Comparison of a novel porous titanium construct (Regenerex) to a well proven porous coated tibial surface in cementless total knee arthroplasty - A prospective randomized RSA study with two-year follow-up

Background: Regenerex is a novel porous titanium construct with a three-dimensional porous structure and biomechanical characteristics close to that of normal trabecular bone. The aim of this study was to compare this novel construct to a well-proven porous plasma sprayed tibial (PPS) implant after total knee arthroplasty. Methods: Sixty-one patients scheduled for an uncemented TKA were randomized to receive either a novel highly porous titanium construct Regenerex or the PPS tibial component. Radiostereometric analysis of the tibial components was performed postoperatively and at three, six, 12, and 24 months with measurements of migration (segment motion and maximum total point motion (MTPM)). Results: Knee and function scores improved significantly from preoperatively to two-year follow-up. For both the Regenerex and the PPS the majority of migration appeared during the first three months and then stabilized. No statistically significant differences in MTPM were found in any follow-up between three and 24 months. The Regenerex group had a lower migration rate between 12 and 24 months compared with the PPS implants (p = 0.03) but the PPS group had an initial significantly lower subsidence (p = 0.04). Conclusion: In conclusion the Regenerex implant could prove an effective scaffold material for coating of uncemented implants but did no better than the PPS component at 24 months of follow-up. ClinicalTrials.gov identifier: NCT01936415. (C) 2016 Published by Elsevier B.V.