A method for determination of the inclination angle and the anteversion angle of an
acetabulum of a patient in an anatomical reference
system whose orientation is determined by the pelvic bone of the patient, taking account of any
pelvis tilt, the method comprising the following steps: a first image of the pelvic bone is provided, wherein the first image shows a frontal plane including the pelvic bone; a first inclination angle of the
acetabulum is determined using the first image; a
pelvis rotation angle is determined, which indicates the rotation angle of the pelvic bone about the normal to the frontal plane relative to an optimum
patient location position; a second image of the pelvic bone is provided, wherein the plane of the second image is rotated by an
image rotation angle relative to the frontal plane about a common section line of the two planes, preferably about the body longitudinal axis of the patient; a second inclination angle of the
acetabulum is determined using the second image; a
pelvis tilt angle is determined, which represents a rotation of the frontal plane of the first image relative to an anterior-pelvic plane in the optimum
patient location position; a linear equation
system is set up having at least two linear equations as a function of the previously determined angles; the normal vector no is expressed in polar coordinates of the anatomical reference
system; the at least two linear equations are solved for the
azimuth and polar angle of the normal vector no in order to determine the inclination and the anteversion in this way.