In vivo degradation and bone reaction of long-term fixation with a magnesium alloy made by twin-roll casting in a rat femur model.

Background: The effect of casting parameters on the microstructure and corrosion resistance of Mg alloys is still limited, especially in clinical animal experiments.

Objective: We prepared a new magnesium rare earth alloy (Mg-Re, where Re is Ce or La) by vertical two-roll casting and Mg-A by further rolling. The microstructure characteristics, degradation behavior, and bone reaction of the two alloys were studied.

Method: Ti, Mg-Re, and Mg-A alloy plates were implanted in a rat femur model, and their degradation behavior was observed 48 weeks later.

Results: In vivo experiments showed no significant changes around the femur in the Ti group, excluding external factors that may cause bone remodeling and lead to new bone formation. Mg-A induces more new bone formation than Mg-Re, which meets the necessary conditions to prevent pathological fracture. The specimen staining and sectioning showed that the liver and heart of rats implanted with magnesium alloys had no pathological changes and the cell structure was normal, similar to that of rats without a magnesium alloy.

Conclusion: Mg-A alloy has good healing potential as a biodegradable implant material.