Importance

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Abstract

A self-drilling, self-tapping screw for use in repairing broken bones. The screw is made of a high strength material selected from the group consisting of titanium alloys, chrome cobalt, and high strength resinous polymer. The screw has threw segments: a tip region, a body region and a head region. The tip and body regions have a retention thread formed over substantially their entire lengths. The tip has an included angle .alpha. in the range between 45.degree. and 50.degree.. The head region is specifically designed to maximize the torque it can withstand and minimize the amount of material removed in formation of the recess. The head has a generally frusto-conical shape with an included angle of between 90.degree. and 120.degree. to prevent pull through while minimizing the head's profile. The retention threads on the tip region and the body region have similar shapes and pitches with the pitch on the tip region being slightly smaller than the pitch on the body region. Each of the retention threads has a lead angle between 48.degree. and 52.degree., and a trailing angle between 98.degree. and 102.degree., as measured from the centerline of the screw.

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First Claim