Comparison of Structural Integrity and Functional Outcome Between Delaminated and Nondelaminated Rotator Cuff Tears After En Masse Arthroscopic Repair: A Retrospective Cohort Study With Propensity Score Matching

Background: Arthroscopic repair of delaminated rotator cuff tears (RCTs) has shown poor prognoses. Despite the importance of delaminated tears, only a few studies have compared delaminated and nondelaminated tears. Purpose: This study aimed to compare the clinical outcomes and structural integrity after en masse arthroscopic rotator cuff repair between delaminated and nondelaminated RCTs and to evaluate whether infraspinatus tendon involvement affects the prognosis for delaminated tears after arthroscopic cuff repair, through use of propensity score matching for precise comparison. Study Design: Cohort study; Level of evidence, 3. Methods: This study included 180 consecutive patients with medium- or large-sized RCTs who had an arthroscopic rotator cuff repair with a minimum 2-year follow-up, of whom 57 and 123 had delaminated tears (group 1) and nondelaminated tears (group 2), respectively. The en masse repair technique using a single-row or transosseous-equivalent double-row suture-bridge technique was used for of all the delaminated cases. Preoperative and postoperative visual analog scale pain scores, shoulder active range of motion, American Shoulder and Elbow Surgeons (ASES) scores, and Constant scores were assessed. Magnetic resonance imaging was performed at least 24 months postoperatively to identify retear of the repaired rotator cuffs. After propensity score matching, 32 cases in both groups were successfully matched, and the clinical and radiological results were analyzed. Results: Before propensity score matching, postoperative clinical outcomes were improved, showing no significant differences between the groups, excluding forward elevation (P = .011). Groups 1 and 2 had 17 (29.8%) and 11 retear cases (8.9%), respectively (P < .001). After propensity score matching, only the ASES score (72.5 vs 77.1) showed a significant superiority in group 2 (P = .038). Propensity-matched groups 1 and 2 had 8 (25.0%) and 2 (6.3%) retear cases, respectively (P = .034). No significant difference was found in structural integrity depending on whether the RCT included the infraspinatus tendon (IST). The odds ratio for retear of the delaminated tears, including IST, was 5.5 (95% confidence interval, 1.0-30.0, P = .038). Conclusion: Delaminated RCT was a negative prognostic factor of structural integrity after repair and could affect the functional outcome. However, whether IST tear was involved had no effect on the prognosis after repair.