title: Type A ulnar polydactyly of the hand: a classification system and clinical series.
abstract: OBJECTIVE
  To propose a classification system for type A ulnar polydactyly based on radiographic findings and characterize the demographic features of patients with these deformities.
  
  
  METHODS
  We identified 49 patients with type A ulnar polydactyly of the hand who were seen in our institution over 20 years. Patients' medical records and radiographs were retrospectively reviewed and used to distinguish morphological subtypes.
  
  
  RESULTS
  Ninety-six percent of the deformities (64/67) were allocated to 1 of the 5 subgroups of our suggested classification, and the type that originated from the metacarpophalangeal joint was the most common. Sixty-nine percent of patients in our series (34/49) had either bilateral type A or a contralateral type B ulnar polydactyly, and 63% (31/49) had ulnar polydactyly of one or both feet. Twenty-four percent of patients (12/49) had associated syndromes or congenital anomalies involving areas other than the hand or foot. The most common syndrome associated with type A ulnar polydactyly was chondroectodermal dysplasia (n = 3). Sixty-five percent of the patients (32/49) were Caucasian, 20% were Hispanic (10/49), 12% were African American (6/49), and one was Asian. The percentage of African Americans in our series was similar to that in the general patient population seen in our institution.
  
  
  CONCLUSIONS
  The majority of type A ulnar polydactyly can be classified into 1 of 5 morphological subtypes that have potential clinical relevance regarding surgical treatment. In patients with type A ulnar polydactyly, contralateral hand and foot polydactyly is frequent. Associated congenital anomalies and syndromes can also be present.
authors: Texas Scottish Rite Hospital for Children, Dallas, TX 75219, USA.
authors: Tamir
authors: T
authors: Pritsch
authors: Marybeth
authors: M
authors: Ezaki
authors: Janith
authors: J
authors: Mills
authors: Scott N
authors: SN
authors: Oishi
mesh_terms: D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005385:Fingers / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D017689:Polydactyly / Q000145:classification* / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D014457:Ulna / Q000002:abnormalities / Q000000981:diagnostic imaging