摘要Osteoarthritis is a common aging-related disorder that is confined mostly to the chondral layer of joints(e.g.,the knee)but can spread to bony layers over time.In its early stages,osteoarthritis has minimal symptoms;however,these gradually worsen over time and include joint pain,stiffness,loss of mobility,and inflammation.The exposed subchondral bone of a Grade 4 osteoarthritic knee is highly prone to erosion if left untreated due to persistent rubbing between the bones,which can lead to painful bone spurs.However,treating osteoarthritis is especially challenging due to the poor mitotic potential and low metabolic activity of chondrocytes.Although currently available tissue-engineered products(e.g.,BST-CarGel?,TruFit?,and Atelocollagen?)can achieve structural reconstruction and tissue regeneration,final clinical outcomes can still be im-proved.Major challenges faced during clinical studies of tissue-engineered constructs include chondrocyte hypertrophy and the development of mechanically inferior fibrous tissue,among others.These issues can be addressed by selecting suitable biomaterial combinations,mimicking the three-dimensional(3D)architecture of the tissue matrix,and better controlling in-flammation.Furthermore,it is crucial to generate essential signaling molecules within the articular cartilage ecosystem.This approach must also account for the microarchitecture of the affected joint and support the chondrogenic differentiation of mesenchymal stem cells.The use of tissue-engineered constructs has the potential to overcome each of these challenges,since materials can be modified for drug/biomolecule delivery while simultaneously facilitating the regeneration of robust ar-ticular cartilage.Three-dimensional printing has been successfully used in tissue engineering to achieve bioprinting.By ma-nipulating conventional 3D printing techniques and the types of bioink used,many different types of bioprinting have emerged.Overall,these bioprinting techniques can be used to address various challenges associated with osteoarthritis treatment.