Radial Polydactyly.

» Radial polydactyly is one of the most common congenital anomalies of the hand, with an incidence of 0.08 to 1.40 per 1,000 live births; it requires surgical treatment early in life.» Polydactyly occurs during weeks 5, 6, 7, and 8 of embryogenesis, principally due to misregulation of the sonic hedgehog protein within the developing limb bud.» The Flatt classification system of preaxial polydactyly (types I to VII), as published by Wassel, categorizes preaxial polydactyly based on osseous abnormalities, but it has substantial limitations.» For improved function and appearance, preaxial polydactyly ideally requires surgical intervention at an early age (between 1 and 2 years of age) before the development of fine motor skills.