Xu X, Zhu Q, Yang Y, et al. - This study was sought to evaluate the blood loss associated with femoral shaft fractures (FSFs) treated with the intramedullary nail or locking compression plate fixation, as well as to identify the relative affecting factors for perioperative hidden blood loss (HBL). Between January 2009 and January 2020, researchers enrolled a total of 131 consecutive patients with FSFs, including 90 cases for intramedullary nail (Nail group) and 41 cases for locking compression plate fixation (Plate group). They obtained and examined demographics and perioperative data. They computed total blood loss (TBL), visible blood loss (VBL), HBL, and percentage of HBL (PHBL) based on hematocrit (Hct) change. The results of this study exhibited that individuals of FSFs had significant TBL and HBL, the amount of which was much larger than that observed intra-operatively. It was shown that two readily available preoperative factors for nail fixation and Type-C were correlated with a higher likelihood of more HBL. Thus, the study further illustrated that regular perioperative monitoring and timely blood transfusion were crucially important for patients to avoid possible risks of anemia and facilitate recovery.