Advancements in design, surface modification, and spinal applications of biomedical metallic materials for bone repair

Bone defect repair imposes stringent requirements on biomaterials, including mechanical compatibility, biocompatibility, osteoinduction/osteoconduction, and biodegradability. Biomedical metallic materials serve as core solutions for bone reconstruction due to their exceptional mechanical strength, particularly in high-load-bearing regions such as the spine. To address metallic surface bioinertness, various surface modification technologies are widely employed to significantly enhance osseointegration, antibacterial efficacy, and corrosion resistance through micro/nano-structuring and bioactive coatings. 3D printing enables customized fabrication of porous metallic implants, optimizing mechanical compatibility and imaging compatibility. In spinal applications, metallic materials are extensively utilized in internal fixation systems, interbody cages, artificial discs/vertebrae, correction systems, and tumor prostheses. Their design and modification directly impact fusion success rates, anti-subsidence capability, and long-term stability. Despite significant progress, challenges remain in degradation rate matching, long-term biosafety, multifunctional synergy, and stability in complex physiological environments. Future efforts should focus on smart materials, precision surface engineering, AI-assisted personalized design, and long-term clinical evaluation to advance metallic bone-repair materials toward superior performance. • Surface engineering overcomes metal bioinertness: micro/nano-structuring and bioactive coatings boost osseointegration and antibacterial properties. • 3D printing enables customized porous implants: Optimizes mechanical compatibility, imaging, and bone ingrowth for spinal applications. • Metals excel in diverse spinal applications: Key in fixation, fusion cages, discs/vertebrae, correction systems, and tumor prostheses. • Emerging biodegradable Mg/Zn alloys: Offer osteoinduction via ion release, eliminating secondary removal surgery needs. • Future focus on smart materials and AI design: Targets responsive coatings, precision engineering, and personalized implants for performance.