BACKGROUND In this systematic review and meta-analysis, we evaluated ultrasound (US)-guided injections of platelet-rich plasma (PRP) as conservative treatment of tendinopathies. MATERIALS AND METHODS We searched MEDLINE, EMBASE, SCOPUS, OVID, and the Cochrane Library to identify randomized controlled trials (RCT) on the use of US-guided PRP for tendinopathies. RESULTS We found 33 RCT (2,025 subjects) that met our inclusion criteria:
8 in lateral epicondylitis, 5 in plantar fasciitis, 5 in Achilles tendinopathy, 7 in rotator cuff tendinopathy, 3 in patellar tendinopathy and 5 in carpal tunnel syndrome. PRP, given as a single injection (20 trials) or multiple injections (13 trials), was compared to US-guided injection of steroids, saline, autologous whole blood, local anesthetic, dry needling, prolotherapy, bone marrow mesenchymal stem cells, or with non-injective interventions. The outcomes more commonly reported included pain and functional measures, subgrouped as in the short-term (<3 months from the intervention), medium-term (3 to 6 months) or long-term (≥12 months). No clear between-group differences in these outcomes were observed in patients with lateral epicondylitis, plantar fasciitis, or Achilles, rotator cuff or patellar tendinopathy. In patients with carpal tunnel syndrome, visual analog scale scores for pain at 3 and 6 months and Boston Carpal Tunnel Questionnaire severity scores at 1, 3 and 6 months were significantly lower in PRP recipients than in controls. The certainty of evidence of all these comparisons was graded as low or very low due to risk of bias, imprecision and/or inconsistency. Pain at the injection site was more common among PRP recipients than among controls receiving other US-guided injections. DISCUSSION In patients with tendinopathies, a trend towards pain reduction and functional improvement from baseline was observed after US-guided PRP injection, but in the majority of the comparisons, the effect size was comparable to that observed in control groups.