Monitoring osseointegration and degradation of Mg-alloy implants through plasma biomarkers of inflammation and bone regeneration

Magnesium-degradable implants have excellent mechanical and osteogenic properties for temporary orthopedic use but are underutilized due to insufficient methods to monitor implant osseointegration and tissue healing. This study evaluated the use of circulatory biomarkers to monitor the bilateral implantation of a Mg-alloy in rats’ femurs. A total of 16 biomarkers were measured from plasma samples collected at multiple timepoints up to 90 days post-implantation. Mg-alloy, Ti-alloy, and Sham (noncritical bone defect) groups were followed with computed tomography, histological, and SEM-EDX analysis. The Sham group showed higher DKK1, OPG, VEGF, and KIM-1 levels than implanted groups. The Mg-alloy group had delayed bone regeneration due to gas release but demonstrated active regeneration up to 180 days and superior osseointegration. Elevated IL-10 and reduced FGF23 at day 28 correlated with accelerated implant degradation. These results underline the complex interactions between biomaterials and biological systems in orthopedic applications and show the value of circulating markers to follow-up implantation.