A comparison between cemented, press-fit, and HA-coated interfaces in Kinemax total knee replacement

There are possible advantages of using uncemented fixation in total knee replacement. In this prospective randomised multi-centre study, a comparison was made between cemented and two types of uncemented fixation for the Kinemax design. There were 12–14 cases in each group. Beads were inserted in the bones from which component migration was measured at time intervals up to 2 years. The axial migrations were significantly less for cemented and HA-coating, compared with press-fit, at all time intervals. The clinical data showed no differences at 2 years except for more cases of pain in the uncemented groups. Radiographically, the cemented interfaces showed the least change, press-fit showed a radiolucent line and a radiodense line, and HA showed a diffuse radiodensity adjacent to the components. It was concluded that for the Kinemax design of tibial component, press-fit was inferior to cemented, but that there was the potential for designing a special component for uncemented fixation for which HA-coating would be an advantage.