A combined guiding and fitting element for an acetabular cup implant which comprises i) a guiding instrument for an acetabular cup implant which comprises: - a hollow support structure having an inner surface that is designed to fit with the outer surface of a fixation element of an impactor, and - one or more contact elements which fit onto areas of the bone surrounding an acetabular cup implant zone in at least three contact points, wherein the one or more contact elements are designed such that the angle between the plane through the central axis of the implant and one contact point of the at least three contact points and the plane through the central axis and the adjacent contact point of the at least three contact points is never greater than 180°; and said one or more contact elements and specific areas of the bone surrounding the acetabulum engage by means of a unique and tight fit; ensured by a complementarity between at least one of said one or more contact elements and the patient-specific morphology of the bone surrounding the acetabulum, and ii) an impactor for press-fitting an acetabular cup implant comprising: - a stem comprising a drive member, a hinge element and an impact element; and - a fixation element, wherein said hinge element of the stem forms a ball joint with said fixation element allowing movement of the orientation of said stem relative to said fixation element; wherein said combined guiding and fitting element comprises one or more locking features,, for interlocking of said guiding instrument and said impactor; characterized in that said hollow support structure of said guiding instrument has an outer surface which fits securely onto an acetabular cup implant. i) a guiding instrument for an acetabular cup implant which comprises: - a hollow support structure having an inner surface that is designed to fit with the outer surface of a fixation element of an impactor, and - one or more contact elements which fit onto areas of the bone surrounding an acetabular cup implant zone in at least three contact points, wherein the one or more contact elements are designed such that the angle between the plane through the central axis of the implant and one contact point of the at least three contact points and the plane through the central axis and the adjacent contact point of the at least three contact points is never greater than 180°; and said one or more contact elements and specific areas of the bone surrounding the acetabulum engage by means of a unique and tight fit; ensured by a complementarity between at least one of said one or more contact elements and the patient-specific morphology of the bone surrounding the acetabulum, and - a hollow support structure having an inner surface that is designed to fit with the outer surface of a fixation element of an impactor, and - one or more contact elements which fit onto areas of the bone surrounding an acetabular cup implant zone in at least three contact points, wherein ii) an impactor for press-fitting an acetabular cup implant comprising: - a stem comprising a drive member, a hinge element and an impact element; and - a fixation element, wherein said hinge element of the stem forms a ball joint with said fixation element allowing movement of the orientation of said stem relative to said fixation element; wherein said combined guiding and fitting element comprises one or more locking features,, for interlocking of said guiding instrument and said impactor; characterized in that said hollow support structure of said guiding instrument has an outer surface which fits securely onto an acetabular cup implant. - a stem comprising a drive member, a hinge element and an impact element; and - a fixation element, wherein said hinge element of the stem forms a ball joint with said fixation element allowing movement of the orientation of said stem relative to said fixation element;