Background Venous thromboembolism (VTE) is an important complication after major orthopedic surgery.Pharmaceutical methods represent the main strategy of VTE prevention.The use of aspirin in VTE prevention is still controversial worldwide,especially in China.The purpose of this study was to evaluate the role of aspirin combined with mechanical measures in the prevention of VTE after total knee arthroplasty (TKA).Methods Between January 2012 and May 2013 and in accordance with the inclusion criteria,120 patients undergoing TKA were randomly allocated to two groups.To prevent VTE,patients in group A received aspirin combined with mechanical measures postoperatively,while patients in group B received low-molecular-weight heparin (LMWH) sodium and rivaroxaban sequentially in combination with mechanical measures postoperatively.All surgeries were performed by one surgeon using a posterior-stabilized cemented prosthesis.The two groups were followed up and compared for the incidence of deep vein thrombosis (DVT) by duplex ultrasound scan and clinical VTE events.The adverse events,the blood loss index,and the cost of VTE prevention were also compared.Results DVT was detected in 10 of 60 patients in group A (16.7％,95％ CI:7.3％-26.1％) compared with 11 of 60 in group B (18.3％,95％ CI:8.5％-27.8％) (P=0.500).There is no statistical evidence supporting the inferior effect of aspirin in preventing DVT as compared with the other medications.There were no cases of symptomatic VTE or death during the follow-up period.Area of ecchymosis was lower in group A than in group B,and the differences were statistically significant.Patients in group A had the lower blood loss index as compared with patients in group B.No transfusion cases were found in both groups.The differences were statistically significant.The cost of VTE prevention analysis indicated a cost reduction using aspirin in group A compared with using LMWH and rivaroxaban in group B.Conclusion Aspirin combined with mechanical measures had a good effect on prevention of VTE after TKA and resulted in lower cost,less blood loss,and less subcutaneous ecchymosis.