Abstract: The present invention is comprised of a method for determining, in three dimensions, where to position fixating means (32) in a hip bone fracture structure (30) by pre-surgery analysis of at least one anteroposterior and one lateral digitized radiograph of a fracture. The method is applied to control an arrangement (40) with a tool for drilling in the correct direction in order to accomplish a best possible healing of a fractured hip bone structure (30).

Abstract: A positioning determining arrangement used for finding directions for perforations in bone structure surgery is attachable to a machine with a movable arm. The arrangement is provided with a first plate and a second plate, the first and second plates are substantially transparent to X-ray radiation in an orthogonal direction. The first and second plates are mounted in an orthogonal configuration and the first plate is provided with four round elements. The second plate can be mounted to a turnable and tiltable support for attachment t a machine. In this arrangement the X-ray magnification factor relating to two orthogonal X-ray radiographs, comprising the four round elements, taken of a bone structure is determined when two of the four round elements cover each other in both radiographs, the magnification factor being determined by a distance between two uncovered round elements of the four round elements and dependent on movement of the arm.