Ethics and (dis) advantages for the patient There are only a few publications available on implant fixation in elderly patients and currently only for fixation of the stem in patients with normal bone or osteoporotic bone. There are no RSA studies available on the Avantage® cup even though it is the standard cup in most Danish Orthopaedic Departments and one of the cups available in the Middle Region Implant Supply. The Avantage® cup is available in a similar design for cemented and cementless fixation principle. The dual-mobility concept is well proven in different implant brands over 35 years with good results on revision and dislocation (both very low) but no RSA studies on fixation are available. The current study may therefore add important and new knowledge to the literature. It is important to study both the dislocation risk as well as the mechanical stability of the bony fixation since the advantage of a low dislocation rate would be meaningless if the cups were to loosen mechanically from the surrounding bone in the mid- or longer term.