On the Two-Dimensional Simplification of Three-Dimensional Cementless Hip Stem Numerical Models

Abstract

Three-dimensional (3D) finite element (FE) models are commonly used to analyze the mechanical behavior of the bone under different conditions (i.e., before and after arthroplasty). They can provide detailed information but they are numerically expensive and this limits their use in cases where large or numerous simulations are required. On the other hand, 2D models show less computational cost, but the precision of results depends on the approach used for the simplification. Two main questions arise: Are the 3D results adequately represented by a 2D section of the model? Which approach should be used to build a 2D model that provides reliable results compared to the 3D model? In this paper, we first evaluate if the stem symmetry plane used for generating the 2D models of bone-implant systems adequately represents the results of the full 3D model for stair climbing activity. Then, we explore three different approaches that have been used in the past for creating 2D models: (1) without side-plate (WOSP), (2) with variable thickness side-plate and constant cortical thickness (SPCT), and (3) with variable thickness side-plate and variable cortical thickness (SPVT). From the different approaches investigated, a 2D model including a side-plate best represents the results obtained with the full 3D model with much less computational cost. The side-plate needs to have variable thickness, while the cortical bone thickness can be kept constant.

A Review of the Selective Laser Melting Lattice Structures and Their Numerical Models

“…[ 47,132,135,143,144 ] Others consider either a frictionless contact [ 20,66 ] or a completely bounded specimen with no slipping allowed. [ 145 ] Lozanovski et al conducted a sensitivity analysis of three tangential frictional coefficients (0.3, 0.6, and 0.9) between the plate and lattice interface and found a negligible difference between the predicted Young modulus and the 0.2% yield stress. [ 132 ] Conversely, Galarreta et al showed that the modulus difference between a model with frictionless contact and a model with 0.2 and 0.3 frictional coefficient is 16.5% and 22.5%, respectively.…”