summary Cleft Hand is a congenital hand deformity caused by a defect in the central part of the apical ectodermal ridge during embryological development, that is characterized by the absence of 1 or more central digits of the hand or foot. Diagnosis is made clinically with the absence or shortening of the central (third) ray with the absence of radial digits and/or syndactyly of the ulnar digits. Treatment is observation versus reconstruction depending on the degree of functional limitation. Epidemiology Incidence rare (1:10,000 to 1:90,000) Demographics male:female ratio is 5:1 (more common in male) Anatomic location hands, usually bilateral login to view 3 more bullets often involves feet as well Etiology Pathogenesis theory is wedge-shaped degeneration of central part of apical ectodermal ridge (AER) because of loss of function of certain genes expressed in that part of the AER Types unilateral vs bilateral isolated vs syndromic Forms typical (central) cleft hand is characterized by login to view 1 more bullet Swanson type I failure of formation (longitudinal arrest) of central ray, leaving V-shaped cleft in the center of the hand Genetics inheritance pattern login to view 2 more bullets mutations login to view 2 more bullets affected families should undergo genetic counseling Associated conditions Ectrodactyly-ectodermal dysplasia-cleft (EEC) syndrome sensorineural hearing loss syndactyly and polydactyly Classification Manske and Halikis Classification Type Description Characteristics I Normal web Thumb space not narrowed IIA Mildly narrowed web Thumb space mildly narrowed IIB Severely narrowed web Thumb space severely narrowed III Syndactylized web Thumb and index rays syndactylized, web space obliterated IV Merged web Index ray suppressed, thumb web space merged with cleft V Absent web Thumb elements suppressed, ulnar rays remain, thumb web space no longer present Presentation History may have family history Symptoms aesthetic limitation functional limitation Physical exam absent or shortened central (third) ray may have absent radial digits may have syndactyly of ulnar digits login to view 1 more bullet Imaging Radiographs recommended views login to view 2 more bullets Treatment Nonoperative observation login to view 2 more bullets Operative thumb web space, thumb, and central cleft reconstruction login to view 2 more bullets Technique Thumb, thumb web space reconstruction web space deepening, tendon transfer, rotational osteotomy, toe-hand transfer thumb web reconstruction has greater priority over correction of central cleft thumb reconstruction should not precede cleft closure as it might compromise skin flaps Central cleft reconstruction depends on characteristic of thumb web space close the cleft proper with local tissues from the cleft and stabilize and close intermetacarpal space Prognosis Functional limitation dependent on involvement of 1st webspace Aesthetically displeasing, but not functionally limiting