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

Objectives: 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.

Methods: A search for randomized controlled studies (RCTs) using intra articular platelet-rich plasma injection compared with intra articular saline solution injection up to November 2022 (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.

Results: 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 56.9 years. VAS analysis at 3 and 6 months 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 12 months. The variation of total WOMAC at 3 months 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 12 months.

Conclusion: We have found a weak efficacy of PRP in knee osteoarthritis, up to 6 months after intervention, so the clinical relevance of PRP use is debatable.