The Anterior Cruciate Ligament (ACL) plays a vital role in maintaining function and stability in the knee. Over the last several decades, much research has been focused on elucidating the anatomy, structural properties, biomechanics, pathology, and optimal treatments for the ACL. Through careful and objective study, the ACL can be understood to be a dynamic structure, rich in neurovascular supply. Although it is referred to as one ligament, it is comprised of two dis-tinct bundles which function synergistically to facilitate normal knee kinematics. The bony morphology of the knee defines normal knee kinematics, as well as the nature of the soft-tissue structures about the knee. Characterized by individual uniqueness, bony morphology varies from patient to patient. The ACL, which is a reflection of each patient's unique bony morphol-ogy, is inherently subject to both anatomic and morphologic variation as well. Furthermore, the ACL is subject to physiologic aging, which can affect the anatomic and structural properties of the ligament over time. A successful anatomic ACL Reconstruction, which may be considered the functional restoration of the ACL to its native dimensions, collagen orientation, and inser-tion sites according to individual anatomy, considers all these principles. It is vital to respect the nature we observe, rather than to “create” nature to fit a one-size-fits-all surgery. Double bundle ACL Reconstruction may therefore be thought of more as a concept rather than a specific technique, one that respects the individual unique anatomy of each patient to provide a truly indi-vidualized, anatomic, and value-based ACL Reconstruction

Background:. The Lateral Intercondylar Ridge (LIR) gained notoriety with arthroscopic trans-tibial Anterior Cruciate Ligament (ACL) reconstruction where it was mistakenly used to position the ‘over the top’ guide resulting in graft malposition. With anatomic ACL reconstruction some surgeons use the same ridge to define the anterior margin of the ACL femoral insertion in order to guide graft placement. However there is debate about whether this ridge is a consistent and reliable anatomical structure. The aim of our study was to identify whether the LIR is a consistent anatomical structure and to define its relationship with the femoral ACL insertion. Methods:. In the first part, we studied 23 dry bone specimens. Using a digital microscribe, we created a 3D model of the medial surface of the lateral femoral condyle to evaluate whether there was an identifiable bony ridge. In the second part, we studied 7 cadaveric specimens with soft tissues intact. The soft tissues were dissected to identify the femoral ACL insertion. A 3D reconstruction of the femoral insertion and the surface allowed us to define the relationship between the LIR and the ACL insertion. Results:. All specimens (23 dry bones; 7 intact soft tissues) had a defined ridge on the medial surface of the lateral femoral condyle. The ridge extends from the apex point of the lateral intercondylar notch, where the posterior condyle meets the femoral shaft, and extends obliquely to the articular margin. The mean distance from the midpoint of the posterior condylar articular margin was 10.1 mm. The ridge was consistently located just anterior to the femoral ACL insertion. Conclusion:. This study shows that the LIR is a consistent anatomical structure that defines the anterior margin of the femoral ACL insertion. This supports its use as a landmark for femoral tunnel placement in ACL reconstruction surgery. Abstract 28