Abductor digit minimi opponensplasty: technique, modifications, and measurement of opposition.

The abductor digiti minimi is one of several muscles described as transfers for restoration of thumb opposition, a critically important function. This operation, also known as the Huber opponensplasty, is most commonly used for reconstruction of opposition in children with type 2 or 3a thumb deficiency, when it is often combined with Z-plasty of the thumb-index web space and metacarpophalangeal ulnar collateral ligament reconstruction. In our experience this operation reliably improves thumb opposition for children with this thumb deficiency.