A bone screw (1900) for osteosynthesis is described. The screw is designed to both reduce friction and the requisite torque when tapping bone and to allow for better purchase once set in the bone, thus reducing the likelihood of loosening or back-out. The screw achieves this with grooves on the shaft (1710, 1712) or on the thread (1902, 1904) which increase the surface area.
