Graft Augmentation of Rotator Cuff Repair Improves Load to Failure But Does Not Affect Stiffness or Gap Formation: A Meta-analysis of Biomechanical Studies

Abstract

The purpose of this review was to examine the biomechanical properties of RCR-G with regard to ultimate load to failure, gap displacement, and stiffness. A systematic review was performed by searching PubMed, the Cochrane library, and Embase using PRISMA guidelines to identify studies that analyzed the biomechanical properties of RCR with graft augmentation. The search string implemented utilized the concepts "rotator cuff" and "graft," and "biomechanical" OR "cadaver." Meta-analysis was performed to provide a quantitative comparison of the two techniques. Primary outcome measures were ultimate load to failure (N), gap displacement (mm), and stiffness (N/mm). Initial search yielded 1,493 articles for review. Following screening for inclusion criteria, eight studies were included in the meta-analysis, including a total of 191 cadaveric specimens (106 RCR-G, 85 RCR). The pooled analysis from six studies reporting on ultimate load to failure revealed a statistically significant difference in favor of RCR-G compared to RCR (p < 0.001). Pooled analysis from six studies reporting on gap displacement failed to reveal a difference between RCR-G and RCR (p = 0.719). Pooled analysis from four studies reporting on stiffness failed to reveal a difference between RCR-G and RCR (p = 0.842). Graft augmentation of RCR in vitro resulted in significantly increased ultimate load to failure, with no influence on gap formation or stiffness. The biomechanical advantage of RCR with graft augmentation demonstrated via increased ultimate load to failure in cadaveric studies may provide an explanation for the decreased RCR retear rates and improved patient reported outcomes reported in the clinical literature regarding graft augmentation.