<p>Bone mineral density (BMD) around the implant may decrease post-total hip arthroplasty (THA), and it is important to evaluate changes in BMD pre- and post-THA. Dual-energy X-ray absorptiometry (DXA) is commonly used to evaluate BMD. However, in patients with hip osteoarthritis (OA), BMD obtained from DXA may be affected by bone deformities. Dual-energy computed tomography (DECT) can be used to produce material density image (MDI) that provide the material density values for arbitrary materials. This study aimed to determine the clinical utility of BMD assessment using DECT in patients with OA. The subjects were 80 patients (136 femurs) who underwent DECT and DXA of the femur between January 2021 and September 2023 and were classified into groups with and without OA. Calcium-water (Ca/W) density images were used for MDI. Correlation coefficients between the material density values obtained from Ca/W density images and DXA-obtained BMD were determined at the femoral neck, greater trochanter, and shaft. The femoral material density values obtained from Ca/W density images positively correlated with the DXA-obtained BMD. The correlation coefficients were 0.803 for the femoral neck, 0.762 for the femoral greater trochanter, and 0.598 for the femoral shaft in the group without OA, and 0.629 for the femoral neck, 0.825 for the femoral greater trochanter, and 0.634 for the femoral shaft in the group with OA. Our current study demonstrates that the density values obtained from the Ca/W density image suggest that it could serve as an indicator of femoral BMD.</p>