title: Effect of finite element model loading condition on fracture risk assessment in men and women: the AGES-Reykjavik study.
abstract: Proximal femoral (hip) strength computed by subject-specific CT scan-based finite element (FE) models has been explored as an improved measure for identifying subjects at risk of hip fracture. However, to our knowledge, no published study has reported the effect of loading condition on the association between incident hip fracture and hip strength. In the present study, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) quantitative CT (QCT) scans of 5500 older male and female subjects were obtained. During 4-7years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as controls from a pool of age- and sex-matched subjects. From the QCT data, FE models employing nonlinear material properties computed FE-strength of the left hip of each subject in loading from a fall onto the posterolateral (FPL), posterior (FP) and lateral (FL) aspects of the greater trochanter (patent pending). For comparison, FE strength in stance loading (FStance) and total femur areal bone mineral density (aBMD) were also computed. For all loading conditions, the reductions in strength associated with fracture in men were more than twice those in women (p≤0.01). For fall loading specifically, posterolateral loading in men and posterior loading in women were most strongly associated with incident hip fracture. After adjusting for aBMD, the association between FP and fracture in women fell short of statistical significance (p=0.08), indicating that FE strength provides little advantage over aBMD for identifying female hip fracture subjects. However, in men, after controlling for aBMD, FPL was 424N (11%) less in subjects with fractures than in controls (p=0.003). Thus, in men, FE models of posterolateral loading include information about incident hip fracture beyond that in aBMD.
authors.affiliation: Department of Radiological Sciences, University of California, Irvine, CA, USA; Department of Biomedical Engineering, University of California, Irvine, CA, USA; Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA, USA. Electronic address: jhkeyak@uci.edu.
authors.forename: J H
authors.initials: JH
authors.lastname: Keyak
authors.forename: S
authors.initials: S
authors.lastname: Sigurdsson
authors.forename: G S
authors.initials: GS
authors.lastname: Karlsdottir
authors.forename: D
authors.initials: D
authors.lastname: Oskarsdottir
authors.forename: A
authors.initials: A
authors.lastname: Sigmarsdottir
authors.forename: J
authors.initials: J
authors.lastname: Kornak
authors.forename: T B
authors.initials: TB
authors.lastname: Harris
authors.forename: G
authors.initials: G
authors.lastname: Sigurdsson
authors.forename: B Y
authors.initials: BY
authors.lastname: Jonsson
authors.forename: K
authors.initials: K
authors.lastname: Siggeirsdottir
authors.forename: G
authors.initials: G
authors.lastname: Eiriksdottir
authors.forename: V
authors.initials: V
authors.lastname: Gudnason
authors.forename: T F
authors.initials: TF
authors.lastname: Lang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D020342:Finite Element Analysis; D050723:Fractures, Bone / Q000000981:diagnostic imaging*; D006620:Hip Fractures / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D010024:Osteoporosis / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011859:Radiography
keywords: Bone strength; F(L); F(P); F(PL); F(Stance); FE; Femur; Finite element analysis; Hip fracture; L; Osteoporosis; P; PL; Quantitative computed tomography; finite element; finite element analysis-computed proximal femoral strength for loading representing a fall onto the lateral aspect of the greater trochanter; finite element analysis-computed proximal femoral strength for loading representing a fall onto the posterior aspect of the greater trochanter; finite element analysis-computed proximal femoral strength for loading representing a fall onto the posterolateral aspect of the greater trochanter; finite element analysis-computed proximal femoral strength for loading similar to that during single-limb stance; lateral; posterior; posterolateral
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