Anterior cruciate ligament anatomy and function relating to anatomical reconstruction

Abstract

Recently, the interest in surgical techniques that reconstruct the anteromedial (AM) and the posterolateral (PL) bundles of the anterior cruciate ligament (ACL) has risen. This review focuses on the structural as well as the mechanical properties of the ACL and the anatomical details of the femoral origin, midsubstance, and tibial insertion of AM and PL bundles of the ACL. The terminology of AM and PL bundles is chosen according to the tibial insertion and determined by their functional tensioning pattern throughout knee flexion. Close to extension the AM is moderately loose and the PL is tight. As the knee is flexed, the femoral attachment of the ACL becomes more horizontally oriented, causing the AM bundle to tighten and the PM bundle to loosen up. The ACL has been described to be restraint to anterior tibial displacement and internal tibial rotation. The rotational component might be represented by the PL bundle. The femoral origin has an oval shape with the center of the AM close to over-the-top position and the center of the PL close to the anterior and inferior cartilage margin. Tibial and femoral insertions of the ACL are over 3.5 times larger when compared to the midsubstance and tunnel placement is more challenging because of the limited size of potential grafts selection of tunnel site placement. For reconstruction, both bone-patellar tendon-bone (BPTB) and quadrupled hamstring grafts are used. Structural properties of a 10 mm wide BPTB or quadrupled hamstring graft have been reported to be comparable with those of the native ACL.

A prospective study to evaluate the clinico-radiological outcomes of arthroscopic single bundle versus double bundle anterior cruciate ligament reconstruction

“…16,17 Recently, double bundle ACL has gained in popularity where each bundle of the ACL is reconstructed separately with correct tensioning pattern of each bundle. The AM bundle is taut throughout the knee range of motion, reaching a maximum of between 458 and 608, whereas the PL bundle is tight primarily in extension.…”

“…The AM bundle is taut throughout the knee range of motion, reaching a maximum of between 458 and 608, whereas the PL bundle is tight primarily in extension. 16 Therefore, the AM and PL bundles are fixated accordingly, to restore their native tensioning behaviors. An in vivo kinematics study has shown that conventional singlebundle ACL reconstruction, which most closely imitates AM bundle reconstruction, can successfully restore anterior knee stability but does not sufficiently bring back rotational stability.…”

MRI depiction and 3D visualization of three anterior cruciate ligament bundles

“…The functional anatomy of the normal ACL fiber bundles has drawn interest (Zantop et al, 2006;Siebold et al, 2008). Detailed knowledge of the bundle anatomy of the ACL is of great clinical value, particularly in ACL reconstruction surgery.…”

“…The goal of ACL reconstruction is not only to obtain the knee stability without loss of motion, but also to restore the same kinematics as the native knee. Therefore, more anatomical reconstructions in which tendon grafts were placed at original attachment sites of each fiber bundle to mimic the native anatomy as closely as possible, were developed (Odensten and Gillquist, 1985;Muneta et al, 1999;Shino et al, 2005;Zantop et al, 2006;Otsubo et al, 2007;Siebold et al, 2008). Actually, the multiple bundle ACL reconstruction such as double bundle reconstruction has been increasingly popular in the clinical settings (Muneta et al, 1999;Otsubo et al, 2007).…”

Anatomic Anterior Cruciate Ligament Reconstruction: The Use of the Anterior Horn of the Lateral Meniscus as a Guide to Tibial Tunnel Placement

“…1 Accurate, anatomic ACL graft position re-creates the normal anatomy and improves stability, both rotational and anteroposterior stability, of a patient's knee joint. 2 Tunnel malposition is a technical error that has been shown to significantly increase the rate of graft failure and poor functional outcomes.…”