Structural Changes with Aging in Cortical Bone of the Human Tibia

Abstract

Structural modifications are considered to play a significant role in the age-related alterations of bone quality and strength. Senescent compact bone is characterized by an increasing heterogeneity of aspects, including high numbers of lowly mineralized osteons as well as the presence of osteons with hypermineralized lamellae or with a notched haversian canal wall, and of double-zone osteons. These latter three types of osteons are different from the structures involved in the haversian remodeling. In the present study, blocks of midshaft tibia from 7 young men (18-39 years), 14 aged men (50-92 years) and 15 aged women (57-96 years) were embedded in methyl methacrylate in order to perform microradiographic and histomorphometric analysis of undecalcified sections. The intracortical porosity was higher in the aged men than in the young ones, as were the numbers of haversian structures and, to a lesser extent, the diameters of the haversian canals. The aged women showed the same tendency, with cortical porosity still higher than in the men. The osteons with hypermineralized lamellae, those with a notched canal and the double-zone osteons appear to constitute large subgroups of the total haversian population, even in the early adult life. Among them, only the osteons with a notched canal wall increased in frequency with age. The 3 types are much more numerous than the structures involved in the typical haversian remodeling. The correlations between their frequencies as well as their significant topographic association corroborates the hypothesis that the hypermineralized lamellae may crumble down because of their excessive brittleness, giving rise to the haversian canals with notched walls. These enlarged canals could be refilled-by bone apposition and result in the double-zone osteons. The 3 types of osteons could constitute different steps of one mechanism of bone desinte-gration and repair occurring very progressively, which might contribute to modify the bone quality and to increase the intracortical porosity.

Three‐dimensional reconstruction of Haversian systems in human cortical bone using synchrotron radiation‐based micro‐CT: morphology and quantification of branching and transverse connections across age

“…; Ericksen, ; Nyssen‐Behets et al. ). Ortner () argued that the internal osteons are short and narrow, and might primarily serve mineral exchange.…”

Structural analysis of cortical porosity applied to HR-pQCT data

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A novel scratching approach for measuring age-related changes in the in situ toughness of bone

“…Bone has a highly hierarchical structure and the bone quality may be affected by factors at different length scales: (1) microstructural changes (Nyssen-Behets et al, 1997), (2) microdamage formation (Burr et al, 1997;Fazzalari et al, 1998;O'Brien et al, 2000;Turner, 2002), (3) integrity of bone constituents (Nyman et al, 2005a;Turner, 2002;Wang et al, 2000Wang et al, , 2001Wang and Puram, 2004), and (4) interactions between bone constituents (Boskey, 1992;Walsh and Guzelsu, 1994).…”