Clinical and Biomechanical Outcomes of Anterior Cruciate Ligament (ACL) Reconstruction Associated With Lateral Extra-articular Tenodesis (LET)

The anterior cruciate ligament (ACL) is one of the main stabilizers of the knee joint, and its injury is among the most common soft tissue injuries of the knee. Several surgical reconstruction techniques are available, utilizing various tissues as a graft for the neo-ligament, including both autografts and allografts. The "Over-the-top single-bundle technique with gracilis and semitendinosus tendons combined with lateral extra-articular tenodesis (LET)" was developed in 1998 by Prof. Marcacci and Prof. Zaffagnini, and it is still the preferred method for ACL reconstruction at the Second Clinic of the Rizzoli Orthopaedic Institute. Cadaveric biomechanical studies have shown that combining LET with ACL reconstruction improves knee joint stability in both the anteroposterior and rotational planes. However, a recent in vivo study has challenged this hypothesis, showing that in patients undergoing surgery, the addition of LET enhances knee stability only in the anteroposterior direction and only for a limited period of six months. At twelve months postoperatively, joint laxity appeared similar to that of patients who did not undergo the additional procedure. Furthermore, the same study did not assess rotational instability using the pivot-shift test, an essential parameter as it is closely linked to knee stability and the patient's subjective perception of surgical success. Despite the increasing use of LET in conjunction with ACL reconstruction, few studies have analyzed the short-term postoperative effects of lateral extra-articular tenodesis and its potential benefits during the early stages of rehabilitation and return to sport. This study was conceived in response to this clinical question, with the goal of evaluating anteroposterior and rotational laxity in a group of patients who underwent ACL reconstruction combined with LET, in order to analyze clinical outcomes and, most importantly, any changes in stability during the early postoperative period. The results aim to improve understanding of knee stability in the initial phase following surgery, providing valuable information for rehabilitation teams to optimize recovery protocols and more effectively guide return-to-sport decisions for patients undergoing both procedures.