Heterogeneity of fracture syndromes in postmenopausal women

Studies were performed on 32 women with vertebral crush fractures (mean age, 65.1 yr) and 27 patients with recent hip fractures (mean age, 83.6 yr). Histomorphometric analysis of undecalcified transiliac crest biopsies revealed significant differences between the two fracture groups. Trabecular bone volume (TBV) was significantly lower in vertebral fracture than in hip fracture patients (12.0 +/- 4.4% (+/- SD) vs. 14.8 +/- 3.6%; P = 0.014), while thickness of cortices was significantly lower for hip fracture than for vertebral fracture patients (436 +/- 231 vs. 823 +/- 465 microns; P less than 0.001). The TBV and radial bone mass (measured by absorptiometry on the shaft) for the vertebral fracture group were significantly lower than age-expected values. For the patients with hip fractures, the TBV was significantly above the expected value, and radial bone mass was not significantly different from the expected value. Other quantitative histological measurements did not generally differ between the two fracture groups and were compatible with normal or increased bone remodeling. The serum PTH in the hip fracture group was significantly increased above that expected in normal women of similar age. These data demonstrate the anatomical heterogeneity of osteoporotic fracture syndromes. Patients with vertebral fractures have an early deficit of trabecular bone for their age, while those with hip fractures have a deficit of both cortical and trabecular bone compared to women of age 50 yr, but the deficit is not excessive compared to others of similar age without fractures.