In congenital proximal radioulnar synotosis (CPRS), synostosis recurs in many cases despite release. Kanaya et al. recently reported an operative procedure including separation of the synostosis and placement of a free vascularized fascio-fat graft between the radius and ulna to prevent recurrent ankylosis. Their results show no recurrent synostosis and good range of motion in the forearm. We performed Kanaya’s procedure on two boys. Since supination was not enough, during the operation, rotation osteotomy of the ulna was performed. The first case was an 18-year-old boy. His right forearm was fixed at 20 degres pronation and his left forearm at 80 degrees pronation. We performed the modified Kanaya’s procedure including rotation osteotomy of the ulna on his left forearm. Four years after operation, he is able to rotate his left forearm to 50 degrees pronation and 53 degrees supination. The second case was a 10-year-old boy. Both forearms were more or less in the neutral position due to ankylosis. We operated on his left forearm. Three years after operation, he is able to rotate his left forearm to 0 degrees pronation and 85 degrees supination. No recurrence of synostosis in the forearm has been observed in these two cases.
