Non-ionic contrast media in acrylic bone cement

Abstract: Non-ionic, water-soluble, contrast media, iohexol and/or iodixanol, have been investigated for use in acrylic bone cement aimed for arthroplasty. Bone cement, containing the new particulate contrast media , was investigated for: quasi-static mechanical properties, water uptake properties, release of contrast media from the bone cement, biological responses from particulate bone cement, polymerisation reaction, polymerisation temperature, glass transition temperature, injectability and penetration into human cancellous bone, and radiopacity. The quasi-static mechanical properties of acrylic bone cement are influenced by the size and amount of contrast media in the bone cement; the particle size of iodixanol should be above 8 µm in order to have good mechanical properties. At a ratio of 8 wt%, good tensile strength is achieved while creating clear images on a standard X-ray. The molecular weight and glass transition temperature of the cement are not affected by the addition of iodixanol; however, iodixanol does lower the maximum polymerisation temperature. Both iohexol and iodixanol show better biocompatibility than conventional contrast medium; cement particles with iodixanol induce higher bone resorption in vitro than particles with iohexol, and there is a trend that particles with iodixanol show increased bone formation compared to particles with iohexol. The release of iohexol or iodixanol from wet bone cement does not result in a discernable radiolucent zone in the bone cement. The water uptake of cement containing iohexol is significantly higher than that of cement containing iodixanol, which shows higher water uptake than Palacos R. High viscosity cement (Palacos R) achieves better penetration into human cancellous bone in femoral heads than low viscosity cement (Osteopal). Cement containing iodixanol achieves higher bone cement penetration and injectability than low viscosity cement, but lower than Palacos R. The attenuation of X-rays in a contrast medium should be investigated in a standardised way using clinically relevant exposures. Therefore, the attenuation of bone cements (for use in hip- or knee- operations) should be investigated using an X-ray tube voltage of 70 ? 80 kV, with 0.1 m of water as a soft tissue phantom. At 80 kV, with water (similar to clinical situations), iodixanol attenuates photons to the same degree as equal amounts of ZrO2.