Tensile properties of a bone cement containing non-ionic contrast media

The addition of contrast media such as BaSO4 or ZrO2 to bone cement has adv erse effects in joint replacements, including third body wear and particle- induced bone resorption. Ground PMMA containing particles of the non-ionic water-soluble iodine-based X-ray contrast media, iohexol (IHX) and iodixano l (IDX), has, in bone tissue culture, shown less bone resorption than comme rcial cements. These water-soluble non-ceramic contrast media may change th e mechanical properties of acrylic bone cement. The static mechanical prope rties of bone cement containing either IHX or IDX have been investigated. T here was no significant difference in ultimate stress between Palacos R (R) (with 15.0 wt % of ZrO2) and plain cement with 8.0 wt % of IHX or IDX with mass median diameter (MMD) of 15.0 or 16.0 mum, while strain to failure wa s higher for the latter (p< 0.02). The larger particles (15.0 or 16.0 <mu>m ) gave significantly higher (p< 0.001) ultimate tensile strengths and strai ns to failure than smaller sizes (2.4 or 3.6 <mu>m). Decreasing the amount of IHX from 10.0 wt % to 6.0 wt % gave a higher ultimate tensile strength ( p< 0.001) and strain to failure (p< 0.02). Scanning electron microscopy (SE M) showed the smaller contrast media particles attached to the surface of t he polymer beads, which may prevent areas of the acrylate bead surface from participating in the polymerization. In conclusion, the mechanical propert ies of bone cement were influenced by the size and amount of contrast mediu m particles. By choosing the appropriate amount and size of particles of wa ter-soluble non-ionic contrast media the mechanical properties of the new r adio-opaque bone cement can be optimized, thus reaching and surpassing give n regulatory standards. (C) 2001 Kluwer Academic Publishers.