Comparison of Functional Outcome Scores in Radial Polydactyly Robert R. Dijkman, MD, Christianne A. van Nieuwenhoven, MD, PhD, Ruud W. Selles, PhD, and Steven E.R. Hovius, MD, PhD Investigation performed at the Department of Plastic and Reconstructive Surgery and Hand Surgery, Rotterdam, the Netherlands Background: A wide range of outcome assessment systems have been used to describe the results and evaluate residual impairment after surgery for radial polydactyly. We conducted a study to determine which of these assessment systems should be considered superior for the most common types of radial polydactyly (types II and IV). Methods: Ten outcome assessment systems were selected. Three examiners independently evaluated thirty-seven patients, aged four to twenty-two years, with radial polydactyly. Patients completed two manual activity questionnaires. Interobserver reliability was determined with use of an intraclass correlation coefficient (ICC). Validity was assessed by correlating the results derived with the outcome assessment systems with functional visual analog scale (VAS), aesthetic VAS, and manual activity questionnaire scores. Results: Thirty-seven patients (forty-one hands with radial polydactyly) were evaluated. All patients were assessed by at least two examiners. Reliability was highest for the Japanese Society for Surgery of the Hand (JSSH), Cheng et al., and Tada et al. assessment systems (overall ICCs ‡ 0.70). The JSSH system had the highest overall correlations (r s ranging from 0.48 to 0.80 and 0.45 to 0.63) with functional and aesthetic VAS scores. No significant correlations were found between the outcome scores and the results of the manual activity questionnaires after an average follow-up time of 112 months. Conclusions: Interobserver reliability was highest for the JSSH classification, which also showed superior correlations with both examiner-rated and patient-rated VAS scores for functional and aesthetic outcome compared with the other nine assessment systems. The finding of a poor correlation between the outcome scores and the results of manual activity questionnaires is in agreement with findings in published literature. We recommend the JSSH assessment method for the scientific evaluation of the outcomes, in terms of body structure and function, of the treatment of radial polydactyly. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. R adial polydactyly is a relatively common and diverse con- genital hand difference 1 . Many reports have described the results and complications of the complex surgical treatment of radial polydactyly. The postoperative evaluation methods applied in these studies have ranged from mainly de- scriptive systems 2 to strict scoring forms 3 . Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the bio- medical arena that could be perceived to influence or have the po- tential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Con- flicts of Interest submitted by authors are always provided with the online version of the article. A commentary by Marybeth Ezaki, MD, is linked to the online version of this article at jbjs.org. Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors. 463 COPYRIGHT Ó 2014 BY THE J OURNAL OF BONE AND J OINT SURGERY,I NCORPORATED J Bone Joint Surg Am. 2014;96:463-70 d http://dx.doi.org/10.2106/JBJS.M.00067