Biomechanics of knee ligaments.

Significant advances have been made during the past 25 years in characterizing the properties of ligaments as a tissue and as an individual component in the bone-ligament-bone complex. The contribution of ligaments to joint function have also been well characterized. We have presented many studies that sought to characterize the tensile and viscoelastic properties of ligaments. As a result of these investigations, some of the most important experimental and biologic factors affecting the measurements of these properties have been identified and elucidated. The identification of the tensile properties of normal ligaments can serve as the basis for evaluating their success in healing and repair after injury. Furthermore, characterization of normal ligament function is crucial for diagnosing joint injuries as well as for evaluating reconstruction strategies and developing rehabilitation protocols. The recent introduction of robotic technology to the study of joint kinematics has resulted in significant advances in the understanding of the relative importance of ligaments to joint function. With the more accurate simulation of joint kinematics that include multiple degrees of freedom motion, data on the in situ forces in ligaments can be used to improve the treatment of ligament repair and reconstruction. More complex external loading conditions that mimic sports activities and rehabilitation protocols can also be introduced in the future. Furthermore, this technology can be extended to study other frequently injured joints, such as the shoulder.