Tapered bone screw with continuously varying pitch

摘要

A bone screw having a continuously varying pitch includes a tapered root portion having a relatively small diameter on a leading end of the screw and a larger trailing diameter. The pitch of the screw decreases between the leading and trailing ends thus causing the bone fragments in a fracture to be drawn together when the screw is installed across the fragments. The radially outer diameter of the threads increases between the leading and trailing ends thus causing each successive thread portion to cut into bone radially outwardly from the preceding thread portion thereby providing uncut bone in which the succeeding threads can gain purchase.