Abstract
PURPOSE: This study aims to identify independent risk factors for preoperative lower extremity deep venous thrombosis (DVT) in patients with non-traumatic osteonecrosis of the femoral head (NONFH), and to develop a prediction nomogram. METHODS: Retrospective analysis of prospectively collected data on patients presenting with non-traumatic osteonecrosis of the femoral head between October 2014 and April 2019 was conducted. Duplex ultrasonography (DUS) was routinely used to screen for preoperative DVT of bilateral lower extremities. Data on demographics, chronic comorbidities, preoperative characteristics, and laboratory biomarkers were collected. Univariate analyses and multivariate logistic regression analyses were used to identify the independent risk factors associated with DVT which were combined and transformed into a nomogram model. RESULT: Among 2824 eligible patients included, 35 (1.24%) had preoperative DVT, including 15 cases of proximal thrombosis, and 20 cases of distal thrombosis. Six independent risk factors were identified to be associated with DVT, including Sodium ≤ 137 mmol/L (OR = 2.116, 95% confidence interval [CI]: 1.036-4.322; P = 0.040), AGE ≥ 49 years (OR = 7.598, 95%CI: 1.763-32.735; P = 0.008), D-Dimer > 0.18 mg/L (OR = 2.351, 95%CI: 1.070-5.163; P = 0.033), AT III ≤ 91.5% (OR = 2.796, 95%CI: 1.387-5.634; P = 0.006), PLT ≥ 220.4*10⁹ /L (OR = 7.408, 95%CI: 3.434-15.981; P = 0.001) and ALB < 39 g/L (OR = 3.607, 95%CI: 1.084-12.696; P = 0.042). For the nomogram model, AUC was 0.845 (95%CI: 0.785-0.906), and C-index was 0.847 with the corrected value of 0.829 after 1000 bootstrapping validations. Moreover, the calibration curve and DCA exhibited the tool's good prediction consistency and clinical practicability. CONCLUSION: These epidemiologic data and the nomogram may be conducive to the individualized assessment, risk stratification, and development of targeted prevention programs for preoperative DVT in patients with NONFH.