Artificial ligaments in anterior cruciate ligament reconstruction: Coating strategies for PET-based materials

Artificial ligaments, as an important implant for Anterior Cruciate Ligament reconstruction (ACLR), offer notable advantages in early return to sport. However, most artificial ligaments currently used in clinical ACLR are made of polyethylene terephthalate (PET), a polymer characterized by a smooth and hydrophobic surface that limits cell adhesion and tissue growth, leading to the formation of fibrous scar tissue at the tendon-bone interface. To address these limitations, various surface coating strategies have been developed, including biocompatible, tissue inductive, osteoconductive, drug delivery, and immunomodulatory coatings. These approaches improve biological performance, promote ligamentization, and enhance integration with host tissues. Additionally, the application of composite functional coatings and smart responsive coatings offers new directions for future research. Despite promising preclinical results, most studies remain at the animal experiment stage, and the underlying mechanisms need further investigation. This review summarizes recent advances in coating strategies for artificial ligaments, highlighting their functional classification, technical development, and potential for clinical translation. Translational potential statement: To address key challenges in the application of artificial ligaments, such as limited biocompatibility and poor tissue integration, it is essential to understand the current research progress. This review provides a comprehensive overview of the coatings used for ligaments, highlighting the promising role of surface modification in enhancing implant performance. It offers valuable insights for improving the clinical success rate of artificial ligaments and their long term effectiveness in ACLR, thus holding significant clinical translational potential.