Delamination of rotator cuff tears impairs healing after repair: a systematic review and meta-analysis.

PURPOSE: To compare the clinical outcomes and retear rates after rotator cuff repair (RCR) between delaminated and non-delaminated tears. METHODS: This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines using the PubMed, Cochrane Library, the Web of Science and Embase databases. Only articles on arthroscopic RCR with clinical outcome scores and data on the number of rotator cuff retears and complete healing were included. This study's relevant data were extracted and statistically analyzed. The methodological index for nonrandomized studies was used to assess the risk of bias in the included studies. After conducting a heterogeneity test and sensitivity analysis to determine whether the samples were heterogeneous, the study also detected publication bias. A sub-group test was used to evaluate the influences of the imaging follow-up period on retear rates. RESULTS: Ten eligible articles were identified with 2,061 patients (925 in the delaminated group and 1,136 in the non-delaminated group). The meta-analysis demonstrated that delamination was significantly associated with higher retear rates (P = 0.026; odds ratio = 1.873, 95% confidence interval 1.079-3.252; I2 = 51.6%) with an imaging follow-up period of > 1 year and lower rates of complete healing (P = 0.036; odds ratio = 0.659, 95% confidence interval 0.446-0.973; I2 = 9.0%) in patients after rotator cuff repair. However, no significant differences were observed between the two groups based on American Shoulder and Elbow Surgeons score, Constant score, visual analog scale score, external rotation, internal rotation, or forward elevation. CONCLUSIONS: This meta-analysis found that delamination was significantly associated with higher retear rates with imaging follow-up period of > 1 year, and lower rates of complete healing. In addition, the preoperative and postoperative clinical scores and shoulder joint range of motion were similar between patients with delaminated and non-delaminated tears. LEVEL OF EVIDENCE: Level IV.