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 × 15 × 15-mm cubes of trabecular bone were cut. QCT density (rQCT), compressive elastic modulus (E), compressive yield and ultimate strengths (Sy and Su), and ash density (ρash) of each cube were determined. Regression analysis was performed between ρash and E, Sy, Su and ρQCT, and analysis of covariance was used to identify differences between groups. Power relationships that did not depend on group (p≥0:1) were found between E and ρash (0:74≤r≤0:84; p<0.001) and between strength (Sy and Su) and ρash (r≥0:94; p<0.001). ρash was strongly related to ρQCT (r≥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 ρash that can be used to estimate mechanical properties of trabecular bone with and without metastases.
Keywords: Tumor; Metastases; Trabecular bone; Mechanical properties; Computed tomography