Effectiveness of Platelet-Rich Plasma Injection in Rotator Cuff Tendinopathy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: To investigate the effectiveness of platelet-rich plasma (PRP) injection among patients with rotator cuff tendinopathy in comparison with sham injection, no injection, or physiotherapy alone. Methods: From the earliest records to November 1, 2018, all published or unpublished randomized controlled trial (RCTs) comparing PRP injection with a control group (sham injection, no injection, or physiotherapy alone) in patients with rotator cuff tendinopathy were included. Eligible trials were included from the search results of electronic databases including PubMed, EMBASE, Scopus, The Cochrane Library, as well as the bibliographies of relevant trials. Five RCTs were enrolled in our meta-analysis. Two authors independently assessed the quality of RCTs with the Cochrane risk of bias tool. We designated pain reduction as the primary outcome and functional improvement as the secondary outcome. Standardized mean difference (SMD) was applied for random-effect meta-analysis. Results: In the short term (3-6 weeks) and medium term (12 weeks), the effectiveness of PRP injection and control group was indistinguishable in terms of both outcomes (pain reduction and functional improvement). Nevertheless, PRP injection led to significant long-term (>24 weeks) pain relief (SMD: 0.42, 95% confidence interval (CI): 0.12-0.72, without heterogeneity). For functional improvement in the long term, PRP injection was not more effective than the control group (SMD: 1.20, 95% CI: -0.20-2.59, with heterogeneity). Conclusions: PRP injection may provide benefit over the control group (sham injection, no injection, or physiotherapy alone) in reducing pain at long-term follow-up for patients with rotator cuff tendinopathy.