Vacuum Loading of the Femoral Cement Gun: The Effect on Mantle Porosity

The femoral cement mantle was reproduced in a laboratory model. This model consisted of rigid plastic tubing, 10 cm long, with an internal diameter of 2.5 cm. One end of the tube was sealed to simulate an intramedullary plug. A wooden model was used to simulate the femoral component of a total hip arthroplasty. Bone cement was mixed in a glass bowl with a steel spatula in a standardised manner for two minutes.

In all cases the model femur was filled with bone cement and a regular mantle around the wooden “femoral stem” was observed. Pores were present on the cut surface of all of the specimens. The pore density (No. of pores per unit area) was measured using an NIH image programme and was found to be dramatically reduced in the experimental cement mantles, when compared to the control specimens.

The porosity in the cement mantles produced by vacuum loading the gun was significantly lower (p< 0.001) than that in the mantles produced by the manually loaded guns.