Magnesium-based materials have potential application value in the field of orthopedics due to their good biodegradability, biocompatibility and bone-promoting properties. However, in the early application process, their main disadvantage was the rapid degradation rate, which limited their clinical application. Nanoparticles can effectively enhance the mechanical strength and corrosion resistance of the magnesium matrix, and different nanoparticles can be selected to achieve different biological functions. Therefore, magnesium-based nanocomposites have become a class of degradable implant materials with broad clinical application potential. This review summarizes the research progress of magnesium-based orthopedic implants, mainly including the enhancement mechanism of nanoparticles on magnesium-based materials, the role and biological functions of different nanoparticle enhancers, surface modification, and the application of new manufacturing technologies. In addition, the degradation process of magnesium-based materials and the biological function of magnesium ions (Mg2+) during the degradation process are discussed in detail. We focus on the biological mechanism by which Mg2+ promotes bone and angiogenesis and inhibits osteoclasts by regulating the immune microenvironment or multiple signaling pathways. Finally, the clinical application of magnesium-based orthopedic implants is introduced, and the future research direction of magnesium-based nanocomposites is discussed.

Innovations:
1. The multiple enhancement mechanisms of nanoparticles on magnesium-based materials were explored in depth, and systematic studies were conducted not only from the perspective of mechanical properties, but also from the perspective of the biological functions of materials.
2. The molecular mechanism of magnesium ions affecting bone tissue regeneration by regulating the immune microenvironment during degradation was innovatively explained, providing new ideas for material design.
3. The introduction of new manufacturing technology into the preparation process of magnesium-based nanocomposites achieved precise regulation of material properties and optimization of functions.
Scientific research inspiration:
1. When studying biomedical materials, more attention should be paid to the interaction between material degradation products and surrounding tissues. This microscopic research may bring important clinical value.
2. The design of materials should develop from a single function to a multi-functional synergistic development, such as considering the optimization of mechanical properties, degradation behavior and biological effects at the same time.
3. The immune microenvironment plays a key role in the process of material-induced tissue regeneration, which provides an important research direction for the development of a new generation of biomaterials.
Extension of ideas:
1. It is possible to explore the use of artificial intelligence technology to predict and optimize the types and contents of nanoparticles and establish a structure-activity relationship model between material properties and biological effects.
2. Study the differences in the degradation behavior of magnesium-based materials under different pathological conditions, and develop intelligent material systems that can adaptively adjust the degradation rate according to the implantation environment.
3. In-depth study of the synergistic effect of magnesium ions and other metal ions, and design new orthopedic implant materials with multi-element synergy.
4. Consider combining magnesium-based materials with stem cell therapy, and use the ions released during the degradation of the materials to regulate the differentiation direction of stem cells and promote tissue regeneration.
5. Explore the possibility of using magnesium-based materials in load-bearing parts, which requires significantly improving the mechanical strength of the material while maintaining good biocompatibility.