CausesBy Mayo Clinic staff
CLICK TO ENLARGE
Ligaments are strong bands of tissue that connect one bone to another. The ACL, one of two ligaments that cross in the middle of the knee, connects your thighbone (femur) to your shinbone (tibia) and helps stabilize your knee joint.
Most ACL injuries happen during sports and fitness activities. The ligament may tear when you slow down suddenly to change direction or pivot with your foot firmly planted, twisting or hyperextending your knee.
Landing awkwardly from a jump can also injure your ACL, as can falls during downhill skiing. A football tackle or motor vehicle accident also can cause an ACL injury. However, most ACL injuries occur without such contact.
- Frontera WR, et al. Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/208746819-6/0/1678/0.html. Accessed Oct. 25, 2012.
- 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.