Efficacy of intra-articular platelet-rich plasma compared with placebo in knee osteoarthritis: a systematic review and meta-analysis

Our primary aim was to evaluate the efficacy on pain and function of intra-articular platelet-rich plasma (PRP) injection in knee osteoarthritis (KOA) compared with intra-articular saline solution injection. A search for randomized controlled studies (RCTs) using intra-articular platelet-rich plasma injection compared with intra-articular saline solution injection up to August 2024 (PROSPERO registration number: CRD42022311893) was undertaken in publication databases. Studies that reported pain and function evaluation with visual analogue scale (VAS) and/or WOMAC, size sample, study date and location were included. A meta-analysis was conducted to estimate the efficacy on pain and function of intra-articular platelet-rich plasma injection. We identified 11 RCTs including 1616 patients (849 on PRP, 767 on placebo) conducted in 7 countries, with 56% of patients being women. The mean age was 56.9years. VAS analysis at 3 and 6months after intervention was in favor of PRP use (respective mean difference MD -1.1 95% CI: -1.8; -0.4 and -2.0 95% CI: -2.8; -1.2) but with high heterogeneity, whereas no efficacy was shown at 12months. The variation of total WOMAC at 3months after intervention was in favor of PRP use (MD -12.9 95% CI: -20.5; -5.3), but no efficacy was shown at 6 and 12months. We have found a weak efficacy of PRP in knee osteoarthritis, up to 6months after intervention, so the clinical relevance of PRP use is debatable.