BACKGROUND: The normal-curing Refobacin® Bone Cement R (RR) and slow-curing Refobacin® Plus Bone Cement (RP) were introduced after discontinuation of the historically most used bone cement, Refobacin®-Palacos® R, in 2005. The aim of this study was to compare total knee arthroplasty component fixation with the two bone cements.
METHODS: 54 patients with primary knee osteoarthritis were randomized to either RR (N = 27) or RP (N = 27) bone cement and followed for two years with radiostereometric analysis of tibial and femoral component migration and dual-energy x-ray absorptiometry measured periprosthetic bone mineral density (BMD). Further, patients were followed up at ten years with clinical outcome scores (OKS and KOOS).
RESULTS: At two-years follow-up, tibial total translation was 0.31 mm (95% CI: 0.19 - 0.42) for the RP group and 0.56 mm (95% CI: 0.45 - 0.67) (p < 0.01) for the RR group. There was continuous tibial component migration from one to two years follow-up (MTPM > 0.2 mm) in 13/27 patients from the RR and in 12/26 patients from the RP group. There was no difference between groups in BMD baseline values or changes during follow-up, as well as no correlation between change in BMD and tibial component migration. At ten-years follow-up, the improvement in the clinical outcome scores was similar between groups. There were no prosthesis related complications during the 10-year follow-up.
CONCLUSION: At two years, tibial total translation was lower in the RP compared with the RR cement group, but BMD changes were similar. At ten years, no components were revised and clinical outcome scores were similar between groups.