Tracker for a surgical instrument

An optical tracker usable with a handheld surgical instrument, the optical tracker includes a tracker frame including a mounting body, which defines an instrument engaging aperture having a longitudinal axis, and an offset body protruding proximally from the mounting body. The instrument engaging aperture is configured to receive a proximal region of the surgical instrument such that the longitudinal axis of the tracker is aligned with an axis of the surgical instrument. Three radial segments of equal proportion are defined about the longitudinal axis and collectively encircle the longitudinal axis. The tracker further includes at least six markers arranged to form at least two arrays coupled to the tracker frame and positioned such that at least one marker is positioned within each radial segment. A portion of each of arrays is coupled to the offset body and positioned proximally of the mounting body.