Increased cortical porosity in type-2 diabetic postmenopausal women with fragility fractures.
, Burghardt AJ
, Yap SP
, Baum T
, Schwartz AV
, Joseph GB
, Link TM
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA USA. email@example.com.
The primary goal of this study was to assess peripheral bone microarchitecture and strength in diabetic postmenopausal women with fragility fractures (DMFx) and to compare them with diabetic women without fracture (DM). Secondary goals were to assess differences in non-diabetic women with (Fx) and without fragility fractures (Co) and in women with (DM) and without diabetes (Co). Eighty women (mean age 61.3 ± 5.7 yrs) were recruited into these groups (n = 20 per group). Participants underwent DXA and high-resolution peripheral quantitative computed tomography (HR-pQCT) of the ultradistal and distal radius and tibia. In the HR-pQCT images volumetric bone mineral density, cortical and trabecular structure measures, including cortical porosity, were calculated. Bone strength was estimated using micro-finite element analysis (µFEA). Differential strength estimates were obtained with and without open cortical pores. At the ultradistal and distal tibia, DMFx had greater intracortical pore volume (+52.6%, p = 0.009; +95.4%, p = 0.020), relative porosity (+58.1%; p = 0.005; +87.9%, p = 0.011) and endocortical bone surface (+10.9%, p = 0.031; +11.5%, 0.019) than DM. At the distal radius DMFx had 4.7-fold greater relative porosity (p = 0.000) than DM. At the ultradistal radius, intracortical pore volume was significantly higher in DMFx than DM (+67.8%, p = 0.018). DMFx also displayed larger trabecular heterogeneity (ultradistal radius; +36.8%, p = 0.035), and lower total and cortical BMD (ultradistal tibia: -12.6%, p = 0.031; -6.8%, p = 0.011) than DM. DMFx exhibited significantly higher pore-related deficits in stiffness, failure load and cortical load fraction at the ultradistal and distal tibia, and the distal radius than DM. Comparing non-diabetic Fx and Co, we only found a non-significant trend with increase in pore volume (+38.9%, p = 0.060) at the ultradistal radius. The results of our study suggest that severe deficits in cortical bone quality are responsible for fragility fractures in postmenopausal diabetic women. © 2012 American Society for Bone and Mineral Research.
PMID: 22991256 [PubMed - as supplied by publisher]