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American Association for Hand Surgery
Meeting Home Accreditation Final Program
Theme: Inclusion and Collaboration Theme: Inclusion and Collaboration

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Institutional Review of Radial Polydactyly
Mollie M Walton, BS; Timothy Schaub, MD; Joseph Kelling, MD; Alex Pham, MD; Lukas Foster, BS; Creighton University School of Medicine, Phoenix, AZ


The Wassel classification system for radial polydactyly, introduced in 1969, is most familiar among trained hand surgeons, and is the most widely used system described in literature. Congenital radial polydactyly has not been well-analyzed in the Hispanic population. We believe that a we have a significant sample of cases of Hispanic patients with radial polydactyly that can be compared to existing literature using the Wassel classification.


Hand radiographs from our institution, St. Joseph's Hospital and Medical Center, in Phoenix, Arizona collected during the ten-year period of January 1, 2016 to January 16, 2016 were used for this investigation. All patients over the age of 18 were excluded from the study. Of 856 total patients, 60 had radial polydactyly as determined independently by both a fellowship-trained hand surgeon and a pediatric radiologist. The images from these 60 patients were reviewed and classified according to the Wassel system. Upon chart review of these 60 patients, 34 were confirmed to be Hispanic through self-reporting. The Wassel classification was applied using the definitions of seven types of radial polydactyly as described in the original article by Wassel in 1969. If the presentation of polydactyly did not match any of the seven types of polydactyly, then it was categorized as “unclassifiable.”

Results & Discussion

Our 34 Hispanic patients presented 39 cases of radial polydactyly for review. The literature demonstrates that Wassel subtype IV is the most commonly occurring, followed by type II and VII (Dijkman 2014). Our data demonstrated deviation from this trend as Type VII polydactyly occurred 28% of the time, followed by Type IV (23%), and then Type II (18%). Compared to existing literature, a considerable percentage of our Hispanic population was not able to be classified using the Wassel system, 18% compared to 6%.


Classification of cases of radial polydactyly plays an important role in the planning of surgical intervention, evaluation of clinical outcome, and communication among surgeons. This investigation demonstrated that strict application of definitions presented by the Wassel classification system may lead to a large percentage of cases being categorized as “unclassifiable.” It also showed a trend, though not statistically significant, toward a greater number type VII thumbs in the Hispanic population than previously reported in other populations.

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