The Distal Radius, the Most Frequent Fracture Localization in Humans: A Histomorphometric Analysis of the Microarchitecture of 60 Human Distal Radii and Its Changes in Aging

Background: The distal radius is the most frequent fracture localization in humans. Although younger patients receive a distal radius fracture after an adequate trauma, elderly patients suffer fractures through low-energy mechanisms. Low-energy fractures are hallmarks of osteoporosis. Osteoporotic changes of the distal radius are well described by DXA and peripheral quantitative computed tomography measurements. However, to date, the effects of aging on the microarchitecture of the distal radius have not been investigated. Methods: To investigate whether the microarchitecture of the human distal radius shows osteoporotic changes in bone mass and structure during aging, we dissected out 60 complete human distal radii from 30 age-and gender-matched patients at autopsy. Each of the three different age groups (group I: 20 40 years, group II: 41 60 years, group III: 61-80 years) was represented by 10 autopsy cases and 20 specimens (double-sided extraction), respectively. The specimens were analyzed by peripheral quantitative computed tomography, contact-radiography, and histomorphometry. Results: We observed a significant age-related decrease in bone mass, bone mineral density and an increase in typical osteoporotic changes of the bone microarchitecture in female distal radius specimens. Comparable observations of age-related changes have not been made in male specimens. Conclusions: The distal radius is a location of osteoporosis-specific bone changes. Our data provide evidence for the occurrence of typical osteoporotic changes, especially postmenopausal osteoporotic changes, in the distal radius during aging.