title: Accuracy of finite element predictions in sideways load configurations for the proximal human femur.
abstract: Subject-specific finite element models have been used to predict stress-state and fracture risk in individual patients. While many studies analysed quasi-axial loading configurations, only few works simulated sideways load configurations, such as those arising in a fall. The majority among these latter directly predicted bone strength, without assessing elastic strain prediction accuracy. The aim of the present work was to evaluate if a subject-specific finite element modelling technique from CT data that accurately predicted strains in quasi-axial loading configurations is suitable to accurately predict strains also when applying low magnitude loads in sideways configurations. To this aim, a combined numerical-experimental study was performed to compare finite element predicted strains with strain-gauge measurements from three cadaver proximal femurs instrumented with sixteen strain rosettes and tested non-destructively under twelve loading configurations, spanning a wide cone (0-30° for both adduction and internal rotation angles) of sideways fall scenarios. The results of the present study evidenced a satisfactory agreement between experimentally measured and predicted strains (R(2) greater than 0.9, RMSE% lower than 10%) and displacements. The achieved strain prediction accuracy is comparable to those obtained in state of the art studies in quasi-axial loading configurations. Still, the presence of the highest strain prediction errors (around 30%) in the lateral neck aspect would deserve attention in future studies targeting bone failure.
authors.affiliation: Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Grassi
authors.forename: E
authors.initials: E
authors.lastname: Schileo
authors.forename: F
authors.initials: F
authors.lastname: Taddei
authors.forename: L
authors.initials: L
authors.lastname: Zani
authors.forename: M
authors.initials: M
authors.lastname: Juszczyk
authors.forename: L
authors.initials: L
authors.lastname: Cristofolini
authors.forename: M
authors.initials: M
authors.lastname: Viceconti
mesh_terms: D005270:Femur Head / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D013312:Stress, Physiological; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing / Q000502:physiology