Fixation of knee alloplasties is done in 70% of cases with use of cement. It is uncertain whether there is a difference in the long-term survival of knee prostheses with the two types of cement used in this project. Both types of cement in this study are used today in knee surgery with good, short-term clinical results. It is important to investigate new types of cement in order to assure future patients the best possible results after knee alloplasty and fewer re-operations.