A surgical bone fixation screw having a head, an end segment distally from the head and an intermediate shank having outwardly protruding screw threads. The improvement is a self guiding, threadless, elongated end segment having a smooth outer surface with no cutting edges, a length of at least 8 mm and preferably 15 mm and a bluntly rounded end with an outer contour that is smoothly blended to the shank. Most preferably, the bluntly rounded end is substantially a prolate hemispheroid.