Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 10 3 2024 10 20 101 4 Mohammadreza Minator Sajjadi 1- Associate Professor, Department of Orthopedics, Taleghani Hospital Research Development Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mohammad Nazarinasab Shahid Beheshti University of Medical Sciences, Tehran, Iran. Amirali Behroozi Orthopedic Surgeon, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Amin Karimi Assistant professor of Department of Orthopedics, Taleghani Hospital Research Development committee, Medical school, Shahid Beheshti University of medical sciences, Tehran, Iran. Amir Mehrvar Assistant professor of Department of Orthopedics, Taleghani Hospital Research Development committee, Medical school, Shahid Beheshti University of medical sciences, Tehran, Iran. Seyed Amir Ahmad Safavi Naini Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2023 06 11 2024 10 20 Background: There is a paucity of evidence and controversies regarding prophylaxis strategies in low-risk patients undergoing knee arthroscopy. This study aims to evaluate the effectiveness and safety of aspirin and low-molecular-weight heparin (LMWH) in an arthroscopic anterior cruciate ligament (ACL) reconstruction for low-risk patients. Methods: We performed a preoperational evaluation a week before surgery for any sign of pulmonary embolism (PE) and deep vein thrombosis (DVT). For this purpose, we used single limited compression Doppler ultrasonography (CUS) of the lower extremities. Rehabilitation started before the time of the surgery to improve the range of motion (ROM) and quadriceps muscle function. A team of 3 orthopedists performed the procedures. The same surgical technique and graft were used with spinal anesthesia, and operation time was recorded. Results: The mean age of participants was 31.4 ± 5.6 years, with 93 individuals (67%) being men and 23% women. No cases of DVT or PE were observed. Three cases in the LMWH group and one case in the aspirin group experienced minor surgical site bleeding. One case of hemarthrosis with normal ultrasonography occurred in the LMWH group. Regarding safety and effectiveness, there was no statistically significant difference between the parallel arms. Conclusion: The use of LMWH or aspirin after simple arthroscopic ACL reconstruction in low-risk patients showed no difference in effectiveness. Hence, the routine use of thromboprophylaxis in this setting is questionable although adverse events are rare. https://jost.tums.ac.ir/index.php/jost/article/view/506 https://jost.tums.ac.ir/index.php/jost/article/download/506/386