An osteocartilaginous exostosis developed in a 4-year-old boy in whom a distally-based lateral supramalleolar adipofascial flap had been used to cover a defect in the dorsum of the foot. The bony exostosis was first noticed four months after the operation. It was excised with no complications and there has been no recurrence after two years follow-up. The exostosis was thought to result from stripping the perichondrium over the epiphyseal plate while the flap was being raised. This unique complication has not to our knowledge been reported after harvest of a flap before. © 2012 Informa Healthcare.