Device for producing reduced porosity bone cement

A mixing device for producing reduced porosity bone cement, comprising:

• a mixing cylinder (3) having a mixing space, the mixing space having wall surfaces to which clumps of bone cement adhere during mixing of components of the bone cement;
• means (4) for mixing the components in the mixing space,
• a front member (5) provided at a front end of the mixing cylinder, the front member (5) having a discharge opening (13) for discharging bone cement from the mixing space,
• a movable piston (6) fixably mounted at a rear end of the mixing cylinder, the movable piston being releasable from the rear end of the mixing cylinder and movable in the mixing space toward the discharge opening (13) for collecting the clumps of bone cement adjacent the discharge opening, and for discharging bone cement (2) through the discharge opening (13);
• and
• a vacuum source (21) connected to the mixing device, generating a vacuum in the mixing space during mixing of the components;
• wherein, when the movable piston (6) is released from the rear end of the mixing cylinder and moved in the mixing space for collecting the clumps of bone cement adjacent to the discharge opening (13) such that the vacuum generated in the mixing space by the vacuum source generates a vacuum in pores formed in the bone cement (2) during the collecting of the clumps of bone cement, whereby the size of the pores is reduced when the bone cement (2), after collecting, is exposed to atmospheric pressure;
• and
• wherein the vacuum source (21) is connected to the front member (5).