Purpose
To determine the various Minimal Clinically Important Difference (MCID) for Constant-Murley score (CMS), University of California Los Angeles (UCLA) shoulder score, and Oxford Shoulder Scores (OSS) after arthroscopic rotator cuff (RC) repairs.
Methods
Between 2010 and 2015, patients who underwent unilateral arthroscopic RC repair by a single surgeon were prospectively followed up and assessed pre-operatively, and at 12- and 24-month post-operatively for CMS, UCLA, OSS, satisfaction, and expectation fulfilment. Anchor-based approach with 2 external indicators (satisfaction and expectation fulfilment) were used. MCID for CMS, UCLA and OSS at 12-month and 24-month was determined using simple linear regression according to patient satisfaction and expectation fulfilment.
Results
306 patients were analysed at 12-month and 222 at 24-month. The mean age of patients at 12-month and 24-month were 60.2 ±10.3 years and 60.3 ± 10.0 years respectively. There were 139 male and 167 female patients in the 12-month group and 101 male and 121 female patients in the 24-month group.
The following MCID were identified:
At 12-month:
CMS 6.7 (95% CI 4.5-8.9), UCLA 3.0 (95% CI 2.4-3.7), OSS 3.3 (95% CI 2.1-4.6)
At 24-month:
CMS 6.3 (95% CI 3.6-9.1), UCLA 2.9 (95% CI 2-3.7), OSS 2.7 (95% CI 2.1-3.4)
The MCID identified with the two anchor questions and between the two follow-up time points were similar. Combining the results of both follow-up and taking the higher value as the minimal score required, the MCID necessary to constitute a significant change in patient’s perceived outcome is 6.7 for CMS, 3.0 for UCLA, and 3.3 for OSS.
Conclusions
CMS, UCLA, and OSS are valid tools for calculation of MCID after arthroscopic RC repair and the various MCID calculated could be used as a benchmark for interpretation of these scores and serve as a tool to power future comparative studies.