A multi-scale modelling framework combining musculoskeletal rigid-body simulations with adaptive finite element analyses, to evaluate the impact of femoral geometry on hip joint contact forces and femoral bone growth.

Hans Kainz,Bryce Adrian Killen,Ilse Jonkers,Sandra Shefelbine,Mariska Wesseling,Lorenzo Pitto,Fernando Perez-Boerema,Jose Manuel Garcia Aznar,Xudong Zhang

doi:10.1371/journal.pone.0235966

Hans Kainz, Bryce Adrian Killen + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0235966

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Abstract

Multi-scale simulations, combining muscle and joint contact force (JCF) from musculoskeletal simulations with adaptive mechanobiological finite element analysis, allow to estimate musculoskeletal loading and predict femoral growth in children. Generic linearly scaled musculoskeletal models are commonly used. This approach, however, neglects subject- and age-specific musculoskeletal geometry, e.g. femoral neck-shaft angle (NSA) and anteversion angle (AVA). This study aimed to evaluate the impact of proximal femoral geometry, i.e. altered NSA and AVA, on hip JCF and femoral growth simulations. Musculoskeletal models with NSA ranging from 120° to 150° and AVA ranging from 20° to 50° were created and used to calculate muscle and hip JCF based on the gait analysis data of a typically developing child. A finite element model of a paediatric femur was created from magnetic resonance images. The finite element model was morphed to the geometries of the different musculoskeletal models and used for mechanobiological finite element analysis to predict femoral growth trends. Our findings showed that hip JCF increase with increasing NSA and AVA. Furthermore, the orientation of the hip JCF followed the orientation of the femoral neck axis. Consequently, the osteogenic index, which is a function of cartilage stresses and defines the growth rate, barely changed with altered NSA and AVA. Nevertheless, growth predictions were sensitive to the femoral geometry due to changes in the predicted growth directions. Altered NSA had a bigger impact on the growth results than altered AVA. Growth simulations based on mechanobiological principles were in agreement with reported changes in paediatric populations.

Highlights

Musculoskeletal simulations have been used to examine musculoskeletal loading in paediatric and pathological populations [1,2,3]
Increasing the neck-shaft angle (NSA) primarily increased the first peak of the hip joint contact force (JCF), whereas increasing the anteversion angle (AVA) increased both peaks of the hip JCF and had a larger impact on average hip JCF
Our findings indicated that hip JCF increase with increasing NSA and AVA when the kinematics are maintained

Summary

Introduction

Musculoskeletal simulations have been used to examine musculoskeletal loading in paediatric and pathological populations [1,2,3]. Generic musculoskeletal models developed from cadaveric data of an adult are scaled to the anthropometry of the child [4,5,6]. This procedure neglects subject-specific musculoskeletal geometry, e.g., subject and age-specific femoral neckshaft angle and anteversion angle [7]. To overcome these limitations, patient-specific musculoskeletal models can be generated from medical images of the participants [8,9,10,11]. These studies reported differences in muscle moment arms [12,13], hip joint contact force orientation [14] and joint kinematics [11] between both modelling approaches

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