US Patent 7572258 Mitre instrument, as an example for hallux surgery

A mitre instrument for use during surgery when cutting bone in connection with shortening or extension and/or correcting of the angle of the bone. The mitre instrument includes a body (9), in which there is at least one hole for a guide pin (13) for fixation of the instrument and at least two slots or scores (3) for a cutting tool (11). The slots (3) are provided in an oblique form relative each other and in predetermined, fixed angles, which converge in a common origin of coordinates (0), at the same time as the cutting tool (11) is extendable from the lower side of the body (9) at an outlet for a guide pin (13) in origin (0) without the wedge-shaped portions (2) of the body (9) therebetween falling off.