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 substantially parallel to the length of the bending bars.