Effects of Alendronate Sodium Content on the Interface Strengths of Composite Acrylic Bone Cement

Objective. Aim to study how the content of alendronate affected shear strengths at bone-bone cement-metal interfaces. Methods. All samples were divided into 6 groups, G(0)–G(5). On the 1st and 60th day after surgery, bone-bone cement interface shear strengths and bone densities were examined. Interface strengths of metal-bone cement specimens were studied before immersion and 4 weeks after immersion. Results. On the 60th day, bone-bone cement interface shear strengths and bone densities showed significant differences (P < 0.05), and compared with G(0), G(2)–G(5) values increased significantly (P < 0.05), and the peak value was met in G(3). Compared with the 1st day, on the 60th postoperative day both factors decreased significantly in G(0) and G(1) (P < 0.05). Four weeks after immersion, with the increasing dose of alendronate, the shear strengths decreased gradually and in G(5) decreased significantly (P < 0.05). Compared with before immersion, the metal-bone cement interface strengths decreased significantly 4 weeks after immersion (P < 0.05). Conclusions. 50–500 mg alendronate in 50 g cement powders could prevent the decrease of shear strengths at bone-bone cement interfaces and had no effect on metal-bone cement interface strengths. While the addition dose was 100 mg, bone cement showed the best strengths.