Long-Term Functional and Radiological Results in Tonkin Type 3B Thumb Hypoplasia Treated With Nonvascularized Toe Phalanx Transfer as an Alternative to Pollicization.

Purpose: Parents of children with hypoplastic thumbs often reject the option of pollicization for various reasons and enquire about alternate choices. Our study aimed to assess the outcome in children who underwent nonvascularized toe phalanx transfer for Tonkin type 3B thumb hypoplasia and compare it with a similar cohort of children treated with pollicization.

Methods: At an average follow-up of 7 years for toe phalanx transfer and 6 years of pollicization, five children from each group were tested for thumb length, stability of the first carpometacarpal (CMC) joint, mobility, opposition, and donor-site morbidity. Parents were asked to report improvements in function and appearance. All cases were Tonkin type 3B thumb hypoplasia.

Results: The CMC joint was found to be stable in all children, and the Kapandji score was 6 in 3 children and 5 in 2 children with toe phalanx transfer compared to 9 in all children with pollicization. The average palmar abduction was 24°, and the average radial abduction was 36° in the toe phalanx transfer group compared to 40° and 45°, respectively, in children with pollicization. The average thumb length was 50.8% of the index finger's proximal phalanx in the toe phalanx group compared to 60 % in the pollicization group. The mean visual analog scale scores for the thumb's function and appearance were 6.8 and 6.4, respectively, compared to 9.2 and 8.8, respectively, in the pollicization group. No resorption was noted in the donor phalanx at a mean follow-up of 7 years with no donor-site morbidity other than mild shortening of the toes.

Conclusions: We noted increased palmar abduction and radial abduction in the pollicization group. No resorption was noted in the donor toe phalanx at the longest follow-up of 9 years. Toe phalanx can be considered an alternative for those children in whom a five-finger hand is a priority.

Type Of Study/level Of Evidence: Therapeutic V.