pop" in their knee when an ACL injury occurs.
Depending on the severity of your ACL injury, treatment may include surgery to replace the torn ligament followed by rehabilitation exercises to help you regain strength and stability. If your favorite sport involves pivoting or jumping, a proper training program may help reduce your chances of an ACL injury.
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- Friedberg RP. Anterior cruciate ligament injury. http://www.uptodate.com /index. Accessed Oct. 25, 2012.
- ACL injury: Does it require surgery? American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00297. Accessed Oct. 25, 2012.
- DeLee JC, et al. DeLee & Drez's Orthopaedic Sports Medicine: Principles and Practice. 3rd ed. Philadelphia, Pa.: Saunders Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-1-4160-3143-7..X0001-2--TOP&isbn=978-1-4160-3143-7&uniqId=230100505-57. Accessed Oct. 25, 2012.
- Anterior cruciate ligament (ACL) injury prevention. American Orthopaedic Society for Sports Medicine. http://www.sportsmed.org/Patient/Sports_Tips/AOSSM_Sports_Tips_Sheets. Accessed Oct. 25, 2012.


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