An Unusual Case of Polydactyly

Abstract

Polydactyly is defined as a congenital anomaly of the hand or foot with the presence of supernumerary digits. The frequency of polydactyly varies widely among populations. It can occur as an isolated condition or as a feature of a congenital condition. In the literature, the condition is commonly described in combination with an apparent congenital deformity. We describe a case of polydactyly with no other obvious, macroscopically visible anomaly. A 21-year-old man presented with a sprained left ankle. On examination, a slightly irregularly shaped fifth digit of the left foot that appeared like a tailor's bunion was observed. The patient reported slight weight-bearing pain and tenderness over the navicular bone. No fractures were seen on radiographs, but they revealed an os tibiale externum, an extra metatarsal bone conjoined distally with the fifth metatarsal, and an extra hypoplastic proximal phalanx. No obvious signs of deformity were present. A bunionette, which was an extra hypoplastic proximal phalanx, was observed at the base of the fifth toe. Few published reports have described isolated polymetatarsia, and none of those describe supernumeral digits. A comprehensive search of the literature found no cases identical to ours.