Amniotic Biologics for Knee Osteoarthritis: Promise, Evidence, and Unmet Needs-A Narrative Review

Background: Knee osteoarthritis (KOA) is a leading cause of chronic pain and functional disability worldwide. Despite the widespread use of intra-articular (IA) corticosteroids and hyaluronic acid (HA), their long-term efficacy remains limited. Amniotic and chorionic membrane-derived biologics have emerged as promising alternatives owing to their anti-inflammatory, anti-fibrotic, and regenerative properties. Methods: This narrative review employed a structured, transparency-oriented literature search approach across PubMed/MEDLINE, EMBASE, Cochrane CENTRAL, and ClinicalTrials.gov (2015-2025). Studies evaluating intra-articular amniotic or chorionic membrane biologics in knee OA and reporting clinical outcomes were included. Results: Nine studies met the inclusion criteria, encompassing randomized controlled trials, prospective cohort studies, and retrospective analyses. Across studies, IA amniotic and chorionic membrane biologics demonstrated clinically meaningful improvements in pain scores and functional outcomes, with a favorable safety profile and minimal adverse events reported. Conclusions: Intra-articular amniotic and chorionic membrane biologics represent a promising therapeutic option for knee OA, with emerging evidence supporting their anti-inflammatory and potentially chondroprotective effects. Standardized product characterization, rigorous randomized controlled trials, and long-term follow-up studies are needed to establish their definitive clinical role.