Lamb JN, et al. - A total of 337,647 primary total hip arthroplasties (THAs) from the United Kingdom National Joint Registry were recruited by the experts in order to assess the 90-day risk of revision for periprosthetic femoral fracture correlated with design features of cementless femoral stems, and to examine the impact of a collar on this risk using a biomechanical in vitro model. The prevalence of early revision for periprosthetic fracture which happened within 90 days of surgery was 0.34% and 44.0 %. Collarless stem, non-grit-blasted finish, and triple-tapered design were the risk factors for an implant. Enhanced stability and resistance to fracture because of a medial calcar collar was observed. Hence, in order to discover the implant features that influenced the risk of early periprosthetic fracture around a cementless femoral stem, the analysis of features of stem design in registry data was a beneficial method. Further, the risk of an early periprosthetic fracture was diminished by a collar on the calcar which was validated by biomechanical testing. Therefore, in the analysis of other uncommon modes of failure post-THA, such an approach could be helpful.