Morphological properties of bone cement mixed with antibiotics

The aim of this study was to examine the morphology of poly(methyl methacrylate) bone cement manually loaded with meropenem and vancomycin, in order to determine the structural changes in the polymer matrix that occur with antibiotic addition, as well as the relationship between antibiotic particles and the matrix and the changes that occur with cement aging. Samples of SmartSet Endurance™ MV bone cement manually mixed with meropenem, vancomycin and their combinations were examined with scanning electron microscopy after 24 hours storage at room temperature in air and after 28 days of incubation in Ringer's solution at 37°C. Manually prepared bone cement was characterized with microporosity of up to 65 μm and homogenous polymer structure that does not change significantly with incubation of 28 days. Incubation causes changes in mechanical properties that result with more pronounced cracking of the parts subjected to bending stress. Adding vancomycin causes increase in cement porosity and irregularity in shape and size of pores, not only by creation of antibiotic-filled voids, but also by interference with polymer formation and creation of microporosity areas. Incubation of 28 days causes release of antibiotic particles almost completely from the surface of the sample and less towards the center, with more meropenem particles being released compared to vancomycin.