Pollicization of the Index Finger in Patients with Congenital Thumb Hypoplasia

Abstract

Congenital thumb hypoplasia is a radial deficiency occurring in the form of sole dysplasia or in combination with additional aberrations. Thumb hypoplasia can be categorised into 5 grades ranging from mild deformity to complete absence of the thumb. Thumb hypoplasia leads to a disturbance of grip function depending on its severity. The choice of treatment is based on the degree of thumb hypoplasia. For hypoplasia greater than grade 3B, restoration of the thumb using pollicization of the index finger is the treatment of choice. For this purpose the index finger is transformed into a thumb and is transposed to the position of the thumb with vessels and nerves being retained. The skeleton has to be shortened, rotated and abducted, followed by reconstruction of the muscles in line with the function of the new thumb. This procedure facilitates a restoration with maximal stability, sensitivity and mobility. In cases of isolated thumb hypoplasia, pollicization of the index finger yields good results persisting into adulthood. If associated aberrations are present, the outcome is less predictable because of the preexistent stiffness of the index finger. Nevertheless, associated aberrations do not represent a contraindication for index finger pollicization.