Wassel VI Duplications: A Report of 2 Cases, Soft-tissue Anatomy, and Reconstructive Approach.

Preaxial polydactyly represents an embryologic failure of formation and differentiation that is most commonly classified according to the level of bony duplication. The soft-tissue anatomy and approach to reconstruction of a Wassel VI thumb, an uncommon variant in which complete duplication begins at the metacarpals has not been extensively discussed in the literature. Here, we present 2 patients with a Wassel VI duplication and a shared soft-tissue variant of anomalous insertion of the opponens pollicis muscle onto the radial hypoplastic digit. A critical component of thenar reconstruction involves preservation and reinsertion of the opponens muscle into the dominant and preserved metacarpal.