Fig. 1From: Influence of knee position and examiner-induced motion on the kinematics of the pivot shiftGrood/Suntay joint coordinate system, demonstrated on a bony knee model. Medial-lateral translation and flexion-extension occurs along/about the femoral fixed axis, positioned through both femoral epicondyles and consequently perpendicular to the sagittal plane. Proximal-distal translation and internal-external rotation occurs along/ about the axis, fixed to the tibial shaft. Anterior-posterior translation and valgus-varus rotation occurs along/about the floating axis, defined by the cross product of the femoral and tibial axes and therefore perpendicular to both body fixed axesBack to article page