Abstract:
Little is known about tibial bone remodeling with TKA and its clinical relevance. We performed a randomized clinical trial to compare tibial bone density changes in cemented components with different bearing designs. Bone density changes were assessed using quantitative computed tomography (qCT)-assisted osteodensitometry. Twenty-eight rotating-platform and 26 fixed-platform cemented TKAs were included. The nonoperated contralateral side was used as a control. CT scans were performed postoperatively and 1 year and 2 years after the index operation. Cancellous bone density loss (up to 12.6% at 2 years) was observed in all proximal tibial regions in both cohorts. In contrast, we found lower cortical bone density loss (up to 3.6% at 2 years). We found no differences in bone loss between fixed- and rotating-platform implants. The decrease of cancellous bone density after TKA suggests stress transfer to the cortical bone. One or more of the authors (JTM, MC, RPP) have received funding from unrestricted educational grants from the Wishbone Trust New Zealand and the Stevensons Trust New Zealand. The study was partially funded by DePuy International, Leeds, UK. Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This work was performed at University of Auckland.