Although Total Knee Arthroplasty (TKA) surgery enjoys 90% of outcomes with good to excellent results, some patients have difficulty adjusting their gait to accommodate the new articulations inherent in contemporary implant designs. Paradoxical motions inclusive of anterior sliding and lateral pivot are examples of aberrant TKA kinematics. This handout describes the utilization of a computational kinematic simulator to compare the motion of six contemporary TKA designs with recent in-vivo kinematic data of the healthy unoperated knee through deep flexion.