Unexpectedly High Incidence Of Venous Thromboembolism After Arthroscopic Anterior Cruciate Ligament Reconstruction: Prospective, Observational Study

Objectives The objectives of this study were to investigate the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after anterior cruciate ligament reconstruction (ACLR) using ultrasonography (US) and contrast-enhanced CT (CECT) without pharmacological prophylaxis and to identify the risk factors for DVT.Methods A prospective, observational study of 55 consecutive Japanese patients undergoing ACLR, including 10 revision surgeries, between April 2017 and September 2018 was performed. All operations were performed by the one experienced surgeon with the use of a tourniquet. Anterior cruciate ligaments were reconstructed using a single-bundle hamstring autograft. US of the leg veins was performed on the sixth or seventh postoperative day. When the patient was diagnosed with DVT, CECT was performed to detect PE. The patients were divided into two groups, those with and those without DVT. Clinical factors were compared between the two groups.Results After the ACLR, DVT was detected in nine (16.4%) patients, and CECT showed that four of them had PE (incidence, at least 7.3%). All of them were asymptomatic. The mean age was significantly higher in patients with DVT (41.915.7 years) than in patients without DVT (28.214.2 years, p=0.012). There were no significant differences in other clinical factors, including sex, body mass index, current smoker, preoperative Lysholm score, time interval from injury to ACLR, primary or revision ACLR, preoperative knee pain, operative and tourniquet times, and with or without meniscus repair between patients with DVT and those without DVT.Conclusion The incidences of DVT and PE after ACLR were 16.4% and at least 7.3%, respectively. These incidences, especially PE, were unexpectedly high and might suggest a need for thromboprophylaxis. Since advanced age was identified as the risk factor for DVT in this study, patients with this risk factor should be considered for pharmacological prophylaxis after ACLR.Level of evidence Level IV.