Bioactive cement or ceramic/porous coating vs. conventional cement to obtain early stability of the acetabular cup. Randomised study of 96 hips followed with radiostereometry.

Ninety patients (96 hips) scheduled for THA were stratified to fixation of the acetabular component in three main groups of about equal size. Fluoride cement, porous coated press-fit cup with ceramic coating or Palacos cum Gentamicin cement were used. All patients received Spectron EF stem. The migration of the cups and the femoral head penetration into the socket were measured with radiostereometric analysis. At 2 years the choice of fixation did not influence the migration or rotation of the cup. Patients with compromised bone quality showed increased three-dimensional (3D or total) migration. Proximal and 3D penetration rates were increased in cemented compared with the uncemented cups (p<0.001), which probably not could be related to the choice of fixation. Appearance of radiolucent lines was almost equal in the two cemented groups. Uncemented cups had less radiolucent lines at 2 years. Fluoride containing cement or uncemented fixation did not improve the early postoperative stability of the socket.