Congenital ulnar drift of the fingers. Pathogenesis, classification, and surgical management.

The classification of congenital ulnar drift is based on the tissues involved. Type I depends basically on malformation of the skin and retinaculum cutis. This is a fasciocutaneous deformity, corrected by simple release of the affected tissues followed by a free full-thickness skin graft. The deformity in Type II is more severe and the results of surgery are not as satisfactory as they are for Type I.