Methods of ACL Reconstruction

Completely torn ACLs almost never heal on their own, and unlike tears in some other knee ligaments, cannot be stitched back together very effectively. The injured ACL must almost always be surgically rebuilt, or "reconstructed", using a replacement ligament (tendon autograft or allograft). Autograft tissue is harvested from the patient's own body whereas allograft tissue is obtained from a tissue bank. Many orthopedic surgeons who perform ACL reconstruction have one preferred surgical method or technique, which they learned during their surgical training, and thus feel most comfortable with. They therefore use this method in the great majority of their cases, regardless of the patient's age, sex, activity level or occupation. This is not the approach that we take at The Knee and Shoulder Centers. We feel comfortable performing all of the commonly used methods of anterior cruciate ligament reconstruction and use a variety of different tendon grafts as an ACL replacement. Each person with a torn ACL represents a unique situation that calls for surgical decision-making customized to the particular context of that patient's case.

For example, a time-tested and very commonly performed method of ACL reconstruction that utilizes an implanted ligament graft composed of the middle third of the patient's own patellar tendon (see FIGURES 7a, 7b) typically provides excellent restoration of knee stability 90 or more percent of the time, but is sometimes a difficult procedure to recover from.

FIGURE 7a - This photo demonstrates the patellar tendon autograft method of ACL reconstruction, whereby the middle 1/3 of this frontal knee tendon, with a bone plug at either end, is first excised and then re-implanted inside the knee where the ACL originally was. The defects in the patellar tendon, patella and tibia left from the graft "harvesting" procedure gradually fill in with scar and repair tissue.

FIGURE 7b - Diagrammatic illustration of how a patellar tendon graft is surgically implanted into the knee where the original ACL was located. Two screws hold the (bone plug) ends of the new ACL in place.

In our experience, this surgical method poses a higher risk for unwanted side-effects such as patellar tendinitis, patellar pain, joint stiffness, internal scarring, and an inability to kneel on firm surfaces (any or all of which could be permanent). For this reason, we view this particular procedure as being more ideally suited to younger (under 25), high-demand athletes who are not likely to be called upon to kneel on hard surfaces in an occupational setting. Patellar tendon autograft ACL reconstruction, done in the wrong patient, has a significant chance of leading to an unhappy result. We are of the opinion that an individual over 25 with an acute (recent) anterior cruciate ligament injury that has not yet resulted in a highly unstable joint, and who later may be required to do more kneeling activity in an occupational setting than cutting or pivoting in an athletic environment, is better suited for other methods of anterior cruciate ligament reconstruction. These alternate methods utilize either two of the patient's own accessory hamstring tendons (semitendinosus and gracilis) as an ACL graft (see FIGURE 8), a part of the patient's own quadriceps tendon from the front of the lower thigh, or an allograft tendon specimen obtained from a tissue bank (see FIGURE 9).

FIGURE 8 - This photo demonstrates how two accessory (thus relatively expendable) hamstring tendons can be retrieved from the thigh through a 1½ inch long incision, made just below the knee. These tendons are then doubled or tripled-over, and fashioned into an ACL graft that is arthroscopically implanted into the knee at the site where the original ACL was located.

FIGURE 9 - Photo demonstrating an "allograft" bone/patellar-tendon/bone specimen that has been obtained from a certified tissue bank. The photo shows the specimen after it has been cut down to size and fashioned into a new ACL. The white, middle section becomes the new ligament and the bone plugs at either end serve as anchors that become imbedded in the femur and tibia.

These alternate techniques leave the patient's own patellar tendon untouched and rarely produce sensitive areas in the front of the knee to be bothered later on by floor contact when kneeling. While there is no surgical knee procedure that poses zero risk of an unhappy or frankly failed outcome, these alternate methods are often better tolerated by many patients as compared with ACL reconstruction using their own patellar tendon.

There are also various specific technical advantages and disadvantages to each particular surgical method and/or ACL graft when considered in the context of a patient's exact clinical circumstances. Taking into account these various details, educating the patient about them and then jointly arriving at a decision as to how to proceed, is our preferred approach to the problem of the ruptured anterior cruciate ligament. Our goal is to subject a patient's knee to no more surgical stress than is necessary to achieve the desired result.