Cemented tibial tray fixation

Although a successful surgical intervention, total knee arthroplasty resulted in about 25 000 revision procedures in 2013 in Germany. The majority of cases concern the tibial component of the prosthesis. Avoidance or at least postponement of revision surgery is desirable in order to decrease infection risk and bone loss related to implant extraction. In up to one third of the cases the reason for revision is aseptic loosening, which is caused by poor implant fixation. Fixation is typically performed using bone cement that forms an interlock with the trabecular bone. An indicator for the fixation strength is pull-out strength, which has been shown to correlate to penetration depth of the cement into the bone. Considering the interlock connection, the architecture of trabecular bone may play a role in fixation strength. The trabecular architecture is patient- and location-dependent, requiring patient-specific analysis. The aim of this thesis was to improve interlock between cement and bone. This goal was achieved by investigation of cement layer morphology in cadaveric specimens. The influence of cement penetration depth, cementation technique, as well as of bone density and porosity on fixation strength was analysed using computed tomography image analysis, mechanical pull-out testing and statistical modelling of fixation strength by regression. Investigated cementation techniques were gun and manual application, full and plateau-only cementation, two-layered cementation and bone cleansing using pulsatile or syringe lavage.