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.