Measuring patient-reported outcomes in orthognathic surgery: Linguistic and psychometric validation of the Mandarin Chinese version of FACE-Q instrument

Background: Orthognathic surgery is useful for correction of dental malocclusion and improvement of facial appearance. The FACE-Q is a patient-reported outcome instrument for evaluation of surgical and psychosocial effect. The purposes of this study were to conduct a linguistic validation of all FACE-Q scales to Mandarin Chinese, to test the orthognathic surgeryrelated scales for reliability and validity, and to evaluate the effect of orthognathic surgery. Methods: All FACE-Q scales and checklists were translated from English to Mandarin Chinese according to international recommendations: forward translations, backward translation, and cognitive interviews. Psychometric testing of orthognathic surgery-related scales of translated version was administered to patients with facial deformities and history of orthognathic surgery (n = 53; 17 scales) or no history of orthognathic surgery (n = 44; 11 scales), and control subjects (n = 57; 11 scales). Results: All FACE- Q scales and checklists were linguistically validated into Mandarin Chinese. The contents were confirmed valid among Mandarin Chinese-speaking population. The FACE-Q scales had excellent internal consistency (Cronbach's alpha >0.70) and discriminated (p < 0.05) well between patients before and after orthognathic surgeries and normal subjects. Conclusions: This study discovered significant benefit of orthognathic surgery on improving facial appearance and psychosocial function, as compared with the non-surgical patients and normal controls.