Introduction to congenital differences and genetics

The history of classification systems for upper extremity congenital differences will be discussed, including a review of the historical American and European classification literature and terminology. The origin of the Swanson International Federation of Societies for Surgery of the Hand classification system is reviewed, as well as its limitations in practical application. Based upon recent information in developmental biology and genetics, the more contemporary classification systems are presented that attempt to organize associated congenital upper extremity diagnoses within common etiologic groupings. The proposed Oberg, Manske, and Tonkin classification system takes this new scientific data into consideration and is presented as a potential replacement for the current IFSSH classification system.