A research team at Peking University Third Hospital has developed a '4D metal metamaterial' bone implant. The study leverages the gradual degradation of biodegradable metals (e.g., magnesium-based and zinc-based alloys) to provide dynamic mechanical stimulation over time after implantation, actively promoting bone tissue regeneration and repair through controllable mechanical signaling, replacing the traditional static support design concept for bone implants. The 4D metal metamaterial combines the precision shaping capability of 3D printing for porous structures with the biocompatibility of biodegradable metals, offering a more proactive treatment solution for bone defect repair, particularly in complex scenarios such as large segmental bone defects and osteoporotic fractures.