The Second Toe-to-Hand Transfer for Full-length Thumb Reconstruction in Congenital Thumb's Grade IIIb to V Hypoplasia: MTPJ Arthrodesis Instead of Tendon Rebalansing.

Congenital thumb hypoplasia is a rare deformity of the upper extremity. The classification of thumb hypoplasia was created by Blauth in 1967 (types I to V). The base of the first metacarpal bone is absent for hypoplasia types IIIb to V, therefore, toe-to-hand transplantation is not recommended. A stable first carpometacarpal joint has been considered a mandatory factor for a successful toe-to-hand transplantation. The aim of this study is to describe a new technique for thumb reconstruction with the second toe transfer and metatarsophalangeal joint (MTPJ) arthrodesis, which can provide a five-digit hand and restore thumb functionality for thumb hypoplasia IIIb to V. We performed second toe-to-hand transplantation with MTPJ arthrodesis for 3 pediatric patients (mean age, 69 mo) with congenital thumb hypoplasia IIIb (n=2), grade V (n=1). Long-term follow-up evaluated the functions and esthetics of the hands for grade IIIb patients (n=2). We believe the second toe transfer with MTPJ arthrodesis transplantation is a promising method for reconstructing a full-length congenital or traumatic thumb absence for the pediatric population.