ACL Repair Techniques

Anterior cruciate ligament or ACL injuries are one of the most common sports injuries seen by orthopedic surgeons. The ACL is the tendon that runs through the middle of the knee and gives the knee stability and range of motion. The goal of these different ACL repair techniques is to put that stability and range of motion back into the injured knee. All of these techniques use grafts that can either be taken from the patient (autograft) or from a cadaver (allograft).

Patella Tendon Graft

• The patella tendon graft technique involves taking a piece of tendon from below the patient's kneecap and grafting it into the knee to replace the torn ACL. The new graft has bone plugs attached on each end. The graft is aligned into the knee in the exact location of the original tendon. This surgery is performed with an arthroscope so the surgeon does not have to open the entire knee. This method is considered the strongest of the ACL repair techniques.

Hamstring Graft

• The hamstring graft involves using a medial hamstring such as the semitendonosis or semimembranosis. The semimembranosis is more commonly used because it is easier to insert. The tendon is stripped and removed using an anterior-medial incision. The surgeon folds the tendon over itself, which results in a four-layer graft. The graft is held in place using hardware such as screws. The benefits of this surgery are that there is less knee pain, range of motion returns quicker and there is no injury to the extensor mechanism of the knee. Because this ACL repair technique does not involve bone to bone healing, some consider it not as strong as a patella tendon graft, and recovery depends on hardware to keep the knee in perfect position. Recovery times can be longer with this technique.

Double-Bundle Technique

• The double-bundle technique uses hamstring or quadriceps tendons to graft to the knee to repair the torn ACL back to its original state as closely as possible. Surgeons refer to this as an anatomic reconstruction. With this technique, both ACL tendon insertion sites are marked on the tibia and femur. The insertion sites for both tendon bundles are measured to decide how to size the graft for that patient. Four tunnels are created to insert the grafts. The grafts are fastened with either screws, special fasteners or staples. This repair technique also uses a "fibrin clot" to promote faster healing after surgery. The fibrin clot is made from the patient's own blood, which is removed, put into a beaker and stirred to create the process of "hemostasis." This process changes the blood from a liquid to a solid state. The clot is then inserted between the tendon bundles. Range of motion after this repair is typically excellent and close to the range of motion of the healthy knee within one to three months post surgery.