Background: Congenital thumb deformities account for one-third or more of all cases of congenital hand deformity.However, the current classification schemes of congenital thumb hypoplasia are no longer adequate due to their lack of adaptability to increasing knowledge in the field. Hence, a modified system with the potential to adapt to ongoing advances in knowledge and understanding is desperately needed.Methods: Based on the photographs collected from thousands of cases of congenital deformities of the hand and upper limb over multiple decades in our department, we subdivided thumb hypoplasia according to the variables of morphological characteristics, anatomical structures, functional status, the relationship between thumb deformity and hand deformity, the relationship between congenital hand deformity syndrome and thumb hypoplasia, and the selection of treatment methods.Results: A total of 10 types were presented, which were elucidated with nomenclatures as well as pathological feature and symptoms.Conclusion: This modified system may shed additional light on the classification of congenital thumb anomalies,which will assist in a more effective selection of treatment modalities and offers significant benefits to both patients and practice.
