In recent years, there has been an apparent increase in the incidence of pulmonary embolus after joint arthroplasty at our institution. We hypothesized the use of sophisticated imaging modalities such as the multidetector computed tomography scan, with better sensitivity, resulted in an apparent increase in the incidence of pulmonary embolus. We studied all patients with pulmonary embolus after joint arthroplasty between 2000 and 2005. The incidence of pulmonary embolus increased from 0.21% (six of 2859) when VQ scan was the modality of choice to 0.98% (50 of 5095) during the time spiral computed tomography was used to 1.72% (89 of 5179) in recent years when multidetector computed tomography was used. Despite the apparent increase in pulmonary embolus, we observed no change in mortality during the study period. Surgeons should be aware of the challenges sophisticated imaging modalities in general and modern imaging introduce for pulmonary embolus in particular. Extremely sensitive imaging tests with unknown specificity have resulted in an increase in diagnosed pulmonary embolus. However, diagnosing pulmonary embolus generates implications for further treatment such as prolonged anticoagulation and/or inferior vena cava filter insertion with potential for catastrophic complications. The challenge is to distinguish which require treatment and which do not.