A programmable screw driver and method for affixing screws into bone is disclosed. The screw driver includes a torque sensor for measuring torsional input during screw insertion, a rotational motion sensor for measuring the rotation of the screw driver, and a microprocessor. Once a surgeon rotates a screw to be affixed to the bone, the torque sensor measures the torque and sends this information to the microprocessor. Once a predetermined torque level is attained, the microprocessor begins to measure subsequent rotation of the screw driver until a predetermined rotational limit, thereby causing a signal to be sent to alert the surgeon to stop tightening.
