Twenty-two patients (26 synostoses) surgically treated at the Istituto Ortopedico Rizzoli were evaluated. These synostoses were divided into three radiographic types: “partial” or type 1, “complete” or type 2, and “extended” or type 3. After critical analysis of the results obtained by different treatments, we conclude that operative treatment is indicated only when synostosis is so severe that effective compensation by the shoulder and the wrist joints is impossible; this occurs only in radio-graphic type 2 and 3 in which pronation is >60°. Pronation <30°, which almost always corresponds to type 1, should not be surgically corrected because such patients have little or no functional limitation of the upper extremity. In intermediate cases (30°-60°), the indication for operation should be evaluated case by case based on the following parameters: bilaterality, involvement of the dominant side, psychological and cosmetic aspects and, in particular, the efficacy of compensatory mechanisms. In patients with <70° of pronation the Sever (5) and Green and Mital (4) methods are both appropriate. For more severe cases, transverse osteotomy at the synostosis level is indicated to avoid neurovascular lesions. Double osteotomy (proximal and distal) is indicated for very severe cases in which the desired correction cannot be obtained by either of the other methods.