Clinical efficacy of platelet rich plasma injections for knee osteoarthritis: a review

Osteoarthritis (OA) of knee is a leading cause of global disability, with a rapidly increasing prevalence. This review synthesizes evidence on the clinical efficacy of platelet rich plasma (PRP) injections for managing knee OA, compared to placebo, hyaluronic acid (HA), corticosteroids (CSC), and other therapies. Recent high-quality meta-analyses and systematic reviews demonstrate that intra-articular PRP injections provide superior and clinically significant improvements in pain visual analog scale (VAS) and functional outcomes (WOMAC scores) at 3, 6, and 12-month follow-ups compared to these alternatives. The therapeutic benefit of PRP is highly dependent on platelet concentration, with high-concentration preparations (>800,000 platelets/μL) proving essential for achieving sustained long-term efficacy. Furthermore, a regimen of 2-3 injections is more effective than a single administration. While combination therapy (PRP+HA) may offer superior short-term relief, PRP monotherapy yields equal or better long-term results. PRP also exhibits an excellent safety profile, comparable to placebo and superior to repeated corticosteroid use. PRP, particularly high-concentration delivered in a series, represents an effective, durable, and safe biological treatment for mild to moderate knee OA, outperforming traditional conservative options. Standardization of protocols and cost-effectiveness analyses are recommended for wider clinical adoption.