Anatomy and Biomechanics of the Posterior Cruciate Ligament

Abstract

This paper describes the anatomy and biomechanics of the posterior cruciate ligament (PCL). The PCL fibers were divided into anterolateral (aPC) and posteromedial (pPC) bundles, attaching to the roof and to the medial wall, respectively, of the femoral intercondylar notch. One or both menisco-femoral ligaments were present in 97% of knees. The aPC was slack in knee extension and tight in mid flexion; the pPC had the opposite behavior and also tightened in deep knee flexion. Tensile tests found 86% of PCL strength in the aPC (aPC, 1.62 kN; pPC, 0.26 kN), and the aPC withstood significantly greater stress. Posterior drawer tests found that structures other than the PCL were the primary restraint near knee extension; the aPC was dominant in mid-knee flexion and the pPC in deep flexion. The PCL had little effect on tibial rotation. These findings led to guidelines for PCL and posterolateral corner reconstruction.