Topography-based implants for bone regeneration: Design, biological mechanism, and therapeutics

With the increasing demand for bone defect repair, bone implant materials have emerged as a critical alternative to traditional autologous or allogeneic bone grafts. However, their clinical performance remains limited due to challenges such as prolonged healing times and suboptimal repair quality. Moreover, in patients with certain pathological conditions (e.g., diabetes mellitus and osteoporosis), disruptions in the bone microenvironment further compromise regenerative outcomes. To address these limitations, surface modification strategies have been developed to regulate implant-bone tissue interactions and improve therapeutic efficacy. This review systematically summarizes recent advances in bone regeneration implants with a focus on topographical modifications, encompassing design principles, underlying biological mechanisms, and therapeutic applications. Particular attention is given to the influence of implant surface topography on the biological behaviors of osteoblasts, osteoclasts, and macrophages within the bone microenvironment, as well as their responses under complex pathological and physiological conditions. The review also discusses current challenges related to achieving micro/nanoscale structural balance, personalization, and clinical translation of implant surface topographies, and highlights future directions in precision bone regeneration through multidisciplinary approaches, artificial intelligence-driven optimization, and long-term clinical validation. Collectively, these insights may inform future research on bone implant materials and support the development of novel strategies for personalized treatment of bone defect repair.