Once-weekly oral medication with alendronate does not prevent migration of knee prostheses A double-blind randomized RSA study

Abstract

Background and purpose Early migration of joint replacements is an effect of poor fixation and can predict late loosen-ing. By reducing the bone resorption after implantation of a joint replacement, it should be possible to enhance the initial fixation of the implant. We studied the effect of once-weekly treatment with alendronate after knee replacement. Patients and methods We recruited 60 patients (60 knees) with gonarthrosis who were scheduled for a total knee replacement. They were operated on with identical implants and uncemented fixation. 30 patients were treated with a bisphosphonate (alendro-nate) and 30 patients underwent placebo treatment. The treatment started postoperatively and continued on a weekly basis for 6 months. The fixation of the implants was measured with repeated radiostereometry for 2 years. Results There was no difference in migration of implants between the two groups. Conclusion With uncemented fixation of knee implants, no benefit of once-weekly treatment with alendronate, starting post-operatively, could be seen during a 2-year follow-up period.