Introduction:In the last years spontaneous osteonecro-sis of the knee is described to be an important, but underestimated cause of osteoarthritis of the knee. The most frequent one is located in the medial femoral condyle. Materials and methods:Between 1993 and 2000, 24 cases with osteonecrosis of the medial femoral condyle in stage II, III and IV were surgically treated. Mean age at surgery was 59 (range 33–66), 17 female, 7 male. The mean follow Ð up period was 27(range 12–44) month. The etiology was found in 27% of the cases (trauma, intraarticular steroid therapy, dislipidemy). In 73% of patients the cause was not identiþed. At 3 patients the location was bicompartimental. This surgical technique well þxed modiþes the center of the mechanical unload protecting the osteonecrosis area allowing its revascularization. Results:From 24 patients surgically treated with this technique the results were very good in 69,2%, good in 25,2%and failure in 5,6%. The very good and good results were obtained at patients with osteonecrosis of medial femoral condyle stages II and III. Conclusions:In conditions of redistribution of mechanical requirement at knee level, of good þxing HTO without bone grafting represent a technique of treatment in osteonecrosis of the medial femoral condyle allowing the revascularization of the area, improvement or even the disappearance of the symptoms well as the prevention or the delaying of osteoarthrites of the knee.