Biomechanical Variation of Double-Bundle Anterior Cruciate Ligament Reconstruction

In this chapter, the use of a robotic/universal force-moment sensor (UFS) testing system to gain quantitative data on multiple degree of freedom kinematics of the knee simultaneously with the in situ forces in normal and repaired soft tissues, is discussed. In particular, the complex interactions of the anteromedial and posterolateral bundles of the anterior cruciate ligament (ACL), as well as several key biomechanical variables in ACL reconstruction, such as femoral tunnel placement and graft fixation, were investigated. This is followed by a brief review of clinical outcome studies following ACL reconstruction along with a word of caution regarding the interpretation of these data. Finally, a novel methodology is proposed to move from in vitro to in vivo studies to gain further insight into the function of the ACL and ACL replacement grafts. All of these studies will help us to better understand the function of the ACL as well as to design scientifically based surgical procedures and postoperative rehabilitation protocols to improve patient outcome.