Design of an injectable hybrid calcium phosphate-based cement for subchondral bone regeneration

The osteochondral (OC) unit, consisting of articular cartilage and subchondral bone, is essential for joint function. However, its limited regenerative capacity presents challenges. OC defects, arising from excessive loading, trauma, or disease, damage this unit, impacting joint biomechanics and predisposing to degenerative joint disease. Current treatments, while offering temporary relief, cannot fully restore the OC unit. Since there is no current treatment, new strategies aim to develop multilayer biomimetic materials. The goal of this project was to develop a cement for the subchondral bone layer. To this end, hybrid cements based on silanized hyaluronic acid were developed. The addition of polymers resulted in injectable and self-curing cements in an aqueous medium. Moreover, their incorporation improved intermolecular cohesion, resulting in macroporous structures. Polymeric macromolecules improved ductility, allowing greater deformation tolerance. The inclusion of glucose did not have a major impact, probably due to the low concentration. The developed formulations appear promising as injectable bone substitutes for subchondral bone defects. Further analysis will involve biological characterization of biomaterials, which is a combination of in vitro, in vivo, and clinical studies to fully understand how the material interacts with biological systems and how it can be optimized for specific applications.