Analysis of trabecular microarchitecture of human iliac bone using microcomputed tomography in patients with hip arthrosis with or without vertebral fracture.

Iliac bone samples were obtained from 50 women with osteoarthrosis of the hip (50-80 years of age) during hip surgery for total hip joint replacement. After determining the resolution and threshold for the binary image, the two-dimensional (2D) and three-dimensional (3D) data of the trabecular structure were obtained in these iliac bone samples using microcomputed tomography (micro-CT). Conventional histomorphometry was then performed. Both 2D and 3D parameters of the trabecular structure were significantly correlated with the parameters of conventional histomorphometry (r = 0.63-0.86 in 2D analysis, and r = 0.60-0.77 in 3D analysis). The patients were classified into the non-spinal-fracture group (n = 36) and the spinal fracture group (n = 14). There was no significant difference in patient age between the two groups. The parameter values of bone mass, such as 2D fractional trabecular bone area and 3D fractional bone volume, and the values of trabecular number (Tb.N) in terms of both 2D and 3D analyses were significantly smaller, and those of trabecular separation (Tb.Sp) were significantly higher in the spinal fracture group than in the non-spinal-fracture group. Trabecular thickness (Tb.Th) values did not significantly differ between the two groups. There was no significant difference between 2D and 3D parameters in discriminating the spinal fracture group from the non-spinal-fracture group. However, 3D analysis demonstrated that the value of the bone surface to bone volume (BS/BV) ratio could discriminate between these two groups. These data demonstrated that micro-CT can evaluate the 3D structure of the human iliac bone, and that decreases in the parameters of the 3D-structure-related bone surface density as well as decreases in trabecular bone volume are related to osteoporotic fracture.