To validate the Shoulder Stiffness Scale (SSS) in a large cohort of patients undergoing arthroscopic rotator cuff repair (ARCR) by examining its change over time, internal consistency, and construct validity.
Approach:
Study Design: A prospective, multicenter observational study (ARCR_Pred) involving 973 primary ARCR patients was conducted, with follow-up assessments at 6 weeks, 6 months, 12 months, and 24 months.
SSS Development: The SSS was developed to specifically assess shoulder stiffness, combining pain, subjective range of motion (ROM) limitation, and objective ROM restriction.
Data Collection: Patient demographics, clinical examination, and patient-reported outcomes were documented at baseline and follow-ups.
Statistical Analysis: Data were analyzed using descriptive statistics, Friedman’s ANOVA, repeated-measures ANOVA, and Cronbach’s alpha for internal consistency.
Key Findings:
The SSS demonstrated significant changes over time, indicating its sensitivity to detect variations in shoulder stiffness.
Internal consistency of the SSS was acceptable with a Cronbach’s alpha above 0.70.
The SSS correlated well with established shoulder scores such as the Constant Score, Oxford Shoulder Score, and Subjective Shoulder Value.
Interpretation:
The SSS is a valid tool for monitoring shoulder stiffness post-ARCR, providing a focused assessment that is distinct from broader shoulder function scores.
Limitations:
The study excluded patients with symptomatic concomitant pathology that could confound pain or ROM assessment.
Variations in postoperative rehabilitation protocols across centers may affect outcomes.
Conclusion:
The SSS is a reliable and valid instrument for assessing shoulder stiffness following arthroscopic rotator cuff surgery, aiding in the evaluation of postoperative recovery.
