Age‐ and sex‐related changes of humeral head microarchitecture: Histomorphometric analysis of 60 human specimens

Abstract

Fractures of the humeral head are frequent and will further increase due to demographic changes. Prior to operative fracture treatment, the regional differences of bone quality, especially of elderly people, have to be carefully considered to assure stable implant fixation. However, conclusive data concerning the variation of histomorphometric parameters are still lacking. Consequently, the purpose of this study was to analyze the age-and sex-related changes in bone microarchitecture. For that reason, 60 proximal humeri were harvested from patients at autopsy. Twelve regions of interest (ROI) were defined for each centered coronar humeral head slice and the specimens were subjected to radiographic, histological, and histomorphometric analyses. We could demonstrate that in contrast to men, women over 60 years of age had a significant age-related decrease in bone mass. The most prominent decrease was observed in the region of the greater tuberosity, which represents an osteoporotic fracture site. The most superior and medially located part of the centered coronar humeral head slice showed, independent from age and sex, the highest bone mass and can therefore be considered as the best location for subchondral screw placement. Taken together, our study revealed distinct sex-related changes of the humeral head bone microarchitecture with aging, which should be considered in implant positioning. 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.…”

“…Here, the transfer of vertical loading forces into tensile forces while standing and walking might have prevented major age-related bone deteriorations. Hence, the ROI-specific bone loss might be the result of different mechanical loading conditions [5,7,35]. Because the distribution of compressive and tensile forces through the talus does not severely change with age, we speculate that the differently sized volumes of interest might be responsible for the greater bone loss in the body [34].…”

“…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].…”

Proximal humeral fractures: an understanding of the ideal plate positioning

“…Biomechanical studies have shown postero-inferior and antero-superior humeral head areas as appropriate for screw placement, providing satisfactory bone purchase [34,35]. Screw placement into the subchondral bone can prevent varus collapse and secondary humeral head cutout.…”