# Atypical Wassel type VI thumb duplication treated with on-top plasty

## TL;DR

This paper presents a rare case of thumb duplication treated with a specific surgical technique to achieve optimal function and appearance.

## Contribution

The paper introduces the use of on-top plasty in treating Wassel type VI thumb polydactyly based on combined clinical and radiological assessments.

## Key findings

- Preoperative X-rays showed a well-formed radial thumb and an underdeveloped ulnar thumb.
- On-top plasty combined the best parts of both thumbs to achieve functional and aesthetic results.
- Clinical and radiological assessments are crucial for determining treatment strategies in thumb duplication cases.

## Abstract

Congenital thumb duplication is estimated to occur between 0.08 and 7.6 times per 1,000 live births; however its cause is still undetermined. In this report, we present a case of Wassel type VI thumb polydactyly. clinical examination revealed an optimal functional position and an aesthetically pleasing shape of the ulnar thumb as well as a superior nail and pulp. However, preoperative X-ray indicated a well formed carpometacarpal joint of the radial thumb compared to an underdeveloped CMC joint of the ulnar thumb. Through surgical procedure we combined the best parts of both thumbs with on-top plasty to achieve the most optimal outcome. In conclusion, it is important to determine an adequate treatment strategy for a patient based on both clinical and radiological assessments.