The duration of the ischemic time in total knee arthroplasty is currently considered to be an important predictor for the development of arterial thrombosis. In the following, we describe two patients with thrombotic occlusions of the popliteal artery. After the first one had been operated on under ischemic conditions, the ischemic time was limited to the cementing phase in the second case on the basis of this experience, but an arterial occlusion occurred in this case as well. In neither case did immediate vascular surgery lead to clinical restrictions. Our observation demonstrates that arterial thromboses can occur regardless of the duration of ischemia and that surgery should therefore be performed without ischemia if risk factors are present.