RESUMO
Introduction: Knee osteoarthritis (KOA) is a progressive joint disease commonly treated with intra-articular injections, including platelet-rich plasma (PRP), hyaluronic acid (HA), or corticosteroids (CS). This updated meta-analysis aims to enhance the statistical power of the results and provide comprehensive clinical evidence that reflects the most current research. By doing so, the authors aim to suggest a reliable estimate for the development of guidelines, addressing the pressing need for effective and minimally invasive treatment options. Methods: PubMed, Scopus, clinicaltrials.gov, Cochrane Central were searched until March 2023, for randomized controlled trials (RCTs) comparing the effectiveness of intra-articular injectable therapies, including PRP, HA, CS, and placebo, in KOA. Data extraction involved baseline characteristics and outcome measures [Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, Visual Analog Scale (VAS) pain scores, KOOS, and IKDC scores] at 1, 3, 6 and 12 months. Statistical analysis, including subgroup analysis, assessment of heterogeneity, and publication bias, was conducted using Review Manager. Results: Our meta-analysis of 42 studies involving 3696 patients demonstrated that PRP treatment resulted in significant pain relief compared to HA injections, as evidenced by improved WOMAC pain (MD: -0.74; 95% CI: -1.02 to -0.46; P≤0.00001; I 2=94%) and VAS pain (MD: -0.65; 95% CI: -1.24 to -0.06; P=0.03; I2=97%) outcomes. Similarly, PRP showed greater efficacy in reducing WOMAC pain (MD: -8.06; 95% CI: -13.62 to -2.51: P=0.004; I 2=96%) and VAS pain (MD: -1.11; 95% CI: -1.64 to -0.59; P≤0.0001; I 2=68%) compared to CS injections, with the most significant improvement observed at 6 months. Conclusions: PRP is an effective treatment for KOA. It provides symptomatic relief, has the potential to reduce disease progression, and has sustained effects up to 12 months. PRP offers superior pain relief and functional enhancement compared to CS and HA injections.