The OMT Classification of Congenital Anomalies of the Hand and Upper Limb.

The Oberg, Manske and Tonkin (OMT) Classification of congenital anomalies of the hand and upper limb uses dysmorphological terminology, placing conditions in one of three groups: Malformations, Deformations and Dysplasias. The main group, Malformations, is further subdivided according to whether the whole of the limb is affected or the hand plate alone, and whether the primary insult involves one of the three axes of limb development and patterning or is non-axial. The common surgical diagnoses, such as thumb duplication and thumb hypoplasia, are then placed within this framework. Recently the International Federation of Societies for Surgery of the Hand Scientific Committee for Congenital Conditions approved the OMT Classification as a timely and appropriate replacement of the previously accepted Swanson Classification. This review charts the development of and modifications to the OMT Classification and its current status.