title: Finite element prediction of surface strain and fracture strength at the distal radius.
abstract: To better understand the mechanisms underlying distal radius fracture we have developed finite element models to predict radius bone strain and fracture strength under loading conditions simulating a fall. This study compares experimental surface strains and fracture loads of the distal radius with specimen-specific finite element models to validate our model-generating algorithm. Five cadaveric forearms were instrumented with strain gage rosettes, loaded non-destructively to 300 N, and subsequently loaded until failure. Finite element models were created from computed tomography data; three separate density-elasticity relationships were examined. Fracture strength was predicted for three specimens that failed at the distal radius using six different failure theories. The density-elasticity relationship providing the strongest agreement between measured and predicted strains had a correlation of r=0.90 and a root mean squared error 13% of the highest measured strain. Mean absolute percent error (11.6%) between measured and predicted fracture loads was minimized with Coulomb-Mohr failure theory and a tensile-compressive strength ratio of 0.5. These results suggest that our modeling method is a suitable candidate for the in vivo assessment of distal radius bone strain and fracture strength under fall type loading configurations.
authors.affiliation: Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL 60612, USA. edwardsb@uic.edu
authors.forename: W Brent
authors.initials: WB
authors.lastname: Edwards
authors.forename: Karen L
authors.initials: KL
authors.lastname: Troy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D002102:Cadaver; D004548:Elasticity; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D008954:Models, Biological; D011885:Radius Fractures / Q000473:pathology / Q000503:physiopathology*; D013314:Stress, Mechanical; D013718:Tensile Strength; D016474:Weight-Bearing / Q000502:physiology