Post-operative deep vein thrombosis in patients over sixty years of age diagnosed with closed distal femur fractures undergoing open reduction internal fixation

Background and purpose New-onset deep vein thrombosis (DVT) reportedly affects prognosis and surgical outcomes of elderly patients. However, its effect on distal femur fractures (DFFs) remains unclear. We aimed to address the epidemiological characteristics and the associated predictors for post-operative DVT in patients with closed DFFs over age 60 years old. Patients and methods We designed a prospective cohort trial at our hospital between October 2018 and June 2020 and recruited consecutive 140 patients over age 60 years diagnosed with closed DFFs. We examined location and prognosis of postoperative DVT and then conducted a three month follow-up. We used Duplex ultrasonography (DUS) to diagnose DVT in all patients and then classified the subjects into DVT and non-DVT groups. We further classified DVTs into proximal, distal, and mixed thromboses and then performed Whitney U test or t test, receiver operating characteristic (ROC) curve analysis, Chi-square test, and multiple logistic regression analysis to confirm the adjusted factors of post-operative DVT. Results We found a 35% (n = 49) overall incidence of post-operative DVTs, which occurred 5.7 days following open reduction internal fixation (ORIF). Among patients with post-operative DVTs, 53.1% (n = 26) and 10.2% (n = 5) were distal and proximal thromboses, respectively. Additionally, peroneal veins were the most common DVT sites (71.4%, n = 35). Multivariate analysis revealed that venous thrombosis at admission (odds ratio [OR], 4.619; 95% confidence interval [CI]: 2.072-10.299; P = 0.000), operation duration over 195 minutes (OR, 3.289; 95% CI, 1.155-9.370; P = 0.026), intra-operative blood loss over 325 mL (OR, 2.538; 95% CI, 1.047-6.155; P = 0.039) were the three independent risk factors of post-operative DVT. Unified antithrombotic agents after diagnosis showed that 16.3% (n = 8) of DVTs were completely recanalized, 12.6 days after first diagnosis. Conclusion Our findings indicate a strong association between venous thrombosis at admission, the longer operation duration, and considerable intra-operative blood loss with high risk of post-operative DVTs in patients over age 60 years with closed DFFs. Preventive approaches for postoperative DVTs should seek to shorten operation duration and reduce intra-operative blood loss.