Bone Quality Parameters of the Distal Radius as Assessed by pQCT in Normal and Fractured Women

Abstract

The aim of this study was to test the ability of some indicators of different aspects of bone quality (assessed by peripheral quantitative computed tomography in the distal radius) to discriminate between fractured and nonfractured individuals. The study compared 214 women aged 45-85 years, free of any bone-affecting treatment, of whom 107 had suffered a Colles' fracture in the previous 6 months and 107 did not. The determinations included bone tissue or mineral 'mass' indicators (trabecular, cortical and total volumetric mineral content, cortical bone area); bone 'density' estimates (trabecular, cortical and total volumetric mineral density), and the Cartesian (rectangular) and polar moments of inertia as influences of cross-sectional architecture on resistance to bending and torsional loads, respectively. The influences of body height, weight and age on the tomographic indicators were minimized by adjusting the data according to the partial coefficients of multiple stepwise regressions. The adjusted values of all the indicators were lower in fractured than in nonfractured groups. The prevalence of fractures was directly related to the actual values of the indicators, rather than the age or body habitus of the individuals. The significance of these differences between the assessed indicators decreased in the following order: trabecular 'mass' > trabecular 'density' > cortical or total 'mass' > cortical architecture > total or cortical 'density' indicators. Within the same type of bone, the tissue or mineral 'mass' indicators performed better than the 'density' indicators. The cortical bone density did not give useful information, probably because of technical difficulties. Odds-ratios and receiver-operating characteristic (ROC) analyses confirmed those features. The selected 'cut-off' values of the indicators as determined by the ROC curves (very close to those determined by the inflexion points of the logistic reression curves) may indicate reference limits to detect persons at risk of fracture according to the type of information provided by each variable. These results show that these tomographic indicators discriminate well between fractured and nonfractured individuals, and should be suitable to assess how total, cortical and trabecular bone strength in the distal radius could affect different kinds of strength regardless of the age or body habitus of the individual. Their ability to estimate fracture risk from different biomechanical points of view should be assessed by adequately designed, prospective studies.

Cortical and trabecular architecture are altered in postmenopausal women with fractures

“…Our results confirm and extend previous ex vivo studies on iliac crest bone biopsies that showed alterations of trabecular and cortical microarchitecture in subjects with fractures [3,5,6,[12][13][14], and previous in vivo studies that reported that trabecular bone microarchitecture is significantly associated with nonvertebral [15,16] and vertebral fractures [17][18][19][20]. The slightly better resolution of the hr-pQCT compared to previous techniques allowed us to extend these prior observations with presumably more accurate assessment of cortical and trabecular microarchitecture.…”

Alterations of Cortical and Trabecular Architecture Are Associated With Fractures in Postmenopausal Women, Partially Independent of Decreased BMD Measured by DXA: The OFELY Study

“…(13,14) In a study comparing 107 women with and 107 women without prevalent wrist fracture and using pQCT at the radius, the trabecular volumetric BMC and BMD data seemed to discriminate fractured and nonfractured cases better than cortical area and vBMC. (40) In another crosssectional study, 21 women with a recent wrist fracture were compared with a control group with no history of fracture and similar volumetric total BMD at the distal radius using pQCT. The average trabecular hole size was larger in women with fracture than in controls, but the connectivity index was not significantly different between both groups.…”

Contribution of In Vivo Structural Measurements and Load/Strength Ratios to the Determination of Forearm Fracture Risk in Postmenopausal Women

“…This is consistent with previous reports of a stronger association of forearm fractures with BMD assessed at predominantly trabecular sites. (35)(36)(37)(38)(39) Although the latter observation has led to the notion that distal forearm fractures stem mostly from trabecular bone loss, cortical bone strength makes an important contribution to forearm fracture risk as indicated by ex vivo studies. (40) In this analysis, cortical bone carried >60% of the load on the radius, and cortical thickness and area were 33% less and 29% less, respectively, in fracture cases compared with controls.…”