Study Summary

Twenty-four randomized controlled trials including 2751 patients with knee osteoarthritis (KOA) were included in this systematic review and meta-analysis comparing platelet-rich plasma (PRP) injections with hyaluronic acid (HA), corticosteroids, placebo saline solution, bone marrow aspirate concentrate, prolotherapy, and contrast injections. Pooled outcomes of interest included overall complication rates, post-injection pain, joint effusion, synovitis, other medical adverse events, and complication severity. Overall, complications occurred significantly more frequently after PRP injections than comparator injections. PRP demonstrated similar odds of complications compared with HA and corticosteroid injections but significantly greater odds compared with placebo saline injections. Most complications were mild to moderate and self-limiting, with only one report of severe pain. The findings suggest that PRP injections for knee osteoarthritis are associated with a meaningful increase in adverse events relative to placebo, although their safety profile appears comparable to other commonly used injectable therapies.