Congenital duplication of the thumb.

Duplication or polydactyly of the thumb is among the most common congenital deformities that involve the hand. The purpose of this presentation is to review the Mayo Clinic experience with thumb duplication and to present preferred operative procedures to achieve the best clinical outcome and esthetic appearance for the hand. We propose that a combination or "best of parts", utilizing the components of both duplicates with retention of the ulnar duplicate as the base for reconstruction will provide the most functional clinical result. A clinical grading system and analysis of results from our personal experience during two different time frames provides the scientific support for our conclusions that combination procedures are preferred to simple excisions or to central joining of parts as in the Bilhaut-Cloquet procedure.