Probabilistic biomechanical finite element simulations: whole-model classical hypothesis testing based on upcrossing geometry

Todd Pataky, Michihiko Koskei, Philip Graham Cox

Research output: Contribution to journalArticlepeer-review


Statistical analyses of biomechanical finite element (FE) simulations are frequently conducted on scalar metrics extracted from anatomically homologous regions, like maximum von Mises stresses from demarcated bone areas. The advantages of this approach are numerical tabulability and statistical simplicity, but disadvantages include region demarcation subjectivity, spatial resolution reduction, and results interpretation complexity when attempting to mentally map tabulated results to original anatomy. This study proposes a method which abandons the two aforementioned advantages to overcome these three limitations. The method is inspired by parametric random field theory (RFT), but instead uses a non-parametric analogue to RFT which permits flexible model-wide statistical analyses through non-parametrically constructed probability densities regarding volumetric upcrossing geometry. We illustrate method fundamen- tals using basic 1D and 2D models, then use a public model of hip cartilage compression to highlight how the concepts can extend to practical biomechanical modeling. The ultimate whole-volume results are easy to interpret, and for constant model geometry the method is simple to implement. Moreover, our analyses demonstrate that the method can yield biomechanical insights which are difficult to infer from single simulations or tabulated multi-simulation results. Generalizability to non-constant geometry including subject-specific anatomy is discussed.

Original languageEnglish
Article numbere96
Issue number11
Publication statusPublished - 7 Nov 2016

Bibliographical note

© 2016, Pataky et al.


  • Biomechanics
  • Computational statistics
  • Finite element analysis
  • Probabilistic simulation
  • Random field theory

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