Microarchitecture of the radial head and its changes in aging.

Fractures of the radial head are common; however, it remains to be determined whether the radial head has to be considered as a typical location for fractures associated with osteoporosis. To investigate whether the human radial head shows structural changes during aging, we analyzed 30 left and 30 right human radial heads taken from 30 individuals. The specimens taken from the left side were analyzed by peripheral quantitative computed tomography (pQCT) and micro-CT. The specimens taken from the right elbow joint were analyzed by radiography and histomorphometry. In these specimens pQCT revealed a significant decrease of total and cortical bone mineral density (BMD(to) BMD(co)) with aging, regardless of sex. Histomorphometry revealed a significant reduction of cortical thickness (Ct.Th), bone volume per tissue volume (BV/TV), and trabecular thickness (Tb.Th) in male and female specimens. In this context, mean BV/TV and mean trabecular number (Tb.N) values were significantly lower and, accordingly, mean trabecular separation (Tb.Sp) was significantly higher in female samples. The presented study demonstrates that the radial head is a skeletal site where different age- and sex-related changes of the bone structure become manifest. These microarchitectural changes might contribute to the pathogenesis of radial head fractures, especially in aged female patients where trabecular parameters (BMD(tr) and Tb.Sp) change significantly for the worse compared to male patients.