Background: Thumb duplication, also called radial or preaxial polydactyly, is classified
as an alteration of the radio-ulnar axis in the formation and differentiation of the hand plate, according
to the Oberg, Manske and Tonkin classification.
Objective: Radial polydactyly is a common upper limb malformation. This paper is a comprehensive
analysis of radial polydactyly, its genetic explanation, classification, surgical techniques, functional
results, as well as present and future scientific evidence on this congenital pathology.
Conclusions: Radial polydactyly occurs most frequently as an isolated defect, but it may also occur
in association with other abnormalities, or as part of a syndrome.
The Wassel classification is the universal classification for thumb duplication. One of the limitations
of it is the misclassification of the immature epiphysis.
The Wassel classification not only refers to the pathoanatomy of the polydactyly but also guides the
selection of various surgical techniques. Three well-defined surgical objectives should be ensured:
thumb alignment, stability, and an acceptable final esthetic appearance.
Tada score is a validated functional scale that takes into account the most common and limiting
complications, namely clinodactyly and instability. Based on some recent strong research evidence,
the JSSH assessment system provides the most reliable outcome of scores.
More studies are required to provide evidence-based conclusions regarding the treatment of radial