Abstract In the field of orthopedics, acute pulmonary embolism (APE) associated with deep venous thrombosis (DVT) is a serious complication following surgery and leads to death if undetected. Although an examination for the presence of APE after surgery has been well established in other countries, there are few reports on APE after orthopedic surgery in Japan. Here, we describe a case of asymptomatic APE associated with DVT after total knee arthroplasty (TKA) in a patient with rheumatoid arthritis (RA). Because it is difficult to determine the clinical features of APE prior to the initiation of angiography, we used a perfusion lung scan, which is a useful tool for detecting asymptomatic APE. We successfully identified APE in the TKA patient with RA, and continuous intravascular infusion of a thrombolytic agent and an anticoagulant was an effective treatment in this case. Our report clearly shows that a well-established procedure for diagnosis, as well as therapeutic guidelines, are essential for detecting systemic thromboembolism in patients after orthopedic surgery.