Zhu X, Lee CW, Xu H, et al. - A systematic review was performed to uncover the phenotypic alterations of macrophages during osteoarthritis (OA) and summarized the potential therapeutic interventions via modulating macrophages. Researchers conducted a systematic review of multiple databases (PubMed, Web of Science, ScienceDirect, Medline) up to February 29, 2020. Via two independent reviewers, included articles were discussed and evaluated. They examined relevant information with a standardized and well-designed template. The research enrolled a sum of 28 studies. The study revealed the importance of the phenotypic alterations of macrophages in OA development. Due to controversial and conflicting results, the classical phenotypic subcategory of M1 and M2 macrophages was questionable. Thus, future efforts are required to classify macrophages in an exhaustive manner and to use advanced technologies to distinguish the individual roles of each subtype of macrophages in OA.