The anterior cruciate ligament (ACL) is one of four main ligaments in the knee joint, which help connect one bone firmly to another. The ACL is located in the center of the knee joint, connecting the bottom surface of the thigh bone (femur) to the top surface of the shin bone (tibia) as they face each other in the joint.
The job of the ACL is to stabilize the knee joint during motions that twist and slide the knee forward. An injury of the ACL is among the most common injuries in active sports. This injury can occur when the knee is hit from the outside while the foot is planted, when the knee is twisted and the ACL is stretched beyond its normal position, and when the end of the thigh bone (femur) slides quickly over the top surface of the tibia (shin bone) (such as when coming to a sudden stop while running).
Because this ligament will not heal on its own, a torn or "ruptured" ACL must be surgically repaired. To reconstruct the ACL, pieces of ligaments or tendons from other areas of the body are used to replace the original tissue. Tissue that is borrowed from other areas of the body to replace torn tissue is called a "graft".
The most common place from which a graft is taken for ACL reconstruction is the patellar tendon. This tendon provides a strong attachment from the patella (kneecap) to the shinbone. A small section in the center of the wide tendon is removed, along with the small bone pieces on either end that are used to attach the ligament to the bone. Grafts can also come from the hamstring tendon (on the back side of your thigh).
Your doctor will give you anesthesia to completely numb the area of your knee. Spinal anesthesias numb the area from your waist down and allow you to remain awake during the procedure. General anesthesia helps you go into a deep sleep during the entire surgery.
After the anesthesia has taken effect, the doctor will prepare the graft of tissue, most commonly from your patellar tendon. If this tendon is chosen as the graft, an incision will be made below your kneecap to remove the graft. Arthroscopy is then used to remove the torn ACL. In this part of the procedure, your doctor will use an arthroscope to view the inside of your knee joint. An arthroscope is a thin tube and tiny camera through which your doctor can view the inside of your knee joint. Using a tiny drill, small holes will be made in the bottom surface of your femur (thigh bone) and the top surface of the tibia (shin bone) in order to attach the graft. The graft is anchored in these holes by screws or staples. Following the procedure, the incisions will be closed with stitches or tape.
It is important to understand the risks associated with general anesthesia. Be sure to talk with your doctor about the different anesthesia choices and the risks involved with each. Other risks include stiffening of the knee joint, continued pain in the knee, excessive bleeding at the area of surgery, clotting of blood in the legs, and the rare possibility of nerve or artery damage in the area of incision, which can cause tingling and weakness in the leg. Talk with your doctor about the risks associated with this surgical procedure and how they apply to you.
The time for recovery from ACL surgery depends on the injury or condition and the extent of the surgery.
Rest, elevation of the knee, the use of ice packs, and anti-inflammatory medications may be recommended to help reduce swelling and pain after surgery. Crutches may be used for a couple of weeks to ease pressure on your knee. Driving may be difficult for the first few weeks after surgery, particularly with right leg surgery and cars with manual shifting.
You may also be referred for an exercise program prescribed by a physical therapist to help with your rehabilitation. It is normally suggested that patients avoid heavy athletic activities for four to twelve months in order to give the tissues time to heal and strengthen properly. Talk with your doctor and physical therapist about the best rehabilitation program for your injury.