Single- versus double-row repair for full-thickness rotator cuff tears using suture anchors. A systematic review and meta-analysis of basic biomechanical studies

Purpose: The purpose of this study was to perform a systematic review and meta-analysis comparing single- and double-row biomechanical studies to evaluate load to failure, mode of failure and gap formation. Materials and methods: A systematic review of MEDLINE, Embase, Scopus and Google Scholar was performed from 1990 through 2016. The inclusion criteria were: documentation of ultimate load to failure, failure modes and documentation of elongation or gap formation. Studies were excluded if the study protocol did not use human specimens. Publication bias was assessed by funnel plot and Egger’s test. The risk of bias was established using the Cochrane Collaboration’s risk of bias tool. Heterogeneity was assessed using χ ² and I ₂ statistic. Results: Eight studies were included. The funnel plot was asymmetric suggesting publication bias, which was confirmed by Egger’s test (p = 0.04). The pooled estimate for load to failure demonstrated significant differences (SMD 1.228, 95% CI: 0.55–5.226, p = 0.006, I ₂  = 60.47%), favouring double-row repair. There were no differences for failure modes. The pooled estimate for elongation/gap formation demonstrated significant differences (SMD 0.783, 95% CI: 0.169–1.398, p = 0.012, I ₂  = 58.8%), favouring double-row repair. Conclusion: The results of this systematic review and meta-analysis suggest that double-row repair is able to tolerate a significantly greater load to failure. Gap formation was also significantly lower in the double-row repair group, but both of these findings should be interpreted with caution because of the inherent interstudy heterogeneity. Level of evidence: Systematic review and meta-analysis.