SDC4 and osteoarthritis: This review analyzed 97 publications (1987–2025) from Pubmed and the Web of Science Core Collection using specific key words (syndecan-4, shed syndecan-4, and osteoarthritis), providing a comprehensive overview of the current research on sSDC4, including its shedding enzymes and specific cleavage sites, as well as the factors and mechanisms that influence SDC4 shedding.