Cross-Cultural Validity and Reliability of the Thai Version of the Simple Shoulder Test.

Background: The Simple Shoulder Test (SST) is a widely used patient-reported outcome measure for shoulder function. However, there is currently no version of the SST for the Thai population.

Purpose: To cross-culturally adapt and evaluate the reliability and validity of a Thai version of the SST (Thai SST) for patients with shoulder pathologies, using the Thai version of the American Shoulder and Elbow Surgeons (ASES) score as a comparison tool.

Study Design: Cohort study (diagnosis); Level of evidence, 3.

Methods: The Thai SST was developed using a standard translation and cross-cultural adaptation process. A total of 75 Thai patients, comprising 73 with rotator cuff tears, 3 with combined rotator cuff tear and secondary stiff shoulder, 2 with combined rotator cuff tear and biceps tendinitis, 1 with isolated adhesive capsulitis, and 1 with isolated long head biceps tendinopathy, completed the Thai SST and the Thai ASES score. The internal consistency, test-retest reliability, and construct validity of the Thai SST were assessed.

Results: The 75 participants consisted of 19 men and 56 women with a mean age of 63.16 ± 7.66 years. The Thai SST demonstrated a strong positive correlation with the Thai ASES ( = 0.714). The test-retest reliability for the Thai SST was good (intraclass correlation coefficient, 0.895). The Cronbach alpha of the Thai SST was 0.85, indicating good and acceptable internal consistency.

Conclusion: Our study demonstrated that the Thai SST had acceptable reliability and validity, making it a suitable patient-reported outcome measure for assessing shoulder function in Thai patients with shoulder problems. The Thai SST can be used to assess the effectiveness of interventions for these shoulder pathologies in Thai patients.