Background: Recent literature has focused on correlating statistically significant changes in outcome measures with clinically significant outcomes (CSOs). CSO benchmarks are being established for arthroscopic rotator cuff repair (RCR), but more remains to be defined about them.
Purpose: To define the time-dependent nature of the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and Patient Acceptable Symptomatic State (PASS) after RCR and to define what factors affect this time to CSO achievement.
Study design: Case series; Level of evidence, 4.
Methods: An institutional registry was queried for patients who underwent arthroscopic RCR between 2014 and 2016 and completed preoperative, 6-month, 1-year, and 2-year patient-reported outcome measures (PROMs). Threshold values for MCID, SCB, and PASS were obtained from previous literature for the American Shoulder and Elbow Surgeons score (ASES), Single Assessment Numeric Evaluation (SANE), and subjective Constant score. The time in which patients achieved MCID, SCB, and PASS was calculated using Kaplan-Meier analysis. A Cox multivariate regression model was used to identify variables correlated with earlier or later achievement of CSOs.
Results: A total of 203 patients with an average age of 56.19 ± 9.96 years and average body mass index was 30.29 ± 6.49 were included. The time of mean achievement of MCID, SCB, and PASS for ASES was 5.77 ± 1.79 months, 6.22 ± 2.85 months, and 7.23 ± 3.81 months, respectively. The time of mean achievement of MCID, SCB, and PASS for SANE was 6.25 ± 2.42 months, 7.05 ± 4.10 months, and 9.26 ± 5.89 months, respectively. The time of mean achievement of MCID, SCB, and PASS for Constant was 6.94 ± 3.85 months, 7.13 ± 4.13 months, and 8.66 ± 5.46 months, respectively. Patients with dominant-sided surgery (hazard ratio [HR], 1.363; 95% CI, 1.065-1.745; P = .014) achieved CSOs earlier on ASES, while patients with workers' compensation status (HR, 0.752; 95% CI, 0.592-0.955; P = .019), who were current smokers (HR, 0.323; 95% CI, 0.119-0.882; P = .028), and with concomitant biceps tenodesis (HR, 0.763; 95% CI, 0.607-0.959; P = .021) achieved CSOs on ASES at later timepoints. Patients with distal clavicle excision (HR, 1.484; 95% CI, 1.028-2.143; P = .035) achieved CSOs earlier on SANE. Patients with distal clavicle excision (HR, 1.689; 95% CI, 1.183-2.411, P = .004) achieved CSOs earlier on Constant, while patients with workers' compensation insurance status (HR, 0.671; 95% CI, 0.506-0.891; P = .006) and partial-thickness tears (HR, 0.410; 95% CI, 0.250-0.671; P < .001) achieved CSOs later on Constant. Greater preoperative score was associated with delayed achievement of CSOs for ASES, SANE (HR, 0.993; 95% CI, 0.987-0.999; P = .020), and Constant (HR, 0.941; 95% CI, 0.928-0.962; P < .001).
Conclusion: A majority of patients achieved MCID by 6 months after surgery. Dominant-sided surgery and concomitant distal clavicle excision resulted in faster CSO achievement, while workers' compensation status, concomitant biceps tenodesis, current smoking, partial-thickness rotator cuff tears, and higher preoperative PROMs resulted in delayed CSO achievement.
Keywords: Patient Acceptable Symptomatic State; arthroscopic rotator cuff repair; minimal clinically important difference; shoulder; substantial clinical benefit; time to achieve clinical significance.