Experience with the GUEPAR prosthesis in 292 cases of which 103 have been followed for more than 2 years, suggests that: implanting a hinge prosthesis is major surgery on elderly patients in whom severe complications have occurred and for this reason, the operations should be reserved for extremely damaged and unstable knees; the most important local complications have been deep sepsis for which we have noted a rate of 6.6 per cent; in the treatment of sepsis, everything must be done to preserve the prosthesis because arthrodesis is difficult to obtain; pain relief has been significant as a result of the operation. The prosthetic design allows flexion of more than 90 degrees in 85 per cent of the cases and 120 degrees in 26 per cent; after two years, the results seem relatively stable. We have not observed aseptic loosening after this period but a longer observation period is necessary to be reassured on this point; patellar pain remains a major concern because this arthroplasty has not solved the problem, and other solutions will have to be found.