Dimensional and thermal behaviour of calcium phosphate cements during setting compared to PMMA bone cements

摘要

The use of PMMA bone cements for the fixation of metal endoprostheses in hip and knee surgery is quite successful. However, the average lifetime of such provisions is limited to about 12 years, which according to some investigators is mainly due to the PMMA cement [1]. During setting these materials develop temperatures far above body temperature so that the adjacent bone tissue becomes necrotic. Furthermore, they shrink due to polymerization and thus allow for micromovements of the prosthesis directly after the operation. That the gap between bone and cement becomes filled with fibrous tissue after some time does not inhibit these micromove-ments. Often the combined effect of these events is formation of particular debris and ultimately loosen-ing of the prosthesis by osteolysis.