Comparison of Refobacin bone cement and palacos with gentamicin in total hip arthroplasty: an RSA study with two years follow-up.

Previous experience has demonstrated the importance of testing new bone cement in vivo before widespread clinical use. We performed a consecutive, radiostereometric (RSA) study comparing Refobacin Bone Cement (RBC) to the well proven Palacos with Gentamicin (PWG). According to the manufacturer of RBC it has the equivalent characteristics as PWG, and in vitro tests show good results. The purpose of this study was to evaluate whether RBC is safe to use in clinical practice for total hip arthroplasty (THA). Two consecutive series of patients with primary osteoarthritis received a THA using a highly polished, collarless, tapered stem with a hollow centralizer. The study comprises 21 hips with RBC and 30 with PWG. The patients were followed up for two years with repeated RSA examinations and clinical outcome questionnaires SF-12 and WOMAC. There were no statistically significant migratory differences between the groups. The mean subsidence after two years was 1.28 mm and 1.40 mm, and the mean retroversion was 1.03° and 0.99°, for the RBC and the PWG groups respectively. Almost all migration occurred in the interface between the stem and the cement. The WOMAC and SF12 clinical scores did not reveal any clinical differences between the groups. We conclude that, as previous in vitro tests indicate, RBC performs as well as PWG and seems to be safe to use in clinical practice for THA.