INTRODUCTION: Shoulder instability is a common problem that usually affects patients on their second or third decade of life and athletes who practice throwing or contact sports. Its consequences are pain, decrease of activity level and general decrease in the quality of life. Many treatments have been used to the different types of instability; however, there are few instruments of evaluation that prove their efficacy. In order to apply evaluation measures in health used and developed for another idiom, it is necessary to do the transcultural equivalency, being unnecessary the creation and validation of another instrument that evaluates the condition under interest. The objective of this study was to do the translation and cultural adaptation of the WOSI scale (The Western Ontario Shoulder Instability Index) to Brazilian Portuguese. Materials and METHODS: The applied protocol consisted of: 1) Preparation, 2) Translation, 3) Back-Translation, 4) Cognitive Interrogatory and 5) Information Report. After the conclusion of the translation and back-translation, the versions were sent to the original WOSI authors who approved the continuation of the study. The Portuguese version was applied in 35 patients with shoulder instability to verify the instrument's level of comprehension. The final Brazilian WOSI version was concluded after reaching less than 15% of "no comprehension" in each item. To analyze the variables, descriptive statistics was applied. RESULTS: To obtain the cultural equivalency, modifications and terms alterations suggested by the patients for the items "no comprehension" were done. CONCLUSION: After the translation and cultural adaptation of the scale, the WOSI Portuguese version was accomplished.
instability; questionnaires; translation; quality of life
