Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 40 2 2002 06 15 126 131 Farzan M Daneshjou Kh Mortazavi SMJ Espander R 2015 09 28 During the last 10 years, we have had 11 cases of radioulnar (RU) synostosis, a very rare congenital amomaly of the upper extremity. Only 3 of them required surgical intervention. So we evaluated these three cases of proximal radioulnar synostosis corrected by proximal derotational osteotomy. The indication for surgery was severe pronation deformity that caused functional problem. Mean age at the time of surgery was 4.5 years (3-6 years) and mean postoperative follow up was 3.5 years(1-5 years). Forearm position after surgery was 15 supination. Anesthetic and functional results in all patients were good. In only one patient it was complicated by impending compartment syndrome that was treated by conservative measures. We recommend derotational osteotomay for correcting RU synostosis in earlier age. https://acta.tums.ac.ir/index.php/acta/article/view/2595 https://acta.tums.ac.ir/index.php/acta/article/download/2595/2577