Early Deep Venous Thrombosis After Hip Fracture Surgery in Patients in Pharmacological Prophylaxis

Background: Venous thromboembolism frequently complicates orthopedic surgery. The aim of the study was to evaluate the overall incidence, site, and risk factors for venous thromboembolism in patients undergoing hip fracture surgery in DVT prophylaxis according to guidelines recommendations. Methods: Standard ultrasonography (CUS) was performed in the 5-6th postoperative day in all patients who underwent hip fracture surgery between 1 January and 31 December 2019. Pharmacological prophylaxis was started within 12 h from admission. In the first half of the year, dalteparin (5000 IU/day) was available while nadroparin (38 IU/kg until 3rd postoperative day and thereafter 57 IU/kg) was available in the second part of the year. Results: A total of 505 patients, 144 males and 361 females, with a mean age of 84 years, entered in the study. Post-operative DVT was found at screening ultrasonography in 121 patients (24%). Most involved distal veins (91) while proximal DVT occurred in 30. Two patients had not fatal pulmonary embolism (0.3%). Time to surgery (p = 0.0009) and ≥2 comorbidities (p = 0.0198) were independent predictive factors of DVT. Moreover, dalteparin prophylaxis was associated with a 1.7-times higher risk of developing a DVT compared to nadroparin. Conclusions: DVT occurs in 24% of patients after hip fracture surgery despite thromboprophylaxis. Time to surgery and ≥2 comorbidities were independent risk factors. The protective effects of nadroparin should be confirmed by a randomized trial. All patients with DVT were discharged with indication to anticoagulation for at least three months.