Comparative Clinical Effectiveness of Intra-Articular Leukocyte-Rich Platelet-Rich Plasma and Hyaluronic Acid in Treating Knee Osteoarthritis Pain: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Nineteen trials and 1771 patients sounds like a large body of evidence, but the trials disagreed with each other for most outcomes (I² above 90% at several timepoints), so the pooled average hides real differences between studies. The authors note that pooling many small trials can inflate the apparent effect, and several of the included trials had small samples. The PRP was not the same product across trials: centrifugation speed, activation method and the resulting leukocyte and platelet concentration varied with the commercial kit used, and some trials did not report them, so the pooled result does not describe one standardised injection. The literature search closed in July 2023 and the authors acknowledge a later randomised trial that was excluded because of the cut-off date. The article does not state the WOMAC scale range, so the reader cannot judge how large the twelve-month physical function and stiffness differences really are. The GRADE table and the results text disagree: for pain at three months the text reports a significant mean difference (95% CI −0.40 to −0.08) while the table reports a standardised difference whose interval crosses zero.

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Do not read this as showing PRP works for knee osteoarthritis. Pain was the primary outcome, and it separated from hyaluronic acid at only one of four timepoints, three months, by under a quarter of a point on a 0-to-10 scale. The twelve-month physical function and stiffness results rest on four trials each, and the authors themselves describe the stiffness advantage as uncertain.