Anterior Cruciate Ligament Injury

GENERAL INFORMATION:

What is an anterior cruciate ligament injury? An anterior cruciate (KROO-she-at) ligament (ACL) injury is a partial or complete tear of the ACL. A ligament is a strong elastic tissue that connects one bone to another. The ACL is located in the knee and connects the tibia (shin bone) to the femur (thigh bone). It stops the tibia from sliding too far forward and keeps the knee stable. When the ACL is injured, other ligaments of the knee may also be affected. One or more of the menisci (cartilage shock absorbers between knee bones) may also be damaged. Injury to the ACL may cause the ligament to pull off a part of the shin bone.

What causes an anterior cruciate ligament injury?

• Car accidents and falls: Car accidents or falls may lead to an ACL injury.
  
  
• Contact sports: A contact ACL injury may occur when the outer or inner side of the knee gets hit hard. This is often seen in contact sports, such as football, basketball, and hockey.
  
  
• Other causes: An ACL injury may also be caused by the following:
  
  
  • Forcefully twisting the knee while standing firmly in place.
    
    
  • Overextending the knee too much.
    
    
  • Suddenly stopping or changing direction while running.

• Physical exam: Caregivers may test the function of your ACL by moving your knee, leg, or foot in different directions. You may be asked to lean or hop using your leg with the injured knee. An ACL injury may be suspected if these activities are painful. Both your injured and normal knee may need to be checked for any abnormal movement.
  
  
• X-ray: This is a picture of the bones and tissues in your knee joint. A joint is where two bones meet. X-rays cannot show an ACL injury but may show other problems, such as fractures (broken bones) or arthritis. You may be given dye as a shot into your joint before the x-ray. This dye will help your joint show up better on the x-ray. A joint x-ray with dye is called an arthrogram or arthrography. You may need more than one x-ray of your joint.
  
  
• Magnetic resonance imaging: This is also called MRI. During the MRI, pictures of your knee are taken. An MRI may be used to look for ACL tears or other injuries.
  
  
• Arthroscopy: Caregivers may want to look inside your knee to check for signs of an ACL injury. Caregivers make a small incision (cut) in your knee and insert a scope through it. The scope is a long tube with a magnifying glass, a camera, and a light on the end.

• Devices: You may need to wear a knee brace to keep your knee stable. You may need to use crutches to decrease stress and strain on your knee.
  
  
• Medicine: Your caregiver may give you certain medicines to decrease the pain and swelling of your knee joint.
  
  
• Surgery:
  
  
  • Repair: An ACL tear may be repaired by reattaching the torn ligament.
    
    
  • Reconstruction: Reconstruction (rebuilding) of the ligament may be needed if it cannot be repaired. Caregivers may replace your injured ACL with tissue taken from another part of your body or from a donor. A tendon (cord that connects muscles to the bones) or a muscle may be used. If a large portion of bone is pulled off with the torn ligament, it may be reattached.
  
  
• Rehabilitation: This is an exercise program that helps keep your knee stable after having an ACL injury. This program aims to bring back your knee's normal range of motion and strengthen the thigh muscles. You may be asked to do exercises, such as stair climbing or squats.

• American Academy of Family Physicians
  PO Box 11210
  Shawnee Mission, KS 66207-1210
  Phone: 1-913-906-6000
  Web Address: http://www.aafp.org
  

• American Academy of Orthopaedic Surgeons
  6300 North River Road
  Rosemont, IL 600184262
  Phone: 1-847-8237186
  Web Address: http://www.aaos.org/
  

• American Physical Therapy Association
  1111 North Fairfax Street
  Alexandria, VA 22314
  Phone: 1-800-999-2782
  Web Address: http://www.apta.org