The positioning of cephalon medullary nailing correlated with hidden blood loss during the perioperative period in patients with intertrochanteric fractures: A retrospective study

Hidden blood loss (HBL) during the perioperative period significantly impacts postoperative recovery and complications, yet it is frequently disregarded. This study aimed to investigate the effects of tip-apex distance (TAD) and calcar-referenced tip-apex distance (calTAD) on HBL in the treatment of intertrochanteric fractures utilizing proximal femoral nail antirotation (PFNA). The study also seeks to evaluate the possible decrease in HBL subsequent to PFNA treatment by optimizing nail positioning. A historical cohort study was conducted from January 2020 to December 2022. Patients diagnosed with unilateral acute closed femoral intertrochanteric fracture and who underwent PFNA internal fixation surgery met the inclusion criteria, and were grouped according to the value of calTAD and TAD. The participants were divided into low TAD group (TAD<20 mm) and high TAD group (TAD≥20 mm); low calTAD group (calTAD<7.625 mm) and high calTAD group (calTAD≥7.625 mm), respectively. The primary outcome measures were intraoperative blood loss (including HBL, overt blood loss, and total blood loss). Continuous data were analyzed using an independent sample t-test or Mann-Whitney U test, and categorical data were analyzed using the Pearson Chi-square test. Univariate analysis was used to evaluate the association between various indicators and perioperative HBL. A stepwise multiple linear regression analysis model was used to determine the independent factors affecting perioperative HBL. A p value less than 0.05 was considered statistically significant. A total of 131 patients were initially included, of which 80 were assigned to the calTAD group (with 61 in the high calTAD group and 19 in the low calTAD group), and 80 were assigned to the TAD group (with 34 in the high TAD group and 46 in the low TAD group). The average HBL for the low TAD group was 772.85 mL, whereas for the high TAD group it was 919.68 mL (p>0.05). The average HBL for the low calTAD group was 611.42 mL, whereas for the high calTAD group it was 904.97 mL (p<0.05). Subsequent analysis revealed that the patient's height, preoperative hemoglobin levels, changes in hemoglobin and hematocrit levels from pre- to post-surgery, and calTAD are independent risk factors influencing HBL. In summary, our investigation revealed a significant correlation between the positioning of nails in PFNA and HBL during the perioperative period. By optimizing the placement of the cephalic nail, specifically by ensuring a calTAD of less than 7.625 mm, a significant decrease in HBL can be attained. Additionally, we identified that height, preoperative hemoglobin, differences in preoperative and postoperative hemoglobin and hematocrit, and the positioning of the cephalic nail were independent risk factors for HBL.