Responsiveness of the Persian version of oxford shoulder score in subjects with shoulder pain: brief report

Background: Oxford Shoulder Score (OSS) is a specific questionnaire for the assessment of pain and function in subjects with shoulder pain. The reliability and validity of the Persian version of this questionnaire have been shown previously. But its responsiveness has not been investigated yet. This study aimed to determine the Persian OSS responsiveness in subjects with shoulder pain. Methods: This was a prospective cohort study design conducted in the Physiotherapy Clinic, School of Rehabilitation, Tehran University of Medical Sciences in 2018.  Thirty-one subjects with shoulder pain (20 females and 11 males) with a mean age of 50±15.3 participated in this study. They completed the Persian OSS, Disability of Arm, Shoulder & Hand (DASH) questionnaire, and Visual Analog Scale (VAS) before and after 10 physiotherapy sessions. After the 10th session, the Global Rating of Change (GRC) was also completed. The statistical analysis included the Effect Size (ES), Standardized Response Mean (SRM), and the Spearman or Pearson correlation coefficients. Results: The results showed that the ES and SRM of the Persian OSS were 1.73 and 1.79, respectively. The correlation between the Persian OSS and the VAS scores was 0.69 and between the Persian OSS and the DASH scores was 0.89. The correlation between the Persian OSS changes and GRC was not statistically significant (r=0.25, P=0.18). However, a significant moderate correlation was identified between the VAS and DASH with the GRC scores (r=0.43, r=0.42, respectively).  Conclusion: The Persian OSS has internal and external responsiveness for the assessment of subjects with shoulder pain. The Persian OSS, as a responsive instrument, can be used to investigate the effectiveness of interventions in the clinical settings and research to detect the changes in patients with shoulder pain. Further study with larger sample of patients with shoulder pain is warranted to confirm the findings and to estimate the minimally clinically important change.