BACKGROUND AND OBJECTIVES: It has been proposed that some individuals with musculoskeletal pain may perceive themselves as victims of injustice. Perception of injustice can have a significant impact on several pain-related outcomes, major depressive symptoms, disabilities, and absenteeism. The objective of this study consisted of a transcultural adaptation of the original instrument in English, Injustice Experience Questionnaire into a final version to be used in Brazil. METHODS: The whole translation process consisted of translation, back-translation and the review by a committee of experts. The pre-test was applied to 90 participants (41 participants with chronic musculoskeletal pain). For the psychometric analysis, the translated version was applied to 120 participants with chronic musculoskeletal pain. The internal consistency was verified by the Cronbach's alpha coefficient, and the construct validity was analyzed using factorial exploratory analysis. RESULTS: After the conclusion of the pre-test, there were no difficulties in understanding the translated questionnaire by more than 20% of the sample. The Cronbach alpha calculation for the 12 items of the Injustice Experience Questionnaire/Port-BR was 0.86 [CI (95%) = 0.83 to 0.90; p<0.001]. CONCLUSION: The questionnaire's Portuguese version proved to be easily understandable showing good semantic validation. Nevertheless, further studies should address other psychometric characteristics of this instrument.

BACKGROUND AND OBJECTIVES:To date, there is no information on the perception of injustice in patients with musculoskeletal pain in Brazil. The present study evaluated the perception of injustice in individuals with chronic musculoskeletal pain and its association with pain intensity. METHODS: Information regarding the participants' identification and experience of injustice was gathered using the Injustice Experience Questionnaire. Pain intensity data was collected through the numerical pain rating scale. The descriptive data analysis was performed. Pearson's correlation test was used to verify the association between pain intensity and perceived injustice. The level of significance adopted was alpha=95%. RESULTS:The study was composed of 110 patients with chronic musculoskeletal pain being 94 women with a mean age of 62.9±14.9 years. The mean perceived injustice was 19.45±11.68 out of a total of 48 points. The mean pain intensity was 6.39±2.48. The correlation between pain intensity and perceived injustice was r=0.23 [CI (95%) = 0.04 to 0.40; p=0.008]. The correlation between blame and unfairness and pain intensity was r=0.16 (p=0.08). For the severity and irreparability domain the correlation was r=0.28 (p=0.003).