Rebranding the ‘anatomic’ ACL reconstruction: Current concepts

Abstract

The anterior cruciate ligament (ACL) is a complex ribbon-like structure, which is approximately 3.5 times larger at the tibial and femoral insertions than at the midpoint. Accordingly, it is impossible to recreate with a single cylindrical graft. However, this has not stopped surgeons from using the term “anatomic” to describe multiple ACL reconstruction techniques inserting at a number of different locations within the original ACL footprint, causing confusion. The term “anatomic” should be discarded and replaced by an anatomic description of the tunnel placements on the tibia and femur. Current ACL reconstruction techniques cite anatomical studies that identified “direct and indirect fibres” of the ACL. The “direct fibres” bear 85–95% of the load and provide the main resistance to both anterior tibial translation and internal rotation/pivot shift. On the femur, these fibres insert in a line just posterior to the intercondylar ridge and comprise the portion of the ACL that surgeons should strive to restore. Placement of the graft just posterior to the intercondylar ridge creates a line of placement options from the anteromedial bundle to the “central” position and finally to the posterolateral bundle position. The authors prefer placing the femoral tunnel in the isometric anteromedial position and addressing a high-grade pivot shift at the IT-band with a lateral extra-articular tenodesis. As with the femoral tunnel, the native ACL footprint on the tibia is much larger than the ACL graft and thus can be placed in multiple “anatomic” locations. The authors prefer placement of the tibial tunnel in the anterior most position of the native footprint that does not cause impingement in the femoral notch. Additional research is needed to determine the ideal tunnel positions on the femur and tibia and validating the technique with patient outcomes. However, this cannot be accomplished without describing tunnel placement with specific anatomical locations so other surgeons can replicate the technique.