Estimating the minimal clinically important difference of shoulder functional scores after arthroscopic rotator cuff repair: a prospective study

INTRODUCTION: The minimal clinically important difference (MCID) is a valuable tool for patient-based outcome analysis, for which limited data is available in the literature, especially after arthroscopic rotator cuff repair (ARCR). Although several studies have reported MCID after ARCR, few have studied the impact of various clinical factors such as Diabetes, pseudoparalysis, type of cuff repair, and retear over MCID. This study attempts to determine the MCID in shoulder functional scores after ARCR and the impact of various factors on MCID. METHODS: 144 patients undergoing ARCR were prospectively evaluated at six and 12 months by ASES and UCLA scores. MCID for American Shoulder and Elbow Surgeons (ASES) and the University of California and Los Angeles (UCLA) scores were calculated using an anchor-based and distribution-based approach. MCID was also calculated for diabetic and non-diabetic patients, smokers vs. non-smokers, presence or absence of pseudoparalysis, type of cuff repair (single row vs. suture bridge), and presence of retears. Uni- and multivariate analysis was performed to identify factors affecting the MCID of both scores. RESULTS: Mean MCID for ASES score was 13.3 and 16.6 using an anchor-based and distribution-based approach, respectively. For the UCLA score, the mean MCID was 10.0 and 12.6 by anchor-based and 12.6 by distribution-based approach, respectively. Patients with higher pre-operative ASES scores demonstrated lower MCID values. No significant difference was observed in MCID scores of diabetic vs. non-diabetic patients, smoker vs. non-smoker, patients with or without pseudoparalysis, and type of cuff repair. The age, gender, and presence of retear did not affect MCID values. CONCLUSION: This study establishes the MCID values of ASES and UCLA scores for rotator cuff repair by anchor and distribution methods. No patient or surgical factors appear to affect the MCID except pre-operative ASES scores. STUDY DESIGN: Prospective cohort, Level II.