Bone microarchitecture of the calcaneus and its changes in aging: A histomorphometric analysis of 60 human specimens

Abstract

Bone structure and quality are an important parameter in the propensity of bone to fracture. Although the calcaneus is used as diagnostic reference site for osteoporosis by ultrasound, its structure has never been analyzed in detail. The purpose of this study was therefore to histomorphometrically analyze the trabecular microarchitecture of the calcaneus, and to determine whether the calcaneal bone structure is changing with age. Sixty complete human calcanei were harvested from thirty age-and gender-matched patients at autopsy. Each of the three different age groups (group I: 20 to 40, group II: 41 to 60, group III: 61 to 80 years of age) was represented by 20 specimens. The specimens were subjected to radiographic, mCT, and histologic analysis. Bone structure and bone mass of the calcaneus were quantified for three different regions of interest: the anterior ROI, the superior ROI (the subtalar region under the posterior facet), and the posterior ROI. An iliac crest biopsy was obtained from all patients to exclude any metabolic bone disease. Histomorphometric analysis revealed significant differences in bone volume within the calcaneus with highest values in the superior ROI: age group I: 31.3% (27.8-34.8%); II: 25.5% (22.1-28.9%); III: 18.9% (16.6-21.2%) and lowest bone volumes in the anterior ROI; age group I: 6.2% (4.8-7.6%); II: 3.6% (2.1-5.1%); III: 3.9% (2.9-4.9%). There was a significant age-related decrease in bone volume (BV/TV) in aging. Interestingly, this bone loss was most prominent in the superior ROI, with a 39% decrease in BV/TV between age group I and III ( p < 0.001). Qualitative and structural analysis of trabecular number, thickness, and spacing demonstrated that the bone loss in the thalamic portion of the calcaneus was due to the transition of plate-like trabecular elements into a rod-like structure. In conclusion, our study demonstrated that the calcaneus displayed age-related changes in its microarchitecture that are known to reduce the biomechanical stability of trabecular bone, and that the age-related bone loss was most prominent in the region adjacent to the posterior facet (superior ROI). These results suggest that bone mass and structure are risk factors in respect to the occurrence and severity of calcaneal fractures, and indicate that calcaneal fractures are at least in part osteoporotic fractures. ß

Bone Microarchitecture of the Talus Changes With Aging

“…Our observations suggested an age-related talar bone loss. This is consistent with results of other skeletal sites such as the distal radius, proximal humerus, and the calcaneus [7,8,37]. Interestingly, the extent of structural changes differed among the three ROIs.…”

“…This study failed to find a sex-specific difference, which is in accordance with histomorphometric results of the calcaneus as one partner of load transmission of the talus where also no differences between males and females were observed [37]. In contrast, sex-specific bone structure differences have been primarily found in less mechanically loaded skeletal sites such as the humeral head or the distal radius [7,8].…”

“…Therefore, given that the mean patient age at total ankle replacement implantation is between 50 and 60 years, knowledge of a potential age effect on bone quality of the talus is of paramount importance [23,42]. It is noteworthy that the anatomical partner of the talus for conferring the contact energy of the foot to the ground, the calcaneus, displays age-related changes in its microarchitecture similar to the proximal humerus or the distal radius [7,8,37]. Although there have been a number of histological analyses of talar microarchitecture, the effects of age and sex on talar microarchitecture changes remain poorly characterized [4,18,21,34,39].…”

Analysis of cartilage matrix fixed charge density and three-dimensional morphology via contrast-enhanced microcomputed tomography

“…CT is an x-ray-based imaging modality capable of 3D, quantitative morphological analysis, and current systems provide images at micrometer-level voxel resolutions. CT imaging has traditionally been applied to hard tissues and is the standard for quantifying trabecular bone microstructural changes associated with aging and osteoporosis (11,12). However, CT has not been useful for direct imaging of soft tissues because of the low x-ray absorption of nonmineralized tissues.…”

Monitoring trabecular bone microdamage using a dynamic acousto-elastic testing method

“…(a) a low-porosity region with a mainly plate-like architecture, located in the upper part of the calcaneus; (b) a higher-porosity homogeneous region, located in the posterior part of the calcaneus (as defined in reference [16]). …”