Is the Stryker Revolution Mixing System Fit for Purpose? Reliability and a Micro-Ct Assessment of Cement Porosity

The Stryker Revolution™is a new mixing system that employs a high vacuum and a motorised mixing spatula in an effort to reduce cement porosity. We have compared Revolution™with Depuy Cemvac®, in terms of system reliability and cement porosity. Standardised Simplex P® and SmartSet® HV cement samples were produced using both mixing systems and analysed using a micro-CT scanner. The overall porosity, number and volume of voids were measured. Void analysis was subdivided into macro-pores (>0.5 mm³) and micro-pores (0.0005–0.5 mm³). Both systems were easy to use and no breakages were encountered. There was no significant difference in overall porosity between Revolution™ and Cemvac®. Revolution™ produced over a five-fold decrease in average macro-pore size with medium viscosity cement (p=0.02), but produced a greater number of micro-pores (p<0.01). SmartSet® HV specimens had a higher porosity compared to Simplex P®. This study demonstrated that the Revolution™ system was reliable and reduced porosity at least as effectively as the established Cemvac® system. The Revolution™ produced a greater number of smaller pores and further testing is required to establish if this results in a significant mechanical benefit.