Robust QCT/FEA models of proximal femur stiffness and fracture load during a sideways fall on the hip.
Clinical implementation of quantitative computed tomography-based finite element analysis (QCT/FEA) of proximal femur stiffness and strength to assess the likelihood of proximal femur (hip) fractures requires a unified modeling procedure, consistency in predicting bone mechanical properties, and validation with realistic test data that represent typical hip fractures, specifically, a sideways fall on the hip. We, therefore, used two sets (n = 9, each) of cadaveric femora with bone densities varying from normal to osteoporotic to build, refine, and validate a new class of QCT/FEA models for hip fracture under loading conditions that simulate a sideways fall on the hip. Convergence requirements of finite element models of the first set of femora led to the creation of a new meshing strategy and a robust process to model proximal femur geometry and material properties from QCT images. We used a second set of femora to cross-validate the model parameters derived from the first set. Refined models were validated experimentally by fracturing femora using specially designed fixtures, load cells, and high speed video capture. CT image reconstructions of fractured femora were created to classify the fractures. The predicted stiffness (cross-validation R (2) = 0.87), fracture load (cross-validation R (2) = 0.85), and fracture patterns (83% agreement) correlated well with experimental data.
Division of Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. dragomirdaescu.dan@mayo.edu
Dan
D
Dragomir-Daescu
Jorn
J
Op Den Buijs
Sean
S
McEligot
Yifei
Y
Dai
Rachel C
RC
Entwistle
Christina
C
Salas
L Joseph
LJ
Melton
Kevin E
KE
Bennet
Sundeep
S
Khosla
Shreyasee
S
Amin
D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003198:Computer Simulation; D055119:Elastic Modulus; D005260:Female; D005264:Femoral Fractures / Q000209:etiology* / Q000503:physiopathology*; D005269:Femur / Q000293:injuries* / Q000503:physiopathology*; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016474:Weight-Bearing