Prevalence and risk factors of preoperative deep venous thrombosis in closed patella fracture: a prospective cohort study

BACKGROUND: The preoperative prevalence of deep venous thromboembolism (DVT) of patella fracture is not well established. The study aimed to investigate the preoperative prevalence, the associated risk factors, and the locations of deep venous thrombosis (DVT) in patients with closed patella fracture. METHODS: Patients who sustained closed patella fracture between January 1, 2016, and April 1, 2019, were included. Blood analyses and ultrasonography of bilateral lower extremities were routinely performed. Data of demographics, comorbidities, mechanism of injury, fracture type, total hospital stay, time from injury to DVT, and laboratory indexes were prospectively collected and compared between groups with and with non-DVT. Multivariate logistic regression analyses were performed to determine the independent risk factors of DVT. RESULTS: Among the study cohort of 790 patients, 35 cases occurred in preoperative DVTs, indicating a prevalence of 4.4%, with 3.2% distal and 1.2% proximal DVT. Age ≥ 65 years old (OR, 3.0, 95% CI, 1.1–8.1), D-dimer > 0.5 mg/L (OR, 2.3, 95% CI, 1.1–4.8), and albumin < 35 g/L (OR, 2.5, 95% CI, 1.2–5.3) were identified to be risk factors of DVT in closed patella fracture. Among the DVTs, 30 cases (85.7%) occurred in the injured extremity, 3 cases (8.6%) in bilateral extremities, and 2 cases (5.7%) solely in the uninjured extremity. CONCLUSION: The prevalence of preoperative DVT in closed patella fracture was 4.4%, with 3.2% for distal and 1.2% for proximal DVT. We recommend individualized risk stratification and early anticoagulation for patients with risk factors (age ≥ 65 years, D-dimer > 0.5 mg/L and albumin < 35g/L).