Aims: We studied the outcome of a progressive correction of the rotation malalignment syndrome with combined supracondylar and proximal tibial osteotomy. We evaluated the associated anterior knee pain in most patients due to patellar maltracking. Methods: Between 1991 and 2002, 56 combined femoral and tibial osteotomies were performed in 37 patients (mean age 18 years). Ilizarov method was used for correction of the idiopathic anteversion with combined tibial external rotation. The þxator was kept in place for an average of 4.4 months and mean follow up was 3 years. Results: In more than 90% of the patients with preoperative anterior knee pain, the symptoms diminished or disappeared. All alignments were corrected adequately. A temporary neuropraxia of the peroneal nerve was seen with acute derotation of the tibia. This technique was abandoned. Four patients were not satisþed for cosmetic reasons, due to the multiple scars from the pins especially on the upper thigh. Postoperative problems were uncommon. There was one undisplaced femoral fracture after removal of the frame and one overcorrection was seen, that could be treated with a new osteotomy with progressive external derotation. Conclusions: The progressive derotation technique using the Ilizarov method allows a reliable correction of a rotational malalignment syndrome with a concomitant improvement of anterior knee pain