Research advances in bioactive bone graft materials and bone marrow enrichment techniques for bone defect treatment

Bone defects arise from trauma, infection, tumor resection, or congenital deformities, with large defects often progressing to nonunion. Autologous bone grafting is considered the gold standard therapy due to its osteoconductive, osteoinductive, and osteogenic properties, but it is limited by insufficient graft volume and donor-site complications. Allogeneic grafts and early synthetic bone substitutes partially addressed these limitations but typically provided only osteoconductive function and performed poorly in complex microenvironments. Bone tissue engineering utilizes bioactive scaffolds, cells, and factors to promote bone repair through mechanical support, osteogenic regulation, and cellular adhesion/proliferation/differentiation mechanisms. This review synthesizes current evidence on bioactive scaffold materials and bone marrow enrichment strategies for bone defect repair within a scaffold-bone marrow coupling framework. It also highlights key roles of pore architecture, angiogenesis, osteoimmunomodulation, and defect-specific material selection, while critically discussing current limitations, evidence gaps, and future translational directions.