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.