Preoperative Deep Venous Thrombosis (DVT) after Femoral Neck Fracture in the Elderly, the Incidence, Timing, Location and Related Risk Factors

OBJECTIVE To investigate the epidemiologic characteristics of deep venous thrombosis (DVT) in elderly patients with femoral neck fracture. METHODS Retrospective analysis was performed on elderly patients with femoral neck fractures admitted to two institutions from January 2016 to October 2019. Duplex ultrasonography (DUS) was used to detect DVT. Patients' hospitalization medical records were retrieved to collect the data, which were related to demographics, comorbidities, injury and laboratory results on admission. Patients with preoperative DVT were defined as the case group and those without DVT as control group, and compared using the univariate analyses. Multivariate logistic regression analysis was used to identify the independent factors associated with DVT. RESULTS Totally, 980 patients met the predefined criteria and were included. Sixty-seven patients were diagnosed to have preoperative DVT, with incidence of 6.8% for overall, 1.7% for proximal and 5.1% for distal DVT. The mean time from injury to diagnosis of DVT was 6.0 ± 4.7 days (median, 5.0). Most (76.1%) patients with DVT had thrombi solely in the injured extremity, in contrast with 14.9% (10/67) in the uninjured and 9.0% (6/67) in both injured and uninjured extremity. Multivariate analysis showed chronic renal insufficiency (OR, 3.37; 95%CI, 1.57 to 7.28), current smoking status (OR, 2.42; 95%CI, 1.23 to 5.63), time from injury to DUS (OR, 1.26; 95%CI, 1.07 to 1.61) and PLT > 220*109/L (OR, 1.94; 95%CI, 1.31 to 3.77) were independent factors for DVT. CONCLUSION Preoperative DVT is not very prevalent following elderly femoral neck fractures, but with a certain proportion in the uninjured extremity, necessitating the more attention. These identified risk factors aid in patient counseling, individualized risk assessment and risk stratification, and should be kept in mind.