Optimization of the density-elasticity relationship for rabbit hindlimb bones.

Area of Science:

• Biomechanical Engineering
• Orthopaedic Research
• Computational Biology

Background:

• Rabbits are valuable experimental models in orthopaedic biomechanics due to natural Haversian remodeling, offering better human bone mechanobiology relevance than rodents.
• Existing computational modeling approaches, like finite element (FE) analysis, in rabbit studies lack a validated density-elasticity relationship for subject-specific predictions.

Purpose of the Study:

• To determine and validate an accurate density-elasticity relationship for rabbit hindlimb bones.
• To enable precise, subject-specific computational predictions in orthopaedic biomechanics research utilizing rabbit models.

Main Methods:

• Harvested fourteen tibiae and thirteen femora from New Zealand White Rabbits.
• Acquired computed tomography (CT) images and recorded strain gauge data during uniaxial compression.
• Developed subject-specific FE models and employed Nelder-Mead optimization to derive density-elasticity relationships minimizing experimental and FE strain discrepancies.

Main Results:

• Optimized density-elasticity relationships demonstrated strong correlations (R² 0.85-0.96) for tibiae, femora, and combined bones.
• Validation using independent bone subsets confirmed the derived relationships with high accuracy (R² 0.87-0.94).
• The derived relationships showed excellent agreement between experimentally measured and FE-predicted principal strains.

Conclusions:

• The study successfully established validated density-elasticity relationships for rabbit hindlimb bones.
• These relationships are suitable for computational modeling, enhancing the translational relevance of rabbit orthopaedic research.
• A single, unified relationship may suffice for whole-rabbit hindlimb modeling, improving computational efficiency.