High vacuum as a method of reducing porosity of polymethylmethacrylate.

In total hip arthroplasty, fracture and subsequent premature loosening are directly related to the strength of the cement mantle serving as an interface between bone and prosthesis. The cement has been shown to be weakened by its porosity, which enhances the formation of microfractures that contribute to crack propagation. By means of a vacuum mixing method for preparing the cement, nearly all the porosity can be removed and cement strength enhanced by about 17%.