Basic scientific studies have demonstrated positive effects of platelet-rich therapies, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF), on tendon repair. However, clinical evidence indicating improved prognosis is controversial. In this study, we aimed to determine whether augmentation of arthroscopic rotator cuff repair with PRP and PRF improves outcomes compared to arthroscopic repair alone.PubMed, Embase and Cochrane library databases were comprehensively searched for randomized controlled trials (RCTs) published until June 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. No language restriction was applied.The primary outcomes were the rate of repeat tears after arthroscopic rotator cuff repair (retear rate) and clinical function scores (Constant-Murley score, University of California, Los Angeles score), and the extracted data were assessed for quality. Statistical analyses were performed using Review manager 5.3, and P < 0.05 was considered statistically significant.Ten RCTs with 628 patients were included. The results showed that augmenting surgery with PRP reduces retear rates compared to surgery alone (risk ratio [RR] = 0.40, 95% confidence interval [CI] [0.23, 0.69], P = 0.001), whereas PRF has no effect on retear rates (P = 0.92). Regarding clinical function, PRP improves constant scores (mean difference [MD] = 2.03, 95% CI [0.13, 3.93], P = 0.04) and University of California, Los Angeles scores (MD = 1.30, 95% CI [0.36, 2.24], P = 0.007), whereas PRF only improves constant scores (MD = 3.93, 95% CI [1.50, 6.36], P = 0.002). However, these differences were small and below the minimum clinically important difference threshold.This study showed that compared to arthroscopic rotator cuff repair alone, the application of PRP in arthroscopic rotator cuff repair reduces retear rate and improves clinical function scores, whereas the application of PRF has no clinically meaningful benefit. The small number and heterogeneity of studies as well as methodological limitations and risk of bias limit confidence in the true effect. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.