MECHANICAL STRENGTH OF ACRYLIC BONE CEMENTS IMPREGNATED WITH ANTIBIOTICS

Admixing of several antibiotic powders which were insoluble in methyl methacrylate did not decrease the compressive and diametral tensile strengths of 2 acrylic bone cements when tested after setting for 1 day and after leaching 40 days in H2O at 37.degree. C. When antibiotics were added as water solutions, the included H2O resulted in a significant decrease in these bulk mechanical properties. Storage in water for 40 days caused surface irregularities only on specimens of the set antibiotic admixtures. Approximately 0.5% of the admixed dosage of these H2O-soluble antibiotics could be leached from the set cements. The observed surface channels, presumably left by the loss of antibiotic, suggest further study of surface-sensitive mechanical properties may be needed. The bulk mechanical strengths presented are conclusive only for the particular combinations of antibiotics and cements investigated, and should not be generalized at this time to any or all antibiotic admixtures or other mechanical properties.