Bone cement with an antibiotic additive is currently widely available, gentamicin being the most common type. However, the high resistance of such organisms as staphylococci to gentamicin has popularised the practice of adding additional antibiotic powders to the cement mix.

This study aims to quantify the effects of adding 1g active of seven antibiotics on the viscoelastic properties of the cement from mixing to set time using a robust rheometer, developed at the University of Leeds. CMW1 Radiopaque cement was the base cement selected for its widespread familiarity.

Viscosity and elasticity were recorded at two rates of shear until the cements set. Viscosity was found to decrease with shear rate, but the cements were found to have a significant elastic component that greatly increased with shear rate. This indicates that for maximum cement penetration, maintained pressure would be more effective than “hammering”.

It should be noted that the effects described above are small compared to other theatre variables, especially temperature and humidity.