Intra‐Articular Injectable Hydrogel Microsphere‐Based Drug Delivery System for Osteoarthritis Treatment

The prevalence of osteoarthritis (OA), a chronic degenerative joint disease characterized by heterogeneity, is increasing annually owing to factors such as population aging and obesity, which present growing health and economic burdens. Traditional therapies can only slow the progression of OA. The substantial adverse effects of the classical route of administration and complications associated with surgery have highlighted the urgent need for novel therapeutic approaches. As an innovative breakthrough in the field of OA treatment, hydrogel microsphere technology can be used to build a biomimetic microenvironment for cartilage regeneration and establish intelligent drug release owing to its precisely regulated physicochemical properties and excellent biocompatibility. This review first examines the changes in the joint microenvironment and injection barriers caused by OA. The requisite properties of hydrogel microspheres for OA treatment are summarized, and their preparation methods, structural characteristics, and modification strategies are explored. Furthermore, we discuss their application as delivery systems and address the current challenges and future perspectives to enhance their therapeutic efficacy.