27 RCTs with 3,272 knee osteoarthritis patients were included in this systematic review and meta-analysis comparing intra-articular PRP injections to corticosteroids, normal saline, and hyaluronic acid. Pooled outcomes of interest included changes in WOMAC total scores and VAS pain scores at a six-month follow-up. The analysis revealed that multiple PRP injections were significantly more effective than normal saline and slightly more effective than hyaluronic acid in reducing both VAS and WOMAC scores. Single PRP injections outperformed corticosteroids in lowering VAS scores, and PRP, regardless of dosage, was superior to corticosteroids in reducing WOMAC scores. These findings suggest that PRP injections, especially in multiple doses, may offer a beneficial alternative to current treatments for knee osteoarthritis.