3D printed scaffolds for reconstruction of segmental long bone defects: A mini narrative review

Large segmental bone defects remain a major challenge in orthopedic reconstruction because successful healing requires both mechanical stability and coordinated biological regeneration. Although autologous bone grafting remains the clinical gold standard due to its osteogenic, osteoinductive, and osteoconductive properties, its application is limited by donor site morbidity, restricted graft availability, and increased operative burden. These limitations have stimulated the development of scaffold-based regenerative strategies aimed at restoring structural integrity while promoting bone regeneration. Recent advances in additive manufacturing have enabled the fabrication of patient-specific three-dimensional (3D) scaffolds with controlled architecture, porosity, and mechanical properties that approximate native bone structure. This mini-review summarizes recent developments in 3D-printed scaffolds for the reconstruction of long bone defects, with particular emphasis on differences between non-biodegradable metallic constructs and biodegradable polymeric, ceramic, and composite materials. Porous titanium scaffolds demonstrate high mechanical stability and early osteointegration, making them promising for extensive load-bearing defects, although concerns remain regarding long-term stress shielding and permanent implant retention. Biodegradable ceramics and polymer-based scaffolds offer improved biological integration and controlled degradation, but often require further optimization of mechanical stability and biological augmentation. Composite constructs combining polymers, ceramics, or bioactive metals aim to integrate structural support with enhanced osteogenic and angiogenic responses. Despite encouraging preclinical results and emerging early clinical applications, current evidence remains limited by small patient cohorts, heterogeneous scaffold designs, and insufficient long-term outcome data. Future studies should focus on standardized scaffold designs, comparative clinical trials, and long-term evaluation to clarify the optimal role of 3D-printed biomaterials in the treatment of large segmental bone defects.