Effect of tibial tray design on cement morphology in total knee arthroplasty

BACKGROUND Improvements to enforce primary fixation in cemented total knee arthroplasty have been suggested to be a key issue for long-term survival. In this context, it has been questioned whether specific implant design features influence bone cement morphology and hence primary interface strength. The purpose of this study was to investigate in vitro the influence of cement pockets on the tibial tray on cement penetration in the tibia. METHODS Eight paired cadaveric, human tibiae were available for investigation. One side of a pair was implanted with a fixed bearing tibial tray (FB) featuring cement pockets on the undersurface, while in the other side, a mobile bearing platform (MB) without cement pockets was used. Specimens underwent computed tomography analysis of the cement morphology as well as BMD assessment. RESULTS While bone cement layer between implant and bone surface was thicker in the FB group (p = 0.032), bone cement penetration was not influenced by implant design (p = 0.529). CONCLUSIONS The present study suggests that cement pockets do not alter or enforce bone cement penetration under the tibial tray in an in vitro scenario.