Screw thread with flattened peaks

An implant system for use in orthopedic surgery for fixation of bone, comprising:

• a bone plate having an upper surface and a lower surface;
• at least one hole extending through the bone plate upper surface and lower surface, the at least one hole having a threaded portion;
• at least one bone fastener comprising a shaft having a first core diameter and a first thread projecting outwardly from the first core diameter, the shaft configured to engage bone and a head formed on the shaft, the head being tapered at an angle towards the shaft, the taper of the head forming a plurality of second core diameters each larger than the first core diameter of the shaft, the head having a second thread projecting outwardly from at least a portion of the plurality of second core diameters, the second thread being formed to engage the threaded portion of the at least one hole of the bone plate,
• wherein the bone fastener includes a central longitudinal axis through the shaft and the head, and
• wherein the second thread has a profile in cross section including a plurality of peaks, the plurality of peaks having a flat portion intermediate two curved portions.