A system and method for bending a bone fixation plate in the horizontal plane of the plate. The apparatus and method provide for optimization of applied bending moments by controlling the orientation of a bending tool to prevent deviation from an axis of bending. The system includes a bending bar or bars with an aperture or slot for engaging a plate or rod and a bending cage that can be in the shape of a rectangular box having a front surface separated from a rear surface by a distance. The front surface has a front elongate opening and the rear surface has a rear elongate opening. The front and rear openings are each formed by two parallel edges separated by a vertical distance and having a horizontal length. The relative dimensions of the respective bending bars and openings are such that the bending cage can be used to permit free movement of the bending bars in a direction parallel to the primary axis of the elongate openings but to prevent rotational movement of the bending bars about an axis substantial