Tendon Transfers for the Hypoplastic Thumb.

Thumb hypoplasia is a component of radial longitudinal deficiency. The severity of hypoplasia can range from a slightly smaller thumb to a complete absence. Types II and IIIA hypoplastic thumbs are candidates for reconstruction to improve function, stability, and strength. There are 2 commonly used tendon transfers that can augment thumb opposition strength: the Huber abductor digiti minimi muscle transfer and the flexor digitorum superficialis opposition transfer. Both transfers use ulnar-sided structures to augment the thenar musculature. The Huber opposition transfer increases thenar bulk, but does not provide additional tissue for metacarpophalangeal stability.