The development and validation of an appraisal method for rotator cuff disorders: The Korean Shoulder Scoring System

Hypothesis: The purpose of this study was to develop and validate a disease-specific appraisal method for patients with rotator cuff disorders. The Korean Shoulder Scoring System (KSS) includes 5 domains totalling 100 points: function, 30 points; pain, 20; satisfaction, 10; range of motion, 20; and muscle power, consisting of strength, 10; and endurance, 10. Method: The KSS was used to evaluate clinical outcomes of 430 patients with rotator cuff disorder for a period of 6 months postoperatively. Result: The KSS had an acceptable level of internal consistency (α = 0.840). The KSS scores also correlated strongly with the Constant scores (r = 0.802), but less so with the American Shoulder and Elbow Surgeons scores (r = 0.602) and the University of California Los Angeles shoulder scores (r = 0.573). A large effect size (r = 1.234) and a standardized response mean (r = 1.317) for KSS were evident at 6 months postoperatively. Conclusion: The KSS is a useful measurement tool that combines subjective and objective evaluations for shoulder function related to rotator cuff disorders.