A bone fixation device having a plastically deformable bone fixation body with at least one screw receiving aperture extending therethrough. The shape of the aperture being defined by a side wall with the side wall comprising a first threaded portion, a second smooth walled portion extending from the first threaded portion and a third smooth walled portion extending from the second smooth walled portion. The aperture having a step change in cross section between the second and third smooth walled portions defining a lip for abutment with the head of the screw.
