Persian Version of the Modified Constant Score in Overhead Athletes: A Reliability and Validation Study.

Context: Shoulder impingement syndrome (SIS) is the most common shoulder injury among overhead athletes. The Constant score (CS) is a combined scoring system to evaluate functional status of the shoulder in patients with shoulder pain.

Design: Cross-sectional study.

Methods: Cultural adaptation of the Persian version of CS was conducted using Beaton's guideline. Sixty-three overhead athletes (23.57 [7.50] y old) with SIS completed the final version for psychometric assessment. After 5 to 7 days, a group of 33 patients completed the Persian CS again to assess test-retest reliability. Internal consistency, floor/ceiling effects, and item-total correlation were evaluated in patients with SIS. Concurrent validity was assessed through comparison with the disability of the arm, shoulder, and hand questionnaire scores. Twenty-five healthy athletes (31.80 [7.32] y old) participated for determining discriminant validity.

Results: The Persian CS demonstrated good test-retest reliability, with subjective and objective intraclass correlation coefficients of .79 and .80, respectively. The internal consistency was satisfactory (Cronbach alpha = .74). No ceiling or floor effects were noted. The Pearson correlation coefficient between CS and disability questionnaire was -.68. The mean total score for patients was 67.02, while for the healthy group was 96.99 (P = .000). The standard error of measurement was 1.51 for patients and 0.7 for healthy group. The smallest detectable change was 16.95 for patients and 5.71 for healthy group.

Conclusion: The translation and cross-cultural adaptation of CS into Persian were successful. The Persian version demonstrates sufficient reliability and validity to evaluate shoulder function in overhead athletes with SIS.