Mean contact area sensitivity reported as percent change with respect to femoral cartilage area. Full Ext = Full extension pose, Full Flex = Full flexion pose, Mid Flex = Mid-flexion pose, Mid Ext = Mid-extension pose. T1±1, T2±1, and T3±1: Perturbations in PF flexion-extension, medial-lateral tilt, and varus-valgus rotation. X±1, Y±1, and Z±1: Perturbations in PF medial-lateral, superior-inferior, and anterior-posterior displacement. The first data point in the graphical pair on the x-axis is the positive direction: flexion, medial tilt, varus rotation, and medial, superior, and anterior displacement. For example, X1±1 indicates the sensitivity of contact area to medial perturbation and then to lateral perturbation.