Instantaneous center of rotation shifts in symptomatic anterior cruciate ligament deficient knee joints

摘要

The purpose of this investigation was to document the influence of the anterior cruciate ligament (ACL) in controlling the dynamic interaction between the femur and tibia. Twenty subjects were initially selected to participate based on the results of arthroscopic and proprioceptive tests which established the presence of a uni-lateral, third degree rupture of the ACL. A spline function established the best fitting curve of the instant center (IC) coordinates obtained throughout the ROM. Displacement variables were extrapolated from joint rotation profiles generated from these coordinates. Abnormal displacement migrations of the IC parameter were demonstrated to occur in extension. Migration displacements evaluated between 30$ sp circ$ and 0$ sp circ$ shifted anteriorly 5.07 $ pm$ 1.86 mm for intact knees and 6.97 $ pm$ 2.06 mm for involved knees. This was determined to be significant at the 0.05 level of confidence and correlated well with clinical findings. Mean migration displacements evaluated in flexion (between 100$ sp circ$ and 70$ sp circ)$ were not found to differ significantly between knee conditions.