We report on 2 cases of traumatic pseudoaneurysm after total knee arthroplasty. In one patient, a hemarthrosis and a pulsatile antecubital mass developed 1 month after arthroplasty, prompting angiography. In the second patient, evacuation of a large hemarthrosis was performed before angiography and embolization. In both patients, the pseudoaneurysm was successfully treated without the need for surgical repair, using percutaneous thrombin injection or transcatheter embolization. No recurrence of hemarthrosis was seen in either patient at up to 24 months of follow-up evaluation. These cases show the use of angiography in reconstructed joints when acute or delayed hemarthrosis occurs, and the role of embolization techniques in this setting.