ACL reconstruction is a surgical procedure that repairs a torn anterior cruciate ligament (ACL), one of the four ligaments that help stabilize the knee. The ligament is reconstructed using a tendon that is passed through the inside of the knee joint and secured to the upper leg bone (femur) and one of the two lower leg bones (tibia).

The tendon used for reconstruction is called a graft and can come from different sources. It is usually taken from the patient’s own patella, hamstring, or quadriceps, or it can come from a cadaver. ACL reconstruction is most often performed through arthroscopic surgery.