Platelet-Rich Plasma for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Structural Outcomes
E. Pasqualotto, L. Lunelli, T. Pasqualotto, F.B. De Sousa, L.F.Z. Funchal, F.B. Dos ReisObjectives:
To assess the impact of platelet-rich plasma (PRP) on imaging-based structural outcomes in patients with knee osteoarthritis (OA).
Methods:
PubMed, Embase, and the Cochrane Library were systematically searched for randomized controlled trials (RCTs) published up to November 2025 evaluating imaging-based structural effects of PRP in knee OA. Risk ratio (RR) was used to evaluate binary outcomes and standardized mean differences (SMDs) or mean differences (MDs) for continuous endpoints, with 95% confidence intervals (CIs). Statistical analyses were conducted using R software, version 4.4.1.
Results:
A total of 12 RCTs involving 1,200 patients were included. In the pooled analysis, PRP was associated with greater improvement in patellofemoral cartilage thickness/volume compared with control treatments (SMD 0.94; 95% CI, 0.53 to 1.34), whereas no significant differences were observed for medial tibial cartilage thickness/volume or cartilage defect progression. Magnetic resonance imaging (MRI)-based structural scores showed no between-group differences in Whole-Organ Magnetic Resonance Imaging Score (WORMS) osteophytes or subchondral cysts, although PRP demonstrated a significant reduction in bone marrow edema (SMD –0.40; 95% CI, –0.71 to –0.09). Synovitis did not differ overall between groups (SMD –0.22; 95% CI, –0.43 to 0.00).
Conclusion:
In this systematic review and meta-analysis, PRP demonstrated low effects on structural outcomes of knee OA, and did not confer significant benefits in medial tibial cartilage measurements, cartilage defects, synovitis, or most MRI-based WORMS domains. Thus, the findings did not provide clear evidence supporting PRP as a structural disease-modifying treatment. Additional high-quality RCTs using standardized imaging endpoints are warranted.