Transposition of Duplicated Thumb for Reconstruction of Asymmetric Radial Polydactyly

In this study, we present the long-term functional and aesthetic outcomes in patients with complicated asymmetric radial polydactyly treated with this surgical technique involving the transposition of a duplicated thumb.

We evaluated 6 thumbs in 6 patients who underwent radial polydactyly reconstruction using the transposition of duplicated thumb procedure between 2001 and 2017. The procedure was used when one of the thumbs was not obviously dominant over the other, with one having a better proximal portion and the other having a better distal portion. The average age at the time of surgery was 35 months, and at the final follow-up, average age was 86.5 months. Objective outcome values were obtained, and the Japanese Society for Surgery of the Hand evaluation form was adopted to assess functional and cosmetic outcomes.

Neither soft tissue loss nor nonunion of the osteotomy was noted. No patients reported pain or difficulties in their activities. Mean flexion-extension arc for the metacarpophalangeal joint was 72.9° (range, 8.8° extension to 64.1° flexion), and that for the interphalangeal joint was 44.0° (range, 5.7° extension to 38.3° flexion). Mean key pinch, tip pinch, and grip strength of unaffected thumb were 75.1%, 68.7%, and 81.9%, respectively. Total scores using the Japanese Society for Surgery of the Hand scoring system averaged 18.2 points, and the results were excellent in 1 case and good in 5.

Transposition of duplicated thumb can provide durable functional and cosmetic results for Rotterdam types IV and VI with asymmetric radial polydactyly in which neither thumb has adequate distal and proximal components.