Functional Polyurethane Hydrogels for Cartilage Repair

Articular cartilage (AC) defects can lead to joint destruction and osteoarthritis, necessitating immediate intervention to prevent progressive cartilage degeneration. To support cartilage repair, hydrogels have been explored due to their structural similarity to the extracellular matrix (ECM), offering a hydrated microenvironment for chondrocytes that promotes cell adhesion and proliferation. Polyurethane (PU) is a promising candidate with adjustable mechanical properties, high biocompatibility, and degradability. Given the advantages of both hydrogels and PU for biomedical applications, functional degradable PU hydrogels present a potential solution for cartilage regeneration. This review summarizes the structure-property relationship and degradation mechanisms of PU hydrogels. Their advanced functionalities in cartilage repair are highlighted, including anti-inflammatory and antibacterial properties, controlled drug delivery, injectability, self-healing, and stimulus responsiveness. By reviewing recent advances and emerging technologies, this review provides valuable insights and a future outlook for the development of next-generation cartilage repair materials.