Overview

An ACL injury is the tearing of the anterior cruciate (KROO-she-ate) ligament (ACL) — one of the major ligaments in your knee. ACL injuries most commonly occur during sports that involve sudden stops, jumping or changes in direction — such as basketball, soccer, football, tennis, downhill skiing, volleyball and gymnastics.

Many people hear or feel a "pop" in the knee when an ACL injury occurs. Your knee may swell, feel unstable and become too painful to bear weight.

Depending on the severity of your ACL injury, treatment may include rest and rehabilitation exercises to help you regain strength and stability or surgery to replace the torn ligament followed by rehabilitation. A proper training program may help reduce the risk of an ACL injury.

Dec. 22, 2015
References
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  2. Frontera WR. Anterior cruciate ligament tear. In: Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. 3rd ed. Philadelphia, Pa.: Saunders Elsevier; 2015. http://www.clinicalkey.com. Accessed Oct. 22, 2015.
  3. Anterior cruciate ligament (ACL) injuries. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=a00549. Accessed Oct. 15, 2015.
  4. ACL injury: Does it require surgery? American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00297. Accessed Oct. 15, 2015.
  5. Shea KG, et al. The American Academy of Orthopaedic Surgeons evidence-based guideline on management of anterior cruciate ligament injuries. Journal of Bone and Joint Surgery. 2015;97:672.
  6. Knee arthroscopy exercise guide. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00300. Accessed Oct. 15. 2015.
  7. Stuart MJ (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 28, 2015.
  8. Peterson JR, et al. Anterior cruciate ligament injury: Mechanisms of injury and strategies for injury prevention. Physical Medicine and Rehabilitation Clinics of North America. 2014;25:813.
  9. ACL injuries in young athletes. Stop Sport Injuries. American Orthopaedic Society for Sports Medicine. http://www.stopsportsinjuries.org/acl-injury-prevention.aspx. Accessed Nov. 24, 2015.