Intra-articular landmarks for anterior cruciate ligament reconstructions: a review

The anterior cruciate ligament (ACL) is one of the most important stabilizers of the knee joint. It resists anterior tibial translation and serves as a secondary restraint to internal tibial rotation [1–3]. ACL deficiency frequently leads to symptomatic knee instability, and is associated with both shortand long-term consequences, including meniscal and articular cartilage lesions and progressive osteoarthritic changes [4–6]. ACL rupture is generally treated either operatively or nonoperatively depending on the patient’s symptoms, age, activity level and functional demands [7–9]. Arthroscopically assisted reconstruction techniques are frequently utilized in the surgical management of ACL ruptures. Numerous techniques have been described and there is currently no consensus as to which methods yield the best functional outcome, patient satisfaction and long-term results. Currently, there is great interest in reproducing the native anatomy when reconstructing the ACL [10,11]. There is debate regarding the need for double-bundle reconstruction. Double-bundle reconstructions have been shown to improve rotational stability in vitro [12,13], but improved clinical outcomes have not been demonstrated [14,15]. With all techniques, the ultimate goal in ACL reconstructive surgery is to restore the translational and rotational kinematics of the native knee. Whether singleor double-bundle ACL reconstruction is performed, adherence to the anatomic reconstruction concept seems to be an important factor in achieving this goal [16]. Numerous factors affect outcome following ACL reconstruction, but the most common cause of revision ACL reconstruction is recurrent symptomatic instability [17]. Technical errors are the most frequent cause of recurrent instability, with tunnel malpositioning noted to be the most common error [17,18]. On the femur, tunnels are often too anterior, leading to impingement in the notch and a loss of extension. Placement of the femoral tunnel too far posterior can lead to graft laxity in flexion or excessive tension in extension. Placement of the femoral tunnel vertically in the notch may lead to decreased rotational control and a persistent pivot-shift in some cases [17]. On the tibia, the tunnel may be too far posterior, leading to a vertical graft that poorly controls anterior translation, or too far anterior, leading to impingement of the graft in the notch during extension [19]. In order to achieve a successful long-term outcome, the surgeon must consider the native ACL anatomy during ACL reconstruction. The aim of this article is to present the current knowledge of the native attachment sites of the ACL and the intra-articular landmarks for ACL reconstruction.