Abstract

Background The incidence of distal femur fractures (DFF) has shown a continuous annual increase. Preoperative deep vein thrombosis (DVT) of the lower limbs in DFF patients is associated with unfavorable clinical outcomes. Inflammation has been recognized as an essential contributor to thrombus formation, drawing increasing research attention in recent years. Objectives This study aimed to construct a predictive model utilizing inflammatory blood indicators to estimate the preoperative risk of DVT in patients with DFF. Methods A retrospective analysis was performed on 540 DFF patients admitted between January 2022 and September 2025, of whom 493 met the inclusion criteria. Clinical baseline characteristics and laboratory parameters were collected. Data normality was assessed using the Shapiro–Wilk test. For normally distributed data, intergroup differences were analyzed by one-way ANOVA, while the Kruskal–Wallis test was applied for non-normally distributed data. Independent risk factors for preoperative lower limb DVT were identified through univariate and multivariate binary logistic regression analyses. The predictive model was established using R 4.2.0, with patients randomly allocated to training and validation cohorts in a 7:3 ratio. Receiver operating characteristic (ROC) curves and corresponding areas under the curve (AUC) were computed for internal validation. Model performance was further assessed using calibration curves (CC) and decision curve analysis (DCA) in both cohorts. Results A total of 493 eligible patients were analyzed, comprising 205 cases with DVT and 288 without DVT. Comparative analysis revealed significant intergroup differences in age, NLR, LMR, white blood cell count, neutrophil count, lymphocyte count, eosinophil count, alanine aminotransferase, alkaline phosphatase, albumin, creatinine, and histories of hypertension, diabetes, and alcohol consumption (P<0.05). Univariate and multivariate binary logistic regression identified NLR (OR=0.86, 95%CI: 0.774–0.95, P=0.004), LMR (OR=1.545, 95%CI: 1.3–1.851, P=0.000), white blood cell count (OR=1.245, 95%CI: 1.152–1.353, P=0.000), neutrophil count (OR=1.563, 95%CI: 1.398–1.766, P=0.000), lymphocyte count (OR=0.151, 95%CI: 0.077–0.285, P=0.000), and eosinophil count (OR=2.343, 95%CI: 0.657–8.447, P=0.19) as independent variables associated with preoperative lower limb DVT in DFF patients. Incorporating age with these indicators, a predictive model was developed. The ROC analysis demonstrated AUC values of 0.926 and 0.939 in the training and validation cohorts, respectively. Conclusions Among the preoperative inflammatory indicators evaluated, NLR, LMR, white blood cell count, neutrophil count, lymphocyte count, and eosinophil count were identified as independent determinants of preoperative lower limb DVT in patients with DFF.