This 2024 meta-analysis of 35 clinical trials concludes that corticosteroid (CS) injections for knee osteoarthritis offer benefits comparable to other injectables only in the very short term (≤ 6 weeks). Beyond this window, platelet-rich plasma (PRP) is the most effective and durable option, providing improvements that are both statistically superior and clinically meaningful. While hyaluronic acid (HA) showed a statistical advantage in long-term pain relief over CS, the difference was too small to be perceived as a significant benefit by the patient.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11457815/pdf/EOR-23-0198.pdf