summary Polydactyly of Hand is a congenital malformation of the hand that presents with an extra digit in the hand. Diagnosis is made clinically. Treatment is usually a form of surgical reconstruction depending on the level of duplication and the specific digit involved. Etiology Forms preaxial polydactlyly thumb duplication postaxial polydactlyly small finger duplication central polydactlyly Preaxial Polydactyly (Thumb Duplication) Epidemiology incidence 1 per 1,000 to 10,000 live births Type IV most common (43%) Type II second most common (15%) demographics M>F caucasian > African Americans Genetics inheritance pattern usually unilateral and sporadic except for Type VII which is associated with several syndromes including login to view 6 more bullets Associated conditions pollex abductus abnormal connection between EPL and FPL tendons, seen in approximately 20% of hypoplastic and duplicated thumbs suggested by abduction of affected digit + absence of IP joint crease Classification Wassel Classification of Preaxial Polydactyly Type I Bifid distal phalanx Type II Duplicated distal phalanx Type III Bifid proximal phalanx Type IV Duplicated proximal phalanx (most common) Type V Bifid metacarpal Type VI Duplicated metacarpal Type VII Triphalangia Treatment operative goals of treatment login to view 4 more bullets type 1 combination procedure (Bilhaut-Cloquet) login to view 7 more bullets type 2 combination procedure login to view 5 more bullets type 3 combination procedure login to view 4 more bullets Postaxial Polydactyly (Small Finger Duplication) Epidemiology demographics 10X more common in African Americans Genetics inherited as autosomal dominant (AD) in African Americans more complex genetics in caucasians thorough genetic workup should be performed to evaluate for chondroectodermal dysplasia or Ellis-van Creveld syndrome Classification Type A - well formed digit Type B - rudimentary skin tag (vestigial digits) Treatment operative formal reconstruction with a Type 2 combination login to view 6 more bullets tie off in nursery or amputate before 1 year of age login to view 2 more bullets Central Polydactyly Epidemiology commonly associated with syndactyly extra digit may lead to angular deformity or impaired motion Treatment osteotomy and ligament reconstructions indications login to view 1 more bullet