Perioperative inflammatory and coagulation biomarkers for predicting venous thromboembolism after lower limb fracture surgery.

backgroundVenous thromboembolism (VTE), encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE), is a preventable but serious postoperative complication in patients with lower limb fractures. Despite prophylactic measures, incidence remains high due to the interplay of trauma, immobility, and systemic inflammation. Biomarkers such as D-dimer, C-reactive protein (CRP), interleukin-6 (IL-6),and neutrophil-to-lymphocyte ratio (NLR), along with clinical recovery parameters, may improve prediction but remain under-integrated in orthopedic trauma risk models.

methodsA retrospective observational study was conducted in 106 patients undergoing surgical fixation for lower limb fractures between 2021 and 2024. All patients received risk-stratified VTE prophylaxis per Caprini score and institutional guidelines. Perioperative blood samples were collected preoperatively and on postoperative days 1, 3, and 5 to measure inflammatory, hematologic, and coagulation parameters. Clinical and surgical data, including ambulation timing and hospital stay, were recorded. VTE diagnosis was symptom-triggered and confirmed via Doppler ultrasonography or computed tomography pulmonary angiography (CTPA). Statistical analyses included logistic regression with odds ratio (OR), calibration testing, and receiver operating characteristic (ROC) analysis.

resultsTwenty-one patients (19.8%) developed VTE. Significant risk factors included advanced age, hypertension, femoral fractures, delayed ambulation, and prolonged hospitalization. Biomarkers such as CRP, IL-6, tumour necrosis factor-α (TNF-α), D-dimer, NLR, and fibrinogen were consistently higher in VTE patients, particularly on postoperative Day 3. Multivariate analysis identified age (OR 1.05, 95% CI 1.01–1.10), hypertension (OR 2.41, 95% CI 1.01–5.76), delayed ambulation (OR 3.26, 95% CI 1.22–8.70), and elevated D-dimer (OR 1.32, 95% CI 1.08–1.63) as independent predictors. ROC analysis demonstrated strongest performance for D-dimer [area under the curve (AUC) 0.78], while a combined biomarker model integrating D-dimer, CRP, IL-6, NLR, and fibrinogen improved discrimination [AUC 0.86, sensitivity 81.0%, specificity 79.5%, negative predictive value (NPV) 93.2]. Calibration plots and decision curve analysis confirmed good model performance.

conclusionThis study demonstrates that perioperative biomarkers, particularly when integrated with recovery parameters such as ambulation delay, enhance prediction of postoperative VTE in orthopedic trauma patients. While findings are exploratory due to limited events and symptom-triggered detection, the results highlight the translational potential of combined biomarker–clinical models. Development and external validation of trauma-specific nomograms are warranted to enable individualized prophylaxis and improve patient outcomes.