ObjectiveTo investigate the effectiveness of local subcutaneous pedicled fat flap filling and separation of the synostosis area associated with radial shortening osteotomy and plate internal fixation for the treatment of congenital radioulnar synostosis.MethodsBetween February 2014 and June 2018, 36 patients (41 sides) with congenital radioulnar synostosis were analyzed retrospectively, including 21 males and 15 females, aged 2.5-4.5 years with an average of 3.1 years. The fixed pronation deformity of the forearm ranged from 30° to 90° with an average of 71.6°, and the range of motion of the elbow flexion was 120°-135° with an average of 128.2°. According to the Cleary-Omer classification, there were 8 sides of type Ⅱ, 17 sides of type Ⅲ, and 16 sides of type Ⅳ. All patients were treated by local subcutaneous pedicled fat flap filling and separation of the synostosis area associated with radial shortening osteotomy and plate internal fixation. The range of motion of the elbow, muscle strength, joint stability, and patient discomfort were evaluated by using the Broberg and Morrey elbow scoring system preoperatively and postoperatively. In addition, the ability for daily living of the affected limb was evaluated by using the Failla grading standard.ResultsRadial nerve palsy occurred in 3 cases, and nerve function recovered at 2-4 weeks after operation. All the 36 cases were followed up 6-52 months, with an average of 38 months. All osteotomy sites healed, the healing time was 5-12 weeks (mean, 6.3 weeks), and the pedicled fat flap between the radius and ulna survived when the internal fixation was taken. At last follow-up, the flexion range of motion of elbow joint was not decreased, and the pronation and supination range of motion of forearm were improved. The elbow flexion range of motion was 125°-135° with an average of 132.4°. The pronation range of motion of forearm was 15°-45° with an average of 30.1°, and the supination range of motion of forearm was 10°-40° with an average of 22.6°. At last follow-up, the Broberg and Morrey elbow scores increased from the preoperative 85.6±1.0 to 91.8±1.8, showing significant difference (t=25.593, P=0.000). Moreover, the results were good in 3 sides, fair in 9 sides, and poor in 29 sides according to the Failla grading standard before operation, with an excellent and good rate of 7.3%. At last follow-up, the results were excellent in 6 sides, good in 28 sides, and fair in 7 sides, with an excellent and good rate of 82.9%, showing significant difference when compared with preoperative value (Z=?5.781, P=0.000).ConclusionThe application of local subcutaneous pedicled fat flap filling and separation of the synostosis area associated with radial shortening osteotomy and plate internal fixation is an effective surgical method for the treatment of congenital radioulnar synostosis. It can restore the partial rotation function of the forearm and improve the quality of life of children.