Mechanical properties, density and quantitative CT scan data of trabecular bone with and without metastases

Pathologic fracture of the hip due to metastatic lesions in bone is a serious problem. This study examined the effect of metastatic lesions on the material properties and quantitative computed tomography (QCT) data of trabecular bone. Twelve distal femora were obtained, four with lytic and/or blastic metastatic lesions (group L), four without lesions but from donors who died from breast, prostate, or lung cancer (group NL), and four from donors with no cancer (group NC). Each specimen was CT scanned, and 56, 15 x 15 x 15-mm cubes of trabecular bone were cut. QCT density (rho(QCT)), compressive elastic modulus (E), compressive yield and ultimate strengths (S-y and S-u), and ash density (rho(ash)) of each cube were determined. Regression analysis was performed between rho(ash) and E, S-y, S-u and rho(QCT), and analysis of covariance was used to identify differences between groups. Power relationships that did not depend on group (pgreater than or equal to0.1) were found between E and rho(ash) (0.74 less than or equal to r less than or equal to 0.84; p < 0.001) and between strength (S-y and S-u) and rho(ash) (r greater than or equal to 0.94; p < 0.001). rho(ash) was strongly related to rho(QCT) (r greater than or equal to 0.99; p < 0.001). These results indicate that metastatic disease does not significantly impair the ability of QCT to provide an accurate and precise estimate Of rho(ash) that can be used to estimate mechanical properties of trabecular bone with and without metastases. (C) 2003 Elsevier Ltd. All rights reserved.