 Bone remodeling DXA. The expected prospective decrease in BMD of the proximal femur after insertion of an uncemented THA is most pronounced in Gruen zones 1 and 7 with decreases of respectively 13-21 and 10-31. In this study investigator intend to measure a significant difference MIREDIF in percentage changes in BMD between the two groups of 7.5. Even though several studies evaluating prospective changes in BMD around a femoral stem have been published, investigator did not find a study with precise information of the SD of the percentages in BMD. Thus, investigator estimated a SD of the changes in BMD of 8 that could be used for calculating sample size in our study. 