Surgical classification of central deficiency according to the thumb web.

A classification for congenital central deficiency is presented. In contrast to previous classification schemes, this proposed classification is based on the characteristics of the thumb web, which are more important to the function of the hand than are the central deficiency features. Five progressive narrowings of the thumb web are identified: normal web (type I), narrowed web (type II), syndactylized web (type III), merged web (type IV), and absent web (type V). Forty-six central-deficient hands were classified and reviewed. The progressive narrowing of the thumb web correlated with progressive severity of the central defects. The proposed classification system guides and directs surgical recommendations.