IS THERE ANY DIFFERENCE BETWEEN VACUUM MIXING SYSTEMS IN REDUCING BONE-CEMENT POROSITY

Six vacuum mixing systems, Cemvac(R), Merck(R), Mitvac(R), Optivac(R), Osteobond(R) and Stryker(R), were tested using prechilled Palaces R(R ) bone cement to investigate the reduction of porosity compared to mix ing at atmospheric pressure, In addition the Optivac(R), Osteobond(R), and Stryker(R) were tested using Simplex P(R) bone cement to find out if they were effective in reducing the porosity of a middle viscosity bone cement, All vacuum mixing systems reduced the number of macropor es (>1 mm) and micropores (0.1 mm < voids < 1 mm) and increased the de nsity of both Palaces R(R) and Simplex P. But only the Optivac(R), Str yker(R), and Merck(R) systems reduced the area percentage of macropore s with more than 50% compared to the control, When using Simplex P(R) bone cement, all three mixing systems tested reduced the numbers and t he area percentage of macropores compared to the control. The results show that vacuum mixing is effective in reducing the porosity in both a high viscosity cement such as Palaces R(R) and a middle viscosity ce ment such as Simplex P(R). Not all systems tested were effective in re ducing the number and size of large voids. (C) 1996 John Wiley & Sons, Inc.