Therefore, 100 patients indicated for a cementless Bihapro hip prosthesis which have signed an informed consent are included and randomised over the used centralizers using a weighted randomisation method. All patients will be treated equally. The patients are examined preoperatively, 1 day, 6 weeks, 3, 6, 12, 24 en 48 months postoperatively using an X-ray, the Harris hip score and a patient questionnaire, the Womac and SF36.