The authors performed a retrospective review of their institution’s 10 year experience with polydactyly. One hundred forty-eight patients were included. Information was obtained from the medical records and telephone interviews. Patterns of polydactyly, family history, and associated conditions were noted. The findings led to the development of a classification scheme for patients with ulnar polydactyly. The authors grouped cases into five types: I- a small cutaneous nubbin, without nail or bony elements (n=1); II- an extraneous digit with a small nail and bony element, without a moveable joint or tendons and without function (pouce floutant) (n=121); III- a more formed digit with an articulation at a bifid fifth metacarpal head and hypoplasia of the proximal phalanx (n=23); IV- a fully developed sixth digit and metacarpal shaft (n=1); and V- ulnar polysyndactyly (n=2). Racial differences were noted, with African Americans presenting with 94% types I and II, versus 56% among all other racial groups. Only five of the 148 patients had ulnar syndactyly that was part of a syndrome. Treatment was ligation in 105 patients and surgery in 27. Three of the patients with ligation required subsequent surgery with a complication rate of 24% including a tender stump, an unacceptable remnant and infection. Only one patient had a complication following formal surgery.
The authors have organized the various presentations of ulnar polydactyly into a more detailed classification system based on easily identifiable variants. Their classification is compared to that of Temtamy and McKusick (Type A and B). The accepted variations in sexual (2:1 male) and handedness (L>R) are noted. Treatment for types I-IV is described as surgical ablation; this corresponds to type B polydactyly in the former system. Therefore, surgical reconstruction is only indicated in Type V (or type A) which are equivalent. The true value of this paper is to add a well-researched demographic and epidemiologic patient cohort to the literature on ulnar polydactyly.