Normal Anatomy and Function of ACL: The anterior cruciate ligament (ACL) attaches the tibia (shin bone) to the femur (upper leg bone) at the middle of the knee. The function of this ligament that connects bone to bone is to provides strength and balance to the joint. Measuring about the size of a finger, the ACL is a large, dense cord that can take up to 250 kgs of pressure before it will tear. The ACL's vital function of directing the tibia in its correct path from the end of the femur maintains joint stability. If the ACL tears or ruptures, bleeding will occur and the knee will become unstable. Behind the ACL lies a similar ligamentous structure posterior cruciate ligament (PCL) which manages the backward movement of the tibia. Working with the muscles in the leg, the ACL and PCL control the amount of stress put on our knee when using it to walk, run or jump.
ACL Tear: An ACL tear usually occurs when a person sustains either a slow, twisting fall or the knee is unexpectedly extended or flexed. The activities that causes a majority of ACL tears and knee injuries are football, rugby, cricket. Sometimes it may also occur following low intensity trivial trauma, this happens usually at advanced age secondary to degenerative changes. It is the most common ligament that gets injured in the knee. The other common structure that gets injured is medial meniscus.
Symptoms of the ACL tear: The tear common follows an injury during which a pop sound could be felt in the knee joint, this is usually followed by a swelling in the knee joint that appears usually within an hour of this injury. Later on a recurrent sense of giving away may occur. This may especially be apparent when you take a sharp turn while walking fast or while climbing up and down the stairs.
Diagnostic Tests: Usually the doctors can diagnose the condition clinically, but he may also take radiograph, MRI, if needed. Occasionally a diagnostic arthroscopy may be needed. This is a minimally invasive procedure in which the operating surgeon passes a tube containing a lens system connected to a camera to visualize the knee joint.
Treatment: The treatment is usually operative except in certain cases where tear is partial. Non-surgical treatments of ACL tears consist of physical therapy, a change in activities, and the use of a brace. Physical therapy strengthens the muscles around the knee to make up for the loss of an ACL.
Surgery is necessary to restore stability to the knee and at the same time protect the cartilage in the knee from becoming damaged. If let un treated for long period, it may result in development of arthritis. There are several surgical options for reconstructing the ACL. ACL can be reconstructed from a graft taken from a part of your own patellar tendon or through a graft taken from Hamstring. Some surgeons also prefer using graft from another persons body or a cadaver (Allograft) or use one of the currently available synthetic material.
To perform the procedure, the surgeon commonly uses arthroscopic-assisted techniques. One or two incisions are made in the knee and a tunnel is drilled into both the tibia and the femur. The graft is brought in through these tunnels and secured by either staples, screws, sutures or buttons. Accurate placement (Isometric placement) is the key to successful surgery.
Rehabilitation after Surgery: After surgery, physiotherapy of the knee will be necessary. Immediately following surgery, most patients will be made to walk non weight bearing on crutches for 5 to 10 days. Physical therapy can then be started to help you regain flexibility and motion of the knee. You may be put on machine that helps you recover your knee flexion (continuous passive motion).
Return to Normal activity: You can start going to work in two to three weeks depending on how your surgery went. After 5 to 12 months, 90 percent of patients are able to return to normal activities including sporting activities. Pain, swelling or other unidentified causes prevent the other 10 percent from a full return to their level of activity prior to the injury.
