Cemented Marathon/Corail Versus Pinnacle/Corail

A randomised, comparative, prospective, single-blinded trial of two hip prosthesis: 1. Marathon cemented all-poly acetabular cup(Depuy, Warsaw, Indiana), Corail uncemented femoral stem(Depuy, Warsaw, Indiana), 32mm Alumina Biolox Forte femoral head(Depuy, Warsaw, Indiana) and 2. Pinnacle/Marathon uncemented cup(Depuy, Warsaw, Indiana), Corail uncemented femoral stem(Depuy, Warsaw, Indiana), 32mm Alumina Biolox Forte femoral head(Depuy, Warsaw, Indiana) There will be a further in-group randomisation to a Corail femoral stem with or without a collar, creating a number of 4 study-groups in total. The aims of the study are: * To compare polyethylene wear and migration of the moderately cross-linked Marathon polyethylene in a cemented version(Marathon) and in an uncemented cup(Pinnacle/Marathon) * To evaluate micromigration and periacetabular bone mineral density of the 2 cups using radiostereometry(RSA) * To evaluate the migration patterns and proximal femoral bone density changes around the Corail stems with and without a collar