Prosthetic loosening and stem fractures have been the most frequently encountered complications of knee arthroplasties using the Guepar Hinged prothesis. The insufficient intramedullary fixation of the stem and the use of cement in the femur and tibia are primarily responsible for these complications. In our clinic, we have used an altered Guepar Hinged prothesis since 1975. The femoral and tibial stems are lengthened with medullary nails, resulting in stems with high bending and torsional stress capacities. The fixation strength of these special long stems in the medullary cavities is such that we no longer use cement for this prosthesis. The initial results of our cementless implantation of these special long-stem knee prostheses, and the advantages of this method are reported.