Detailed subject-specific FE rib modeling for fracture prediction

Area of Science:

• Biomechanics
• Computational modeling
• Trauma research

Background:

• Current human body models (HBMs) inadequately predict rib fractures and their locations.
• Subject-specific rib models show inconsistent results for fracture prediction.
• Accurate rib fracture prediction is crucial for improving HBMs in impact simulations.

Purpose of the Study:

• To evaluate subject-specific finite element (FE) rib models for predicting rib stiffness and fracture location.
• To assess the impact of clinical CT data and subject-specific material properties on FE model accuracy.
• To compare FE model predictions with physical rib bending tests.

Main Methods:

• Generated subject-specific FE models of the sixth rib from high-resolution CT data.
• Estimated cortical bone surfaces using a calibrated cortical bone mapping algorithm.
• Assigned subject-specific material data to cortical bone and used two trabecular bone modeling strategies.
• Validated FE models against physical dynamic anterior-posterior rib bending tests, comparing force-displacement, strain, and rotation using CORA analysis.

Main Results:

• Seven out of twelve FE rib models successfully predicted fracture locations with a force-displacement CORA score above 0.65.
• The remaining five models showed poor correlation in force-displacement or fracture prediction.
• Ribs with lower Young's modulus, yield stress, and elongation at fracture were associated with prediction failures.

Conclusions:

• Subject-specific FE rib models can predict fracture location in anterior-posterior bending using high-resolution CT data.
• Model accuracy is contingent on sufficient cortical bone thickness and limited porosity.
• Findings offer guidelines for enhancing HBMs for improved rib fracture prediction.