A preliminary dual-energy X-ray absorptiometry-based finite element model for assessing osteoporotic hip fracture risk

Luo, Yunhua; Ferdous, Zannatul; Leslie, William D.

doi:10.1177/0954411911424975

Cited by 31 publications

(37 citation statements)

References 35 publications

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“…From the mechanical point of view, they mainly include the cortical bone thickness (CBT), aBMD, femoral neck axial length (FNAL), neck-shaft angle ( α ), body weight and height, or body mass index (BMI). We studied how these risk factors affect hip fracture using the subject-specific DXA-based finite element analysis (FEA) (Luo et al, 2011, Luo et al, 2013). The procedure of DXA-based FEA is illustrated in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Finite element analysis (FEA) has been a powerful and popular tool for solving various engineering problems. Finite element analysis of hip fracture based on medical images is a promising tool to improve prediction of fracture risk in individuals (Koivumäki et al, 2012a, Koivumäki et al, 2012b, Naylor et al, 2013, Keyak et al, 2001a, Keyak et al, 2001b, Luo et al, 2011, Luo et al, 2013, Bessho et al, 2007, MacNeil and Boyd, 2008, Lotz et al, 1991, Dickinson et al, 2010, Rhee et al, 2009, Trabelsi et al, 2011, Orwoll et al, 2009, Cody et al, 1999, Cody et al, 2000, Dall'Ara et al, 2013, Lenaerts and Van Lenthe, 2009, Testi et al, 1999, Christen et al, 2010, Langton et al, 2009, Qian et al, 2009, Den Buijs and Dragomir-Daescu, 2011). Hip fracture is resulted by the applied force exceeding its strength.…”

Section: Introductionmentioning

confidence: 99%

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Study of DXA-derived lateral–medial cortical bone thickness in assessing hip fracture risk

2015

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The currently available clinical tools have limited accuracy in predicting hip fracture risk in individuals. We investigated the possibility of using normalized cortical bone thickness (NCBT) estimated from the patient's hip DXA (dual energy X-ray absorptiometry) as an alternative predictor of hip fracture risk. Hip fracture risk index (HFRI) derived from subject-specific DXA-based finite element model was used as a guideline in constructing the mathematical expression of NCBT. We hypothesized that if NCBT has stronger correlations with HFRI than the single risk factors such as areal BMD (aBMD), then NCBT can be a better predictor. The hypothesis was studied using 210 clinical cases, including 60 hip fracture cases, obtained from the Manitoba Bone Mineral Density Database. The results showed that, in general HFRI has much stronger correlations with NCBT than any of the single risk factors; the strongest correlation was observed at the superior side of the narrowest femoral neck with r2 = 0.81 (p < 0.001), which is much higher than the correlation with femoral aBMD, r2 = 0.50 (p < 0.001). The capability of aBMD, NCBT, and HFRI in discriminating the hip fracture cases from the non-fracture ones, expressed as the area under the curve with 95% confidence interval, AUC (95% CI), is respectively 0.627 (0.593–0.657), 0.714 (0.644–0.784) and 0.839 (0.787–0.892). The short-term repeatability of aBMD, NCBT, and HFRI, measured by the coefficient of variation (CV, %), was found to be in the range of (0.64–1.22), (1.93–3.41), (3.10–4.16), respectively. We thus concluded that NCBT is potentially a better predictor of hip fracture risk.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of DXA-derived lateral–medial cortical bone thickness in assessing hip fracture risk

2015

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“…The subject-specific dynamics modeling method developed in this study and the DXA-based proximal femur finite element model proposed in (Luo et al 2011;Luo, Ferdous , & Leslie 2013) can be integrated as a clinical tool for assessing hip fracture risk. The impact force predicted by the dynamics model can be used as the input to the DXA-based femur finite element model in calculating the fracture risk index, which is a ratio representing the applied force to the bone strength (Luo et al 2011;Luo, Ferdous , & Leslie 2013).…”

Section: Internationalmentioning

confidence: 99%

“…Based on theories of material strength and mechanics, whether or not a fall would result in a hip fracture is determined by both the bone strength and the impact force induced in the fall. Finite element analysis (FEA) based on engineering mechanical models (Lotz et al 1991;Testi et al 1999;Keyak et al 2005;Bessho et al 2007;Majumder et al 2007;MacNeil & Boyd 2008;Luo et al 2011;Tsouknidas et al 2012;Luo, Ferdous, & Leslie 2013;Luo, Ferdous, & Ouyang 2013;Naylor et al 2013) has proved to be a promising tool for more accurately assessing hip fracture risk, as it is able to consider all the involved factors based on well-established mechanical theories and mathematical equations. FEA of hip fracture risk usually requires the impact force as an input for assessment.…”

Section: Introductionmentioning

confidence: 99%

Prediction of impact force in sideways fall by image-based subject-specific dynamics model

Luo

Sarvi

Sun

et al. 2014

International Biomechanics

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The impact force applied to the greater trochanter during sideways fall is a critical factor for determining whether or not a hip fracture would occur. However, the impact force is subject-dependent as it is related to the subject's anthropometric parameters and the kinematic variables in fall. It cannot be accurately predicted by the currently available dynamics models. We developed and validated a method for constructing subject-specific dynamics models to more accurately predict the impact force. The anthropometric parameters required in the model were obtained from the subject's whole body DXA (dual energy X-ray absorptiometry) image. The subject-specific dynamics models were then validated by protected fall tests using young volunteers. The effects of anthropometric parameters on the impact force were investigated using 90 clinical DXA images obtained from a local osteoporosis clinic center. The impact forces predicted by subject-specific dynamics models had much better agreement with the experimental data, compared with those predicted by the existing empirical functions. The parametric study results indicated that although body weight and height are the dominant parameters affecting the impact force, other parameters such as the hip vertical velocity before impact also have considerable effects. This finding suggests that the existing empirical functions that only consider body weight and height may not be able to accurately predict the impact force. As whole body DXA images are readily available in osteoporosis clinic centers, the proposed method may have potential applications in the clinic to improve the assessment of fallinduced hip fracture risk.

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“…Alternatively, the fracture risk can be measured by the fracture risk index (FRI), defined as the ratio between the actual stress to the ultimate stress [68][69][70][71]:…”

Section: Biomechanical Variables Determining Hip Fracture Riskmentioning

confidence: 99%

A biomechanical sorting of clinical risk factors affecting osteoporotic hip fracture

Luo

2015

Osteoporos Int

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Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.

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A preliminary dual-energy X-ray absorptiometry-based finite element model for assessing osteoporotic hip fracture risk

Cited by 31 publications

References 35 publications

Study of DXA-derived lateral–medial cortical bone thickness in assessing hip fracture risk

Study of DXA-derived lateral–medial cortical bone thickness in assessing hip fracture risk

Prediction of impact force in sideways fall by image-based subject-specific dynamics model

A biomechanical sorting of clinical risk factors affecting osteoporotic hip fracture

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