Predictive value of bone mineral density and morphology determined by peripheral quantitative computed tomography for cancellous bone strength of theproximal femur

Peripheral quantitative computed tomography (pQCT) is an established diagno stic method for assessment of bone mineral density in the diagnosis of oste oporosis, However, the capacity of structural parameters of cancellous bone measured by high-resolution computed tomography remains to be explored. In 33 patients, bone mineral density (BMD) of the proximal femur was measured in vitro by pQCT using cylindrical biopsies from the intertrochanteric reg ion harvested before the implantation of an artificial hip joint, By digita l image analysis of CT scans, parameters derived from histomorphometry desc ribing the microarchitecture of cancellous bone were measured, The biopsies were also loaded to failure by an uniaxial compression test to determine t he biomechanical parameters, Young's modulus, strength, and maximum energy absorption (E-max), Strong correlations were found for BMD vs. mechanical p arameters (r = 0.73 for Young's modulus, r = 0.82 for strength, and r = 0.7 9 for E-max p < 0.001, n = 29), The morphological parameters, bone volume p er trabecular volume (BV/TV), apparent trabecular thickness (app,Tb,Th), ap parent trabecular separation (app,Tb,Sp), and trabecular number (Tb.N), cor related significantly with all mechanical parameters. The combination of mo rphological parameters with BMD in a multivariate regression model led to a n overall, but only moderate, increase in R-2 in all cases. Our data confir m the high predictive value of BMD for the mechanical competence of cancell ous bone of the intertrochanteric region. However, quantification of cancel lous bone structure by image analysis of CT scans may provide additional qu alitative information for the analysis of bone strength. (C) 2001 by Elsevi er Science Inc, All rights reserved.