True Polydactyly

Two patients who presented for evaluation of unrelated maladies were noted to have true polydactyly. Both patients—a 32-year-old white man (A) and a 35-year-old African American woman (B)— had a duplicate left thumb. There were no other associated congenital abnormalities. Dr Sunita Puri comments that polydactyly can occur on the foot as well as the hand. The anomalous growth may range from a small, hypoplastic soft tissue deformity to a fully developed digit with phalanges and metacarpals. True polydactyly can be distinguished from a supernumerary digit, which is characterized by the presence of a thin pedicle that attaches the abnormal growth to the primary digit. Duplicates of the thumb and the fifth finger occur most often. Fifth finger polydactyly is more common in black persons than in whites.¹ Frequently, the patient has a family history of the condition. Radial or ulnar side location of the extra digit of the hand is significant in identifying certain syndromes in children, such as trisomy 13 syndrome and chondroectodermal dysplasia (Ellis-van Creveld syndrome). Small extra digits without skeletal involvement can be tied off or easily excised; more fully developed duplicates require more complex surgical removal. These patients claimed to be comfortable with the anomaly and refused surgery for cosmesis.