Femoral sizing jig, femur resecting system, and method

A femoral sizing jig for use in total arthroplasty of left and right knees, the jig comprising a femoral body, an external-rotation-angle arm which is movable relative to the femoral body and which sets an external angular rotation of a left or right femur, at least one of a cutting-jig guide and a cutting jig which is movable relative to the femoral body and in unison with movement of the external rotation-angle arm when setting the external angular rotation of the left or right femur, wherein the cutting-jig guide is slidable within the femoral body, the cutting-jig guide and the external-rotation-angle arm being interengaged by a pin and guide channel, the guide channel having an angled V-shaped longitudinal extent with two linear portions forming the V-shaped longitudinal extent, and a medial posterior-condylar locator which is movable in unison with movement of the external-rotation-angle arm and pivotable relative to the femoral body when setting the external angular rotation of the left or right femur, so as to maintain a fixed or substantially fixed relative distance between the medial posterior-condylar locator and a medial side of the at least one of the cutting-jig guide and the cutting jig.