Microdamage assessment of bone-cement interfaces under monotonic and cyclic compression

Area of Science:

• Biomaterials Science
• Orthopedic Biomechanics
• Medical Device Engineering

Background:

• Bone-cement interfaces are critical for joint replacement fixation.
• Previous studies lacked volumetric assessment of microdamage and bone type influence on load transfer.
• Digital image correlation (DIC) and digital volume correlation (DVC) offer advanced analysis capabilities.

Purpose of the Study:

• To quantify the role of different bone types (trabecular, cortical, mixed) in bone-cement construct mechanical behavior.
• To assess microdamage accumulation volumetrically using DVC and finite element (FE) analysis.
• To investigate load transfer mechanisms and mechanical responses under static and cyclic compression.

Main Methods:

• Construction of bone-cement interfaces using varied bone types (trabecular, mixed, cortical).
• In situ mechanical testing under static and cyclic compression.
• Digital Volume Correlation (DVC) for axial displacement and strain field analysis.
• Finite Element (FE) analysis for microdamage assessment (yielded volumes and strains).

Main Results:

• Significantly higher load transfer into the cement region was observed with mainly cortical bone interdigitation.
• Progressive damage accumulation, including microcrack initiation, occurred in the bone-cement interdigitated and cement regions under cyclic loading when using cortical bone.
• High residual strains (εzz_res) were associated with microcrack initiation in the cortical bone group.

Conclusions:

• Bone type significantly influences load transfer and mechanical behavior at the bone-cement interface.
• Cortical bone integration enhances load transfer but increases susceptibility to microdamage accumulation under cyclic loading.
• Volumetric assessment using DVC provides crucial insights into internal damage mechanisms at the bone-cement interface.