Bone Representation Effects on Carpal Kinematics in Wrist Finite Element Models: A Methodological Comparison.

Wrist biomechanics remain incompletely understood due to the complexity of experimental measurements in this multi-bone joint system. Finite element analysis provides a powerful alternative for investigating internal variables such as carpal kinematics and displacement patterns. This technical brief compares two bone representation approaches, all-cortical versus cortical-trabecular, using two distinct finite element models developed from the same wrist CT dataset. The study evaluates whether simplified all-cortical bone representation can adequately predict carpal displacement during simulated knuckle-based push-ups compared to more complex cortical-trabecular modeling. Model A employs shell-solid elements with comprehensive soft tissue inclusion and an explicit solver, while Model B uses tetrahedral elements with simplified bonded contact and an implicit solver. Results demonstrate that Model A maintains displacement differences within 0.5 mm between bone representation approaches, supporting the viability of simplified modeling when integrated with penalty-based contact and explicit solvers. Model B demonstrates limitations in simplified approaches, with bonded contact creating systematic underprediction of displacements, particularly in the radial column. The findings suggest that modeling approach selection significantly impacts carpal kinematic predictions, with simplified all-cortical representation viable when integrated with appropriate contact algorithms and solver selection. This methodological comparison provides practical guidance for researchers selecting bone modeling strategies in wrist finite element analysis, particularly when balancing model complexity with computational constraints.