The anterior cruciate ligament, or ACL, is located in the center of the knee along with the posterior cruciate ligament, or PCL. These ligaments wrap tightly around the femur and the tibia of the leg to form a crisscross pattern in the knee, which prevents the joint from moving too far forward or backward. Injuries to the ACL are usually sports related. However a torn, stretched, or ruptured ACL can also be caused by repetitive physical stress, such as excessive pivoting or twisting of the knee. Arthroscopic surgery can be used to replace the torn ligament. During this procedure, an arthroscopic shaver is used to remove the remains of the torn ligament. A hole is then drilled from the front of the tibia into the knee joint where the ACL would attach. A second hole is drilled in the femur running up from the joint to the outside. Next, the replacement tissue, or graft, may be taken from the patellar ligament. The middle 1/3 of the ligament along with attached pieces of the patella and tibia, called bone blocks, are removed. The graft is pulled through the two tunnels that were drilled in the tibia and femur. It is then secured into place using screws. Arthroscopic ACL repair surgery is usually done on an outpatient basis. Physical rehabilitation is necessary and a full return to sports activities can vary and may take up to 6 months after surgery. There can be complications from ACL repair surgery, therefore always discuss with your doctor which treatment option is best for you.