Background Worldwide use of cementless fixation for total hip arthroplasty (THA) is on the rise despite some evidence from the world's registries suggesting inferior survivorship compared with cemented techniques. The patterns of bone loss associated with failed cementless and cemented THAs may prejudice the results of future revision procedures; however, this has not been documented. Questions/purposes The purpose of this study was to compare (1) the risk for rerevision of first revision THA; (2) the patterns of femoral bone loss at the time of first revision of primary THA; (3) the reasons for first revision of primary THA; and (4) the time to first revision of primary THA between primary cementless and cemented femoral components. Methods Primary THAs with cemented (n = 1791) and uncemented (n = 805) femoral components that subsequently sustained first revision of the femoral component were identified from the Danish Hip Arthroplasty Registry (DHR). As of 2012, 120,988 primary THAs and 19,282 revisions were registered in the DHR with completeness of 97% and 90% for primary and revision THA, respectively. Median followup for revisions of primary THA with cemented and cementless femoral component was 4 years (range, 0-17 years) and 2 years (range, 0-16 years), respectively. Survival of first revision THA, with second revision of the femur as outcome, was evaluated using hazard ratios (HRs) with 95% confidence interval (CI) adjusting for potential confounding. All patient-and surgery-related data are collected from Danish medical databases. Recording of bone defects in the DHR is based on surgeons' intraoperative findings. Results With the numbers studied, we found no differences in the risk of second revision between the overall cohort between cementless and cemented techniques (HR, 1.32; 95% CI, 0.97-1.80; p = 0.076); however, a second revision for Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. Conclusions We found no differences in the risk of second revision in the overall cohort between cementless and cemented techniques; however, we observed an increased risk for rerevision THA performed on patients \ 70 years whose index THAs were performed using cementless components when looking at all causes for revision, even after adjusting for the most likely confounding factors. Our data suggest that increased use of cemen...