The invention relates to a mixing device for polymethylmethacrylate bonecements(PMMA bone cements), comprising a mixing space (2) for mixing the PMMA bonecement at least one mixing element (4) supported in the mixing space (2) suchthat itcan rotate a gear, by means of which the rotation of the at least one mixingelement (4)can be driven at least one elastically deformable energy-storing element (16)that isconnected to the gear such that the gear can be driven by an elastic energyfrom theenergy-storing element (16) and such that the at least one mixing element (4)can berotated in the mixing space (2) by means of the gear upon the release ofelastic energyfrom the energy-storing element (16).The invention further relates to a vacuum mixing system comprising a mixingdevice ofthis type and to a method for mixing a cement, in particular a PMMA bonecement.
