A Patient's Guide to Graft Selection in Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) injuries are one of the most common injuries in orthopaedics. ACL injury can be treated either surgically or non-surgically. When surgery is performed, the torn ligament is replaced with a new tissue that will turn into ligament over time. The two main options are autograft, which means that the tissue used to reconstruct the ACL comes from you, and allograft, which means that the tissue used comes from a donor/cadaver. There are several different autograft and allograft options available to patients for ACL reconstruction and these will be discussed below. Background Information The ACL is an important stabilizer of the knee and its main function is to prevent the tibia (shin bone) from moving forward relative to the femur (thigh bone). Nearly 75% of ACL injuries are the result of a non-contact mechanism and are usually due to a change in speed and direction. This position can be visualized in a basketball player sprinting and pulling up for a jump shot or a football player planting and changing direction to avoid a defender. During these types of movements increased strain is placed upon the knee and can cause the ACL to tear. ACL injuries represent one of the most common injuries in orthopaedics with about 200,000 occurring per year. Further, females sustain ACL injury at a rate of 2-8 times that of males. With increasing rates of participation in sports, it is expected that the amount of ACL injuries will continue to rise in coming years. Therefore, ACL reconstruction surgery is one of the most common procedures performed by both general and sports orthopaedic surgeons. The sports that are most often associated with ACL injuries include skiing, basketball and soccer. Treatment of ACL Injury Tears of the ACL can be managed either non-surgically or surgically. The decision on treatment route is usually based on patient age, activity level, and symptoms. Most physicians agree that patients with high physical demands or those whose injury interferes with daily living are good candidates for surgery. The non-surgical option is a rehabilitation program focused on strengthening the muscles of the leg to help the knee feel more stable. A reasonable alternative for patients who are unsure about surgical treatment is a combined approach of physical therapy followed by reassessment. In this option the patient begins a therapy program and is later re-examined to determine if they are still having symptoms of knee instability. Those who are still symptomatic can then undergo ACL reconstruction. This option has been found to be equally as effective as immediate ACL reconstruction and roughly 50% of these patients do not end up needing surgery. In those with persistent instability of their knee, the goal of ACL reconstruction is to restore the knee’s stability and prevent development of early osteoarthritis, though having ACL surgery has not been shown to prevent arthritis. This approach is not recommended in younger patients, as delays in surgery after tearing the ACL have been shown to lead to more injuries of the cartilage and meniscus. Surgery to reconstruct the ACL is done arthroscopically, which means that it is done with the use of a camera through small incisions made in the knee. In reconstructive ACL surgery the patient’s damaged ACL is completely removed and replaced using either tissue from you (autograft) or donor tissue (allograft) from a cadaver. In the case of using autograft tissue, two procedures are performed during the surgery. The first is a “harvest” procedure, which involves the removal of tissue from another area around the knee that will be used as the graft. The second procedure is arthroscopic reconstruction, which involves placing this new graft tissue in the location of the previous ACL. In the case of using allograft tissue only the later procedure is performed since the graft is already available.