The anterior cruciate ligament (ACL) is a ligament in the center of the knee that prevents the shin bone (tibia) from moving forward on the thigh bone (femur).

If the ACL is torn, the knee joint may become unstable and affect the ability to perform work or athletic activities.

ACL reconstruction is surgery to replace the torn ACL ligament. There are several choices of tissue to use for the new ligament, including an autograft (tissue from the patient's own body) or an allograft (tissue from a cadaver). One of the most common autografts use part of the patellar tendon (the tendon in the front of the knee).

The old ligament is removed using a shaver or other instruments. Bone tunnels are made to place the new ligament (patellar graft) in the knee at the site of the old ACL. Screws are commonly used to secure the graft in the bone tunnels, although other methods of fixation are used depending on the type of graft used.

At the end of the surgery, the incisions are closed, and a dressing is applied. ACL reconstruction is usually a very successful surgery. The majority of patients will have a stable knee that does not give way after ACL reconstruction.