OBJECTIVETo investigate the optimal surgical timing and treatment of congenital duplication of the thumb in children.

METHODSA clinical study was performed on 154 fingers of the 132 patients (including 85 males, 47 females;mean age (1.53 +/- 2.47) years; ranged from 2 months to 13 years). Duplicated thumbs were surgically treated from December 2007 to February 2012. All patients underwent detailed physical examination and radiological assessment. Surgical methods should be selected according to the age, Wassel classification and deformity. The operation steps included resection of the most hypoplastic thumb, followed by skin flap plasty, tendon shift (transplantation) , reconstruction of collateral ligament and articular capsule. 11 cases over the age of 6 underwent osteotomy discretion as appropriate.

RESULTSA total of 117 fingers of the 104 patients were followed up for an average 36. 7 months (range,6-55 months). We adopted upgrade Tada standard to evaluate the follow-up results as excellent in 77 thumbs, good in 21 thumbs, fair in 15 thumbs and poor in 4 thumbs. Three thumbs appeared secondary angular deformity 2 years after operation and one thumb appeared residual osteoepiphysis in the radial side of metacarpophalangeal joint 3 years after operation. The appearance and the function were almost normal after second operation.

CONCLUSIONSThe optimal surgical timing of congenital duplication of thumb should be based on the appearance of thumb ossification center. The surgical timing of Wassel type- I and II should be chosen at 1. 5 years old when the ossification center of distal phalanx appears, Wassel type-III and IV should be chosen at 1 year old when the ossification center of proximal phalanx appears, Wassel type-V and VI should be chosen at 2. 5 years old when the ossification center of metacarpal appears, and Wassel type-VII should be chosen at 2. 5 years old. The surgical method should be selected on individualized principle. The key points are reconstruction of collateral ligament, tendon and articular capsule and correction of ulnar deviation (or radial deviation).