Multiscale morphological analysis of bone microarchitecture around Mg-10Gd implants.

Area of Science:

• Biomaterials Science
• Orthopaedic Engineering
• Bone Tissue Engineering

Background:

• Biodegradable magnesium (Mg)-based implants offer a transformative approach in orthopaedics.
• Magnesium-10 weight percent gadolinium (Mg-10Gd) alloy is developed to improve Mg degradation and mechanical properties for bone healing.
• While Mg-10Gd shows favorable osseointegration, its impact on bone microarchitecture during degradation is unexplored.

Purpose of the Study:

• To investigate the effect of Mg-10Gd degradation on bone microarchitecture.
• To compare the ultrastructural adaptation of bone around Mg-10Gd implants versus titanium (Ti) implants.
• To analyze vascular porosity, lacunar porosity, and lacunar-canaliculi network (LCN) morphology.

Main Methods:

• Hierarchical three-dimensional imaging using synchrotron radiation.
• Image-based finite element modelling.
• In vivo study in a rat model comparing Mg-10Gd and Ti implants from 4 to 20 weeks post-implantation.

Main Results:

• Mg-10Gd degradation was associated with significantly lower lacunar density in surrounding bone compared to Ti implants (p < 0.05).
• No significant differences were observed in LCN morphology or fluid flow analysis between Mg-10Gd and Ti groups.
• A more pronounced reduction in lacunae distribution, rather than morphological changes, was noted around Mg-10Gd implants.

Conclusions:

• Mg-10Gd degradation leads to altered bone microarchitecture, specifically reduced lacunar density.
• The findings suggest potential disparities in bone remodeling rates between Mg-10Gd and Ti implants.
• This research deepens the understanding of Mg-10Gd degradation's implications for osseointegration and orthopaedic applications.