Tear Size and Stiffness Are Important Predictors of Retear: An Assessment of Factors Associated with Repair Integrity at 6 Months in 1,526 Rotator Cuff Repairs

This study aimed to identify whether early postoperative shoulder stiffness is associated with improved healing following rotator cuff repair, and if so, how this factor might interact with other factors known to affect rotator cuff repair integrity. METHODS: We conducted a retrospective analysis of prospectively collected data from 1,526 primary arthroscopic rotator cuff repairs. Six-week range of motion was assessed to determine shoulder stiffness, and repair integrity was evaluated at 6 months by ultrasound. Multiple logistic regression analysis was used to identify variables that affected retear, and receiver operating characteristic (ROC) curve analysis was used to evaluate predictive thresholds for retear. RESULTS: Tear-size area was the most accurate predictor of retear (area under the curve [AUC] = 0.77; 95% confidence interval [CI] = 0.72 to 0.81), followed by 6-week passive external rotation (AUC = 0.67; 95% CI = 0.63 to 0.72), 6-week passive forward flexion (AUC = 0.67; 95% CI = 0.62 to 0.72), age (AUC = 0.65; 95% CI = 0.60 to 0.70), tear type (partial-thickness versus full-thickness) (AUC = 0.65; 95% CI = 0.61 to 0.69), and hospital type (public versus private) (AUC = 0.43; 95% CI = 0.37 to 0.49). Patients with smaller tears, reduced 6-week passive external rotation, reduced 6-week passive forward flexion, younger age, partial-thickness tears, and operations performed in a private day surgery or hospital setting were more likely to have an intact rotator cuff repair at 6 months. The AUC of this curve was 0.84 (95% CI = 0.80 to 0.87), which indicates that this combination of factors can accurately predict 84% of retears. Reduced range of motion at 6 weeks was associated with improved repair integrity for patients with tears of >1 to 6 cm(2); however, this effect was less pronounced in tears of ≤1 cm(2) or >6 cm(2). CONCLUSIONS: Early postoperative stiffness following arthroscopic single-row, inverted-mattress rotator cuff repair at 6 weeks was associated with an intact repair at 6 months. The protective effects of postoperative stiffness and tear size were additive. The chance of retear in patients with a tear of ≤1 cm(2) and external rotation of ≤27° at 6 weeks was 1%, while those with tears of >6 cm(2) and external rotation of >27° had a 40% chance. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.