Analysis of independent risk factors for high hidden blood loss following total knee arthroplasty.

Abstract

Hidden blood loss (HBL) constitutes a substantial proportion of total perioperative blood loss after total knee arthroplasty (TKA) and may adversely affect postoperative recovery, yet factors associated with high-level HBL remain insufficiently defined. This study aimed to investigate potential risk factors and the predictive value of high HBL following TKA. A retrospective cohort study was conducted at The Affiliated Hospital of Qingdao University. We included 154 patients undergoing primary unilateral TKA for knee osteoarthritis in 2024. Participants were categorized into low HBL (<654 mL) and high HBL (≥654 mL) groups. Data were analyzed using Student's t-test, Mann-Whitney U test, and Chi-square test as appropriate. Multivariate binary logistic regression was performed to identify independent risk factors, with multicollinearity assessed via VIF. Predictive performance was evaluated using ROC curve analysis and further validated through 10-fold cross-validation in R. A two-sided P < 0.05 was considered statistically significant. Body mass index (BMI) emerged as an independent risk factor for high HBL (OR = 1.306; 95% CI, 1.147-1.487; P < 0.001). Preexisting hypertension was also associated with increased risk (OR = 2.986; 95% CI, 1.278-6.974; P = 0.011). In predictive analyses, BMI demonstrated superior discriminative ability (AUC = 0.778) compared with hypertension (AUC = 0.622), with an optimal cut-off value of 26.34 kg/m². Elevated BMI (>26.34 kg/m²) was an independent predictor of high HBL following TKA, whereas preexisting hypertension represented an associated risk factor. Routine preoperative assessment of BMI could facilitate early identification of patients at high risk, enabling individualized perioperative blood management. Integrating BMI evaluation into surgical planning allowed clinicians to offer targeted weight optimization counseling and implement tailored blood-conservation strategies, ultimately reducing HBL and enhancing postoperative recovery and patient safety.