ORTHOPAEDIC BONE SCREW APPARATUS

摘要

A bone screw apparatus and method of implantation provides a bone screw having an elongated shaft of an oversized length with proximal and distal end portions. The distal end portion of the shaft has a cutting head. The proximal end portion of the shaft is sized and shaped to accept a driver tool, such as a drill chuck. The shaft is externally threaded along a majority of its length. A pair of opposed longitudinally extending circumferentially spaced flat surfaces are provided along the shaft. A removable head with a central opening enables the head to slide along the shaft proximally to distally. A ratcheting mechanism may prevent movement of the head along the shaft in but one direction. A central opening of the head is shaped to conform to the shaped surfaces of the shaft, so that the head and shaft can be rotated as a unit by engaging and rotating the head. The tool receptive surface portion of the head includes intersecting external surfaces of the head spaced radially away from the shaft during use.