What is the ACL?

What is the Anterior Cruciate Ligament? 

The Anterior Cruciate Ligament (ACL) is a ligament deep inside the knee (meaning you can't touch it from the outside). It helps stabilize the tibia on the femur above it. 

When the ACL is torn, the tibia is more likely to translate anteriorly, or forward. This can cause further damage in the knee, such as a meniscus tear, if it didn't occur during the initial injury itself. People with torn ACL's often describe a feeling of instability or giving out in the knee. There is usually quite a bit of swelling at the time of injury. 

Surgery is not always required after an ACL tear. Many people are able to cope with the injury if they maintain strength in the muscles surrounding the knee. I ran a marathon with a torn ACL and meniscus, though it was painful! I did eventually get it reconstructed the following year when it became more unstable. 


-- Korey Pieper, DPT, OCS