Tension-Torsion Characteristics of the Canine Anterior Cruciate Ligament—Part I: Theoretical Framework

It has been observed that the fascicles in the canine anterior cruciate ligament do not follow a straight line path between the tibial and femoral attachment sites, but rather their path is approximately helical about the ligament axis. Thus, a mathematical model for the mechanical response of a ligament was developed from the observed geometrical configuration of the fascicle. The principal result of the model indicated that a torque must always accompany the force during elongation of a ligament. The relationships between the ligament and fascicle variables are also examined in detail.