The Incidence of Venous Thromboembolism (VTE) After Hip Arthroscopy (SS-43)

Abstract

The true incidence of VTE following hip arthroscopy is not known. Salvo et. al. have recently reported a symptomatic DVT rate of 3.7% following these procedures. This number was based on a retrospective study in which only symptomatic patients were tested. However, the clinical signs and symptoms of VTE in post operative patients lack sensitivity and specificity. Thus, it is important to screen all patients to obtain a more accurate incidence of VTE. Understanding the true rate of VTE will allow us to better determine what type of VTE prophylaxis, if any, is needed for these patients. We postulate that prolonged traction on the limb as well as proximity to pelvic vasculature may place patients undergoing hip arthroscopy at increased risk of developing VTE. The purpose of this study is to determine our institution's incidence of venous thromboembolism after hip arthroscopy. This is an IRB approved retrospective study. Over the course of one year (August 2010-August 2011), four surgeons that routinely perform hip arthroscopy began a protocol to screen all patients post-operatively for deep venous thrombosis (DVT) using bilateral venous duplex ultrasound at or about the two-week post-operative time point. Patients did not receive mechanical prophylaxis intra-operatively, and were excluded if they received pharmacologic prophylaxis post-operatively. Patient risk factors for VTE were assessed and recorded. Peri-operative factors, such as weight bearing status after surgery, traction time, and anesthesia type were recorded. We identified 144 patients over the course of this time period that underwent hip arthroscopy. 61% of were women and 39% were male. Five patients were excluded for receiving pharmacologic prophylaxis after the procedure. The average age was 37.7 (SD=12.0). The average BMI was 25.9. The average traction time was 58.9 minutes. Ninety six percent of patients received general anesthesia. Most patients (71%) were partial weight bearing after the procedure. Overall, our incidence of VTE was 1.4 percent (2/139). There were two symptomatic venous thromboembolic events noted; one DVT and one pulmonary embolus. One patient had no risk factors; the other was overweight and routinely took oral contraceptives. Of the entire patient pool, 81 obtained a follow-up ultrasound. There were no cases of asymptomatic VTE. To our knowledge, this is the first study using routine ultrasound to screen patients for post-operative VTE after hip arthroscopy. In patients undergoing hip arthroscopy, the rate of post-operative VTE is low, despite the use of prolonged axial traction and surgical proximity to the pelvic veins. We believe that routine use of pharmacologic prophylaxis is not indicated unless the patient has other risk factors that would place them at a high risk for developing VTE after a routine outpatient surgical procedure.