Structural patterns of the proximal femur in relation to age and hip fracture risk in women

Abstract

Fractures of the proximal femur are the most devastating outcome of osteoporosis. It is generally understood that age-related changes in hip structure confer increased risk, but there have been few explicit comparisons of such changes in healthy subjects to those with hip fracture. In this study, we used quantitative computed tomography and tensor-based morphometry (TBM) to identify three-dimensional internal structural patterns of the proximal femur associated with age and with incident hip fracture. A population-based cohort of 349 women representing a broad age range (21–97 years) were included in this study, along with a cohort of 222 older women (mean age 79±7 years) with (n=74) and without (n=148) incident hip fracture. Images were spatially normalized to a standardized space, and age- and fracture-specific morphometric features were identified based on statistical maps of shape features described as local changes of bone volume. Morphometric features were visualized as maps of local contractions and expansions, and significance was displayed as Student’s t-test statistical maps. Significant age-related changes included local expansions of regions low in volumetric bone mineral density (vBMD) and local contractions of regions high in vBMD. Some significant fracture-related features resembled an accentuated aging process, including local expansion of the superior aspect of the trabecular bone compartment in the femoral neck, with contraction of the adjoining cortical bone. However, other features were observed only in the comparison of hip fracture subjects with age-matched controls including focal contractions of the cortical bone at the superior aspect of the femoral neck, the lateral cortical bone just inferior to the greater trochanter, and the anterior intertrochanteric region. Results of this study support the idea that the spatial distribution of morphometric features is relevant to age-related changes in bone and independently to fracture risk. In women, the identification by TBM of fracture-specific morphometric alterations of the proximal femur, in conjunction with vBMD and clinical risk factors, may improve hip fracture prediction.

Spatial Differences in the Distribution of Bone Between Femoral Neck and Trochanteric Fractures

“…In this study, we applied statistical multiparametric mapping to investigate spatial differences in proximal femoral density and cortical bone properties between two major types of hip fracture—femoral neck and trochanteric fracture—and healthy controls. In contrast to previous studies, we identified acute hip fracture–related features with both VBM of vBMD and SPM of cortical bone properties, thus providing a more comprehensive QCT assessment of the proximal femur. Investigated features included vBMD, Ct.Th, Ct.vBMD, and EndoTb.vBMD.…”

A two-level subject-specific biomechanical model for improving prediction of hip fracture risk

“…Various clinical studies have demonstrated that hip fracture is affected by anthropometric parameters, bone quality (Haider et al, 2013), proximal femur anatomy (Carballido-Gamio et al, 2013;Gregory and Aspden, 2008;Ito et al, 2010;Park et al, 2014), cortical thickness (Long et al, 2015;Loveridge et al, 2010), hip soft tissue thickness (STT) (Majumder et al, 2007(Majumder et al, , 2008(Majumder et al, , 2013, landing surface (Baddoura et al, 2011;Van der Zijden et al, 2012), etc. All these parameters are subject dependent as they vary with gender, race, ethnicity and age (Peacock et al, 2009;Wang et al, 1994;Zhuang et al, 2010).…”

Focal osteoporosis defects play a key role in hip fracture

“…Ordinary clinical computed tomography (CT) scans have been be used to identify focal 3D bone loss in ageing and as a predictor of fracture [11], [12], [13], [14], [15], [16]. Cortical Bone Mapping (CBM) couples CT imaging capability with an evaluation method to find average differences between groups known as statistical parametric mapping (SPM) [11], [12], [13], [14], [15], [16].…”

“…Cortical Bone Mapping (CBM) couples CT imaging capability with an evaluation method to find average differences between groups known as statistical parametric mapping (SPM) [11], [12], [13], [14], [15], [16]. CBM can also be used to visualise femoral cortical thickness in CT scans from individual patients (Fig.…”