Key-properties and Recent Advances In Bone Cements Technology

VAZQUEZ,B.; ABRAHAM,G.A.; ELVIRA,C.; GALLARDO,A.; SAN ROMAN,J

Polymer Based Systems on Tissue Engineering, Replacement and Regeneration. NATO-ASI Science series.

Kluwer Academic Publishers

Lugar: No Informado; Año: 2002; p. 69 - 92

At the beginning of the 60’s decade Sir John Charnley presented the preliminary results of a new method for bone prosthesis fixation based on the load distribution between the bone and the implant by a filling compound called bone cement which is basically autopolymerizable PMMA. This technique has been accepted worldwide in the fixation of knee and hip prosthesis giving excellent results, but in some cases, revisions and prosthesis replacement are required with the corresponding social and economical costs. The main advantages of bone cemented prosthesis rely on the excellent primary fixation between bone and implant and, consequently, in a faster patient recuperation. It is also a low damaging and facile technique to be applied as the bone cements are easily moulded and well adapted to bone complex cavities. However, the technique presents disadvantages such as long-term prosthesis loosening as a consequence of the absence of secondary fixation of the cement. Moreover, the polymerization reaction of methyl methacrylate, MMA, is highly exothermic, and can provoke cellular necrosis in the surrounding tissues. It has also to be considered the toxicity of the aromatic tertiary amine used in these formulations to activate the initiation of the polymerization process. Taking into consideration theses aspects, it has to be pointed out that the cementing technique balance is highly positive. Its effectiveness is total after approximately 7 years of implantation and it is reduced to 80% after 15 years, in comparison to the non-cemented prosthesis. These statistics clinical experiences are based on revisions carried out in hospitals worldwide in which new surgical intervention has been performed in periods of 20 years time. The results concluded that non-cemented prosthesis (Al2O3, metal-metal, or hydroxyapatite plasma spray prosthesis) present effectiveness much lower than cemented ones, over short and long periods of time. Several research groups are involved in projects to avoid the bone cements disadvantages and to develop new improvements, which are presented in this chapter. Keywords: acrylic bone cements; acrylic formulations; bone cement technology; hip prosthesis.