Platelet-Rich Plasma for Knee Osteoarthritis: A Comprehensive Narrative Review of the Mechanisms, Preparation Protocols, and Clinical Evidence

This narrative review evaluates the use of platelet-rich plasma (PRP) for knee osteoarthritis (KOA) by synthesizing evidence from 40 high-quality studies. PRP, especially leukocyte-poor PRP, shows superior pain relief and functional improvement compared to hyaluronic acid and corticosteroids in patients with mild to moderate KOA. However, inconsistencies in PRP formulations and protocols limit comparability across studies, and long-term benefits over saline are inconsistent. The overall certainty of evidence is moderate, with PRP being safe but costly and variably reimbursed. Standardization of preparation protocols and outcome reporting is essential to enhance comparability and guide clinical practice. Despite its potential benefits, PRP is not yet considered a disease-modifying treatment due to inconsistent evidence, and further research is needed to optimize treatment protocols and confirm long-term efficacy.