Translation and cross-cultural adaptation of the Shoulder Pain and Disability Index (SPADI) into Chinese

The aim of this study is to translate and cross-culturally adapt the Shoulder Pain and Disability Index (SPADI) for the Chinese language, and to evaluate its psychometric properties. The SPADI was translated and cross-culturally adapted for the Chinese language according to established guidelines. Participants completed the SPADI questionnaire, a visual analogue scale (VAS), and the 36-item short form health survey (SF-36), and were assessed using the Constant-Murley shoulder outcome score. Exploratory factor analysis was used to examine the latent dimensions, and Cronbach's α to measure internal consistency. The construct validity was tested by Pearson correlations with the Constant-Murley score, VAS, and SF-36, while intraclass correlation coefficient (ICC) was calculated to assess the test-retest reliability of the Chinese SPADI. The floor and ceiling effects were calculated by the proportion of participants who obtained the highest (100) and lowest (0) possible score on the baseline questionnaires. We tested its psychometric properties with 120 participants (55 men and 65 women, age: 55.64 ± 9.49 years, duration: 62.75 ± 15.96 weeks) with shoulder pain. And 58 participants completed the SPADI again within 7 days of the first completion to test the test-retest reliability. The Chinese version of the SPADI displayed high internal consistency (Cronbach's α = 0.91). Test-retest reliability was high with an intraclass correlation coefficient of 0.87. A very good correlation was observed between the SPADI and the Constant-Murley score (r = 0.69), a good correlation between the SPADI and the VAS (r = 0.40), and a fair correlation between the SPADI and the SF-36 (r = 0.36). There were no significant floor and ceiling effects in the total Chinese SPADI. The Chinese version of the SPADI is a valid and reliable tool that could be used to measure the degree of pain and disability in Chinese-speaking patients with shoulder pain.