Why it's done

The ACL — one of two ligaments that crosses the middle of the knee — connects your thighbone to your shinbone and helps stabilize your knee joint.

Most ACL injuries happen during sports and fitness activities that can put stress on the knee:

• Suddenly slowing down and changing direction (cutting)
• Pivoting with your foot firmly planted
• Landing from a jump incorrectly
• Stopping suddenly
• Receiving a direct blow to the knee

A course of physical therapy may successfully treat an ACL injury for people who are relatively inactive, engage in moderate exercise and recreational activities, or play sports that put less stress on the knees.

ACL reconstruction is generally recommended if:

• You're an athlete and want to continue in your sport, especially if the sport involves jumping, cutting or pivoting
• More than one ligament is injured
• You have a torn meniscus that requires repair
• The injury is causing your knee to buckle during everyday activities
• You're young (though other factors, such as activity level and knee instability, are more important than age)