The University of California-Los Angeles (UCLA) shoulder scale: translation, reliability and validation of a Thai version of UCLA shoulder scale in rotator cuff tear patients

BACKGROUND: UCLA Shoulder Scale is a useful evaluation tool to assess the functional outcome of shoulder after treatments. It has been translated into several languages. The objectives of this study were to translate UCLA Shoulder Scale into Thai language and validate the translated version in patients with rotator cuff tear. METHODS: This study consists of 2 phases: 1) Development of the Thai version of UCLA Shoulder Scale and 2) Validation of the translated version. The UCLA Shoulder Scale was translated into Thai according to the international guideline. Seventy-eight subjects with a mean age of 71 ± 11.5 took part in the study. All had shoulder pain and rotator cuff tear according to MRI from 2019 to 2020. Four patients were excluded due to incomplete questionnaires. The data from 21 patients whose symptoms in shoulder joint had not changed within 14 days were analyzed with the UCLA Shoulder Scale test-retest using intraclass correlation (ICC), Standard Error of Measurement (SEM) and Minimal Detectable Change (MDC). The Thai version of UCLA Shoulder Scale was compared to the validated Thai versions of American Shoulder and Elbow Surgeons (ASES), Western Ontario Rotator Cuff (WORC) and Shortened version of The Disability of the Arm, Shoulder and Hand (QuickDASH) shoulder scores. RESULTS: Thai version of UCLA Shoulder Scale was developed following the guideline. Moderate to strong correlations were found using Spearman’s correlation coefficient between pain, function and total score of Thai version of UCLA Shoulder Scale. The reliability of total UCLA Shoulder Scale was excellent (ICC = 0.99, 95% CI 0.97–1.00), whereas agreement assessed with SEM and MDC (0.18 and 0.50 respectively) demonstrated a positive rating. The validity analysis of total UCLA Shoulder Scale (Thai version) showed moderate to strong correlations with total ASES, total WORC and QuickDASH (Thai versions). The Thai version of UCLA Shoulder Scale showed no floor and ceiling effects from the results. CONCLUSION: The Thai version of UCLA Shoulder Scale is a reliable and valid tool for assessing the function and disability of the shoulder in Thai patients who have rotator cuff tear.