Long-term evaluation of the functional and esthetical outcomes for the new method of the toe-to-hand transfer for full-length thumb reconstruction in congenital thumb's hypoplasia in children

Congenital thumb hypoplasia is a rare deformity of the upper extremity. Incidence of thumb hypoplasia type I-V was 2-3 and type IIIb-V was 0.5-1 per 20 000 newborns per year in Latvia. The classification of thumb hypoplasia was created by Blauth in 1967 (type I to V). The base of the metacarpal bone is absent for hypoplasia type IIIb-V; therefore, toe-to hand transplantation is not recommended. A stable first carpometacarpal joint has been considered a mandatory factor for successful toe-to-hand transplantation. A technique for toe-to-hand transplantation for thumb hypoplasia type IIIb-V patients has been described in literature but overall results were not better than pollicisation. The aim of this study is to describe a new technique for thumb reconstruction with a second toe transfer with metatarsophalangeal joint arthrodesis, which can provide a 5-digit hand and restore the functionality of the thumb for thumb hypoplasia IIIb-V. Long-term follow up was done to evaluate the functions and aesthetics of the hands. A survey to evaluate aesthetical outcome for the transplantation method and pollicisation method was completed by 290 respondents. The overall population rated the aesthetic outcomes of the new transplantation method significantly higher than for pollicisation (p < 0.0001).