Does graft thickness affect outcomes in massive rotator cuff repairs with on-lay and bridging graft augmentation? A systematic review and meta-analysis.

Abstract

<h4>Aims and objective</h4>To evaluate whether graft thickness influences functional outcomes and re-tear rates in massive rotator cuff repairs (RCRs) with graft augmentation, and to compare effectiveness of on-lay versus bridging/interposition techniques.<h4>Methods</h4>A systematic review was performed according to PRISMA guidelines. MEDLINE, Embase and CINAHL databases were searched between April 2006 and April 2025. Clinical studies reporting shoulder-specific functional outcomes scores and re-tear rates evaluating RCRs with graft augmentation (on-lay or bridging) using allografts, xenografts and synthetic grafts, as well as comparative studies with standard repair with minimum 12-months follow-up were included. Studies were stratified by graft thickness (≤2 mm vs >2 mm) and technique (on-lay vs bridging).<h4>Results</h4>Thirty-eight studies (<i>n</i> = 1761; 23 with grafts ≤2 mm, 15 with grafts >2 mm) with a mean follow-up of 34.2 ± 18.6 months were included. On-lay augmentation with grafts ≤2 mm yielded the greatest reduction in re-tear risk (OR 0.15; 95% CI: 0.05-0.49; <i>p</i> = 0.04) and lowest failure rate (8%). Bridging with ≤2 mm grafts reduced re-tear risk by 67% (RR 0.33; 95% CI: 0.20-0.55), while grafts >2 mm reduced risk by 55% (RR 0.45; 95% CI: 0.27-0.74). The pooled re-tear rate was 12% (95% CI: 9-15%). On-lay augmentation with grafts ≤2 mm significantly improved functional outcomes compared with standard repair (mean difference 9.39 points; 95% confidence interval 1.09-17.68; <i>p</i> = 0.03), whereas no significant difference was observed for grafts >2 mm (MD +4.28 points; 95% CI: 0.09-8.46; <i>p</i> = 0.05). Bridging with grafts ≤2 mm demonstrated the highest pooled mean constant scores (76.29; 95% CI: 69.56-83.68).<h4>Conclusion</h4>Both on-lay and bridging augmentation techniques significantly reduced re-tear rates compared with standard repair alone. Grafts ≤2 mm provided a greater reduction in re-tear risk with both techniques and showed a trend towards superior functional outcomes.