The application relates to a method of orienting a bone-milling cutter and an impact instrument for a hip-prosthesis cup in an acetabulum. The method includes initially positioning a manipulation cup by a manipulation joint head and representing this position by at least one guide rod or fixation rod that is fixed in a bone. The method also includes removing the manipulation cup and adjusting a position of both the bone-milling cutter and the impact instrument with respect to either the guide rod itself or a guide rod that is attached to a holding device disposed on at least one fixation rod.
