The anterior cruciate ligament, or ACL, helps guide the shin bone through a normal range of motion, according to the Stone Clinic. Tearing of the ACL renders the joint unstable, and repair is necessary. The ACL can be repaired surgically and in many cases, the surgery is successful. In some people, a second surgery may need to be performed; this is known as ACL revision surgery.
Siginificance
ACL injuries occur in approximately one out of every 3,000 people, according to the Southern California Orthopedic Institute. The Institute also estimates that more than 100,000 ACL reconstructions are performed yearly, with a success rate of approximately 80 to 90 percent. Of the unsuccessful ACL repairs, 8 percent are likely caused by knee instability or a re-tearing of the graft of the ACL, says the Institute.
Causes
The Stone Clinic lists several reasons for needing ACL revision surgery, including: improper placement of drill holes, leading to stresses on the graft; graft fixation failure or impingement; intrinsic failure of the graft; arthofibrosis, or formation of scar tissue; and trauma. Injuries to other parts of the knee or leg alignment can also affect the initial ACL repair, says the Southern California Orthopedic Institute. The Institute also notes that the timing of the failure can suggest the cause; failures less than six months post-surgery are likely due to either poor surgical technique, failure of the graft to heal or rehabilitation that is too aggressive. Those failures that occur after one year post-surgery are typically due to other causes, such as trauma.
Features
ACL revision often requires more than one surgery, according to Dr. Walter Lowe, an orthopedic sports medicine surgeon. The first surgery involves removing the screws from the original tunnels that were drilled to attach the ligaments, repairing further damage that may have occurred, and grafting the tunnels with donor bone plugs. After healing of the bone grafts, the second surgery is done; this is when new holes are drilled and the actual reconstruction of the ACL takes place.
Rehabilitation
Physical rehabilitation following an ACL revision surgery can take longer and is less aggressive than rehabilitation after an initial ACL repair, according to the Southern California Orthopedic Institute. Physical therapy is often staged, so as not to stress the knee too soon. ACL revision surgeries can yield less-predictable results than first ACL surgeries, so it is important to protect the reconstructed knee to allow it to heal. Therapy programs are usually tailored to the specific type of graft used and the type of surgeries performed.
Considerations
ACL revision surgery is a major procedure with a significant rehabilitation period, and should be carefully considered. The reasons for the failure of the first reconstruction need to be identified and planning of the subsequent revisions is crucial. As the Southern California Orthopedic Institute warns, the results of the ACL revision are not going to be as good as the initial ACL repair, and the main goal is not to return to sports, but to enable the patient to perform daily activities.
