Measurement of Internal Implantation Strains in Analogue Bone Using DVC

Area of Science:

• Biomedical Engineering
• Orthopaedic Surgery
• Materials Science

Background:

• Cementless orthopaedic implant survivorship depends on initial stability.
• Inadequate press-fit causes micromotion, pain, and revision; excessive press-fit damages bone.
• Understanding strain generation during implantation is crucial for optimizing implant design and surgical technique.

Purpose of the Study:

• To develop and validate a Digital Volume Correlation (DVC) methodology for measuring volumetric strain during orthopaedic implant insertion.
• To compare experimental DVC measurements with Finite Element (FE) modeling predictions.
• To identify limitations and suggest improvements for future strain measurement techniques in this field.

Main Methods:

• A simplified implant model was inserted into analogue bone using a custom loading rig.
• Micro-computed tomography (micro-CT) was used to capture volumetric data.
• Digital Volume Correlation (DVC) was applied to measure full-field strain, with results compared to FE analysis.

Main Results:

• DVC successfully measured strain patterns throughout the analogue bone volume during simulated implantation.
• Correlation coefficients indicated strain localization and potential interface failure.
• FE model strain magnitudes were approximately double the experimental DVC measurements, suggesting a need for refined interface failure models.

Conclusions:

• Digital Volume Correlation (DVC) is a viable method for assessing volumetric strain during orthopaedic implant insertion.
• Discrepancies between DVC and FE models highlight the need for improved interface failure modeling, particularly accounting for bone structure behavior.
• Recommendations are provided for optimizing DVC subvolume size in future studies involving similar materials and geometries.