Hidden blood loss and the influential factors after intramedullary nail fixation of extra-articular tibial fractures - a retrospective cohort study.

PURPOSE: There were few reports in the literature about the hidden blood loss (HBL) after intramedullary nail (IMN) fixation for extra-articular tibial fractures. Our purpose was to evaluate the amount of hidden blood loss after intramedullary nail fixation for extra-articular tibial fractures, meanwhile, identified the influential factors causing HBL. METHODS: From January 2015 to December 2017, 122 consecutive extra-articular tibial fracture patients fixed with IMN and 96 met all inclusion criteria for the chosen analysis. Preoperative hematocrit (Hct) levels on admission and postoperative Hct levels on the third day after surgery to calculate the amount of HBL. RESULTS: The mean HBL was 473.29 ± 102.75 ml after IMN fixation of extra-articular tibial fractures, the multiple regression analysis showed gender, surgical duration, and the diameter of the medullary cavity at the narrowest part of the tibia had an independent influence on HBL. CONCLUSIONS: A significant amount of postoperative HBL has occurred after IMN fixation of extra-articular tibial fractures. Surgeons should be aware that more HBL can be developed in patients who have male sex, small medullary cavity, and long-time surgical duration. HBL deserves attention to ensure patients' safety in the perioperative period of IMN fixation for extra-articular tibial fractures.