Secondary osteon variants and remodeling in human bone

Abstract

Histomorphometric analysis of human cortical bone has documented the occurrence of secondary osteon variants. These include drifting osteons which form tails as they move erratically through the cortex and Type II osteons which show partial resorption and redeposition within the cement line of the osteon. Little is known about the biological significance of these variants. Prior studies suggested correlations with age, biomechanics, diet, and mineral homeostasis. No study has yet tested for osteon variant associations with static measures of bone remodeling. In this study, thin sections (n = 112) of the posterior femur representing a late English Medieval adult human osteological collection, subdivided by age, sex, and socio-economic status, were examined to determine whether remodeling indicators reconstructed from osteon parameters (area, diameter, area ratios) and densities differed between categories of presence or absence of Type II and drifting osteon variants. Of the 112 sections, 33 presented with Type II osteons, and 38 had drifting osteons. Sporadic statistically significant results were identified. Haversian canal:osteon area ratio differed (p = 0.017) with Type II osteon presence, Type II osteons were more prevalent in males than females (p = 0.048), and drifting osteons were associated with smaller osteon (p = 0.049) and Haversian canal area (p = 0.05).These results may be explained through some biological (sex) and social (status) processes such as a period of physiological recovery (e.g., following lactation, malnutrition). However, the general lack of consistent relationships between osteon variants and remodeling indicators suggests they occur as a result of natural variation.

The lifestyles of Bronze Age Zagros highlanders at Deh Dumen, Iran: Insights from midshaft femur cross‐sectional geometry and histology

“…Where cement lines were not clearly visible, only Haversian canals were examined. Finally, a ratio variable H.Ar/ On.Ar (Cooke et al, 2022;Miszkiewicz & Mahoney, 2019) was calculated to approximate % of canal space, serving as a proxy for bone multicellular units (BMUs) activity that executes remodelling in live bone (van Oers, Ruimerman, Tanck, et al, 2008).…”

Automatic Segmentation of Osteonal Microstructure in Human Cortical Bone Using Deep Learning: A Proof of Concept

“…Drifting osteonal structures were classified as intact or fragmentary based on the aforementioned criteria and following guidelines proposed by Robling and Stout [ 14 ]. Type II and double zonal osteons were identified following descriptions and guidance from previous studies [ 36 , 37 ].…”

Female bone physiology resilience in a past Polynesian Outlier community

“… Haversian canal:osteon area ratio (H.Ar/On.Ar), measured in μm 2 separately, and then converted to unitless (dimensionless variable (DV)) ratio values (e.g. 45 , 56 , 60 ): H.Ar is the average area (total area/total number of measured canals) of intact Haversian canals measured from three intra-cortical ROIs of 2.05 mm 2 area each (totalling 6.15 mm 2 ); On.Ar is the secondary osteon area in μm 2 created from average area (total area/total number of measured secondary osteons) of intact secondary osteons with complete cement lines measured from three intra-cortical ROIs of 2.05 mm 2 area each (totalling 6.15 mm 2 ). Secondary osteons cut off by an image border were excluded.…”

“…We selected the posterior midshaft femur because of its biomechanical versatility reflecting sex-specific lifestyles and sexual dimorphism, which we first evaluated in this sample through basic gross measures of femoral size (midshaft circumference, cortical width, maximum length 54 ) and robusticity indices 55 computed from these values. Next, we created thin sections from which we measured standard static histological variables (vascular canal and osteon area to compute canal-osteon ratios 56 , and localised osteon density 40 ) as proxies for bone remodelling activity, and vascular porosity as a proxy for bone blood supply and reflecting bone tissue organisation 41 . Histology was examined in intra-cortical, and combined (including periosteal and endosteal areas) cortical regions of interests (ROIs) of the thin sections (Fig.…”