ABSTRACT
<p><b>OBJECTIVE</b>To investigate an effective therapeutic method for the secondary deformity after the correction of the Wassel type IV thumb duplication.</p><p><b>METHODS</b>9 cases of Wassel W-D Complex thumb deformities in children with postoperative secondary deformity, including 6 males and 3 female, were treated. The age ranged from 2.0 to 14 years old with an average of 5.3 years old. During the operation, the anatomical structure was dissected to observe the structure and alignment of the flexor tendon as well as anatomical structure of the joint. In the meantime, the flexor pollicis longus tendon was shifted, A2 pulley was reconstructed, joint capsule was released and contracted, the end point of thenar was shifted. Kirschner wires fixation were used for about 4-5 weeks, the brace fixation for about 3 months.</p><p><b>RESULTS</b>All the patients had radial side skin contracture of the interphalangeal joint, radial deviation of the thumb tip, radial side contracture and ulnar relaxation of the joint capsule. Flexor hallucis longus tendon was located in front of the radial side of the proximal phalanx, with no wrapped sheath or A2 pulley. Flexor hallucis longus tendon was attached to the thumb tip substrate, of which 1/3 was located in the center and 2/3 in the radial side. The thumb tip rotated about 10 degrees-15 degrees to the radial side. The patients were followed up for 6-38 months, with an average of 24 months. We adopted Tada standard to evaluate the follow-up results as excellent in 7 cases, good in 1 case, poor in 1 case.</p><p><b>CONCLUSIONS</b>Soft tissue reconstruction for the secondary deformity after the correction of the Wassel type IV-D thumb duplication is an effective method. Application of the brace after removal of Kirschner wires has an important role in preventing the secondary deformity.</p>