Linguistic validation and cultural adaptation of Tamil version of oxford shoulder score

The Oxford Shoulder Score (OSS) is a well-established and extensively utilized shoulder score translated into Western and Asian languages for use in respective countries. Our study aimed to translate, cross-culturally adapt, and psychometrically validate the OSS in the Tamil language community.

The translation and cross-cultural adaptation were conducted according to previously established standards. We recruited 61 patients with degenerative or inflammatory shoulder pain presenting to a tertiary care hospital between January-August 2021. Patients were evaluated using the Tamil-OSS (OSS-T) and Constant-Murley scores (CMS). We assessed the understanding, acceptability, reproducibility, and reliability of the OSS-T. In addition, we evaluated the intra-observer and inter-observer reproducibility. We also evaluated the correlation of the OSS-T with another validated score namely the CMS.

The mean age of the patient included in the study was 43 (±12) years. Patients took an average of 8 (±2) minutes to complete the OSS form. Internal Consistency of the OSS-T was strong (Cronbach's alpha = 0.98). The intraclass coefficient was 0.963 (95 % CI 0.93-0.98, p < 0.001). We noted significant interobserver reliability (r = 0.963, p < 0.001). The Tamil OSS showed a strong significant correlation with the CMS (r = 0.82, p < 0.001) and original OSS (r = 0.98, p < 0.001). The OSS-T has a high level of convergent validity with CMS (p < 0.001). The 12 included translated questions in the OSS-T scored more than 0.95 from the subject experts for inclusion based on the three-point Likert scale.

This study indicated that the Tamil version of the OSS is a reliable and valid, self-reported questionnaire, which can be applied to patients with shoulder disorders. Furthermore, the very good psychometric properties of the OSS-T score would allow for its use in clinical practice in national and international research projects concerning Tamil-speaking patients.

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