Risk Factors Analysis and the Establishment of Nomogram Prediction Model of Hidden Blood Loss After Total Hip Arthroplasty for Femoral Neck Fracture in Elderly Women

PURPOSE: To investigate the risk factors of increased hidden blood loss (HBL) after total hip arthroplasty (THA) for femoral neck fracture in elderly women and establish the nomogram prediction model for the guidance to reduce HBL in clinic. PATIENTS AND METHODS: A total of 206 elderly female patients with femoral neck fracture who underwent THA in Northern Jiangsu People’s Hospital from January 2019 to November 2021 were included. The demographic and relevant clinical information of the patients were collected. Pearson, independent sample t-test, multiple linear regression and other statistical methods were used for correlation analysis by SPSS 22.0 statistical software. Moreover, the risk factors of postoperative HBL increase in THA patients were obtained and the nomogram prediction model for the guidance to reduce HBL in clinic was established. RESULTS: HBL was 626 ± 400 mL, accounting for 72.8% ± 18.4% of the perioperative total blood loss (TBL) (799 ± 411 mL), while blood loss of HGB was 15.1±10.4 g/L. Multiple linear regression analysis showed that HBL was associated with lower age (regression coefficient = −9.271, P = 0.010), operative time (regression coefficient = 2.653, P = 0.004), preoperative blood calcium (<2.25 mmol/L) (regression coefficient = 232.492, P < 0.001), hypertension (regression coefficient = 150.352, P = 0.002) and osteoporosis (regression coefficient = 276.072, P < 0.001). R software was used to construct the nomogram prediction model and draw the ROC curve and calibration curve. The area under the curve (AUC) is 0.92 and the slope of calibration curve is close to 1. CONCLUSION: Based on the five independent risk factors including age, operative time, preoperative blood calcium, hypertension and osteoporosis, the nomogram can predict the risk of HBL after THA for femoral neck fracture in elderly women with favorable differentiation and accuracy.