[Sliding axis endoprosthesis in severe unstable gonarthrosis and as revision prosthesis]

42 patients with 45 implanted total knee endoprostheses (sliding axis endoprosthesis Lübeck, Rp. SG implant) were investigated clinically according to the score of the Knee Joint Society in mean 27.9 months postoperatively. Mean total knee score increased from 34.9 +/- 14.7 to 72.5 +/- 3.1 and mean total functional score could be ameliorated from 40.2 +/- 25.7 to 55.7 +/- 4.5 (maximum points: 100). Evaluation of X-rays (anterior-posterior and lateral views) exhibited a satisfactory position of the prosthesis. Comparison between cemented and cementless implants as well as between primary implants and revision did not reveal any statistically significant differences. Patients with a longer follow-up period (59.8 months) showed results comparable to the mean of the total group. Frequently observed malposition of the axis of more than 3 degrees requires modifications of the orientation instruments. For revision surgeries a modular system for elongation of the stem would be desirable.