Mechanical properties of bone cement. Importance of the mixing technique.

The compressive and shear strength and the modulus of elasticity were studied in three different bone cements (CMW, Simplex P, and Zimmer low-viscosity cement). One hundred four specimens were prepared by either a conventional manual mixing technique or mechanical vibration. Mechanical mixing gave a significant increase in shear strength for CMW and Simplex P. The compressive strength of Simplex P and Zimmer low-viscosity cement was significantly improved by mechanical mixing. The scatter of the results was significantly reduced by mechanical mixing. The modulus of elasticity was significantly increased by mechanical mixing for the three cements. The uniformity of the bone cement mass seems to be increased by a standardized mechanical mixing technique.