[Morphologic changes in artificial prostheses following para-articular knee bypass operations].

A report is presented on two helically reinforced polytetrafluoroethylene vascular prostheses in the femoro-popliteal (below-knee) position which thrombosed in the early postoperative period. Lateral angiography in the 45, 90 and 120 degree position of the knee joint showed short (2 mm) mild stenosis like kinking in case 1. At reoperation in case 2 the prosthesis was kinked in the longitudinal axis. Femoro-popliteal allografts across the knee joint should accomplish the following demands: 1. no kinking on postoperative lateral angiography with the knee joint bent and 2. intact prosthesis at reoperation.