Zurich Appearance Score for Hands: Development and Validation of an Instrument for Assessing Hand Appearance in Congenital Upper Limb Differences.

PURPOSE: The appearance of the hand is relevant to individual activity and participation. Improving appearance is often one of the essential goals of hand surgery. The aim of this study was to describe and validate an instrument for quantitatively assessing hand appearance in congenital upper limb differences (CULD). METHODS: The Zurich Appearance Score for Hands (ZASH) was developed as a summed score of 6 items: 1 for overall appearance and 5 specific items for the skin, proportions of the hand, the number of digits, the shape of fingers and the thumb, and the position of the thumb. Each item can be rated on an 11-point Likert scale. Here, 448 participants (age, 14-83 years) were asked to rate the images of 17 hands, including standardized 3-dimensional photorealistic computer graphics and photographs of children's hands with or without CULDs, some after surgical correction. The sociodemographic characteristics of the participants were measured using a short questionnaire. RESULTS: The ZASH score for all CULDs was significantly lower than the ZASH score for normal hands. Correlations for overall appearance and the ZASH score were high (r = 0.77-0.87). The internal consistency of all ZASH scores was good to excellent (Cronbach α = 0.82-0.94). The test-retest reliability in a subgroup of 54 participants was good (r = 0.53-0.79). The interrater reliability of the ZASH score was moderate (intraclass correlation = 0.47). CONCLUSIONS: The ZASH is a valid and moderately reliable instrument for assessing hand appearance in children with CULDs. CLINICAL RELEVANCE: Achieving the best possible appearance is the one of the most relevant goals of hand surgery. Assessment with validated instruments provides evidence on how to approach this goal. Further studies may clarify whether the ZASH can be recommended for all hand conditions and to what extent observers' sociocultural and professional backgrounds affect perception.