A New Algorithm for Extra-Articular Reinforcement in ACL Injury Based on Rotational Instability

The results of surgical reconstructions of the anterior cruciate ligament (ACL) are improving with the association of extra-articular reinforcements, such as anterolateral ligament reconstruction and Lemaire tenodesis. However, ACL injury can occur through various mechanisms, and when there are valgus and external rotation of the tibia, anteromedial rotational instability (AMRI) may develop. Articular reinforcement in the anteromedial quadrant, in the topography of the anterior oblique ligament (AOL), can be an important tool for patients with ACL injury and external rotation instability.

The physical examination under anesthesia in patients undergoing ACL reconstruction who are candidates for extra-articular reinforcements provides important information about rotational instability. Patients with instability in external rotation may benefit from anteromedial reinforcement in the AOL's topography.

We propose an algorithm to be followed in patients with ACL injury and indication for extra-articular reinforcement. Patients with a positive pivot shift, indicating internal rotation instability of the knee, should undergo anterolateral reinforcements, as well as those patients with joint hyperlaxity. The algorithm suggests performing the anterior drawer in external rotation (ADER) test. When positive in isolation, anteromedial reinforcement is indicated. When the physical examination shows both positive ADER and pivot shift, both medial and lateral extra-articular reinforcement could be performed.

This new type of extra-articular reinforcement, in the AOL's topography, appears to be an important tool for improving surgical outcomes in ACL reconstructions. AMRI is a risk factor for central pivot reconstruction failure and should be investigated and treated, as proposed by the algorithm.

Clinical examination of the ACL-injured knee, preferably under anesthesia, should include internal rotational and external rotational examination (pivot-shift and ADER tests). AMRI, when detected, should be treated, and the AOL reconstruction seems to be a good alternative. We propose a new algorithm based on rotational instability to make our extra-articular reinforcement in ACL patients.

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