The Avantage® cup is used for all elderly patients on our department including patients with displaced medial FNF and patients with primary osteoarthritis. It may also be used for revision surgery in case of dislocation complications. Acute patients with FNF are difficult to include in studies when some pre-study investigations are necessitated and further patients with FNF are difficult to inform (pain and morphine drugged) and it is difficult to give proper time to consider study participation and perhaps call for an assessor to help make the decision. A big drop out due to difficult circumstances about project-information and consent could be a serious selection bias and could also prolong the inclusion period seriously. Mortality in FNF patients is high and poses a risk of many patients lost to follow-up during a 5-year study period and therefore demands a high estimated sample size. Therefore this study applies only to elderly elective patients with osteoarthritis scheduled for elective THA. All patients >70 years of age with osteoarthritis of the hip, who are candidates for a total hip prosthesis, will be offered participation in the study. All patients will be operated by one of two experienced hip surgeons and they will follow the usual postoperative regime at Holstebro Regional Hospital (pain treatment, physiotherapy and full weight bearing, thromboembolic and antibiotic prophylaxis). All eligible patients will be registered, those who choose not to participate, will be asked for the reason of refusal, to be able to detect possible selection bias.