This article discusses the anatomy and biomechanics of the posterior cruciate ligament (PCL) and PCL reconstructions and their implications for clinical management of PCL injuries. The PCL consists of two functional components, the anterolateral and posteromedial, based on their reciprocal tensioning patterns. The anterolateral has been the focus of single-bundle PCL reconstructions. Recent biomechanical studies have indicated that the posteromedial bundle also plays an important role, and double-bundle PCL reconstructions have also been proposed. The PCL works closely with the posterolateral structures in providing posterior knee stability. The effects of several surgical variables, including graft fixation, associated injuries, and tunnel placement, that can significantly affect the outcome of PCL reconstruction are discussed. With improved knowledge of the PCL, new reconstructive techniques are being developed, offering the potential of more closely replicating the anatomy and biomechanics of the normal PCL and improving clinical outcomes of PCL injuries.
Christopher D. Harner, Tracy M. Vogrin and Savio L-Y. Woo
Richard E. Debski, Shon P. Darcy and Savio L-Y. Woo
Quantitative data on the mechanics of diarthrodial joints and the function of ligaments are needed to better understand injury mechanisms, improve surgical procedures, and develop improved rehabilitation protocols. Therefore, experimental and computational approaches have been developed to determine joint kinematics and the in-situ forces in ligaments and their replacement grafts using human cadaveric knee and shoulder joints. A robotic/universal force-moment sensor testing system is used in our research center for the evaluation of a wide variety of external loading conditions to study the function of ligaments and their replacements; it has the potential to reproduce in-vivo joint motions in a cadaver knee. Two types of computational models have also been developed: a rigid body spring model and a displacement controlled spring model. These computational models are designed to complement and enhance experimental studies so that more complex loading conditions can be examined and the stresses and strains in the soft tissues can be calculated. In the future, this combined approach will improve our understanding of these joints and soft tissues during in-vivo activities and serve as a tool to aid surgical planning and development of rehabilitation protocols.