ABSTRACT
BACKGROUND: The objectives of this study are to (1) evaluate if there is a potential difference in cemented implant fixation strength between tibial components made out of cobalt-chromium (CrCoMo) and of a ceramic zirconium nitride (ZrN) multilayer coating and to (2) test their behavior with 5 different bone cements in a standardized in vitro model for testing of the implant-cement-bone interface conditions. We also analyzed (3) whether initial fixation strength is a function of timing of the cement apposition and component implantation by an early, mid-term, and late usage within the cement-specific processing window. METHODS: An in vitro study using a synthetic polyurethane foam model was performed to investigate the implant fixation strength after cementation of tibial components by a push-out test. A total of 20 groups (n = 5 each) was used: Vega PS CrCoMo tibia and Vega PS ZrN tibia with the bone cements BonOs R, SmartSet HV, Cobalt HV, Palacos R, and Surgical Simplex P, respectively, using mid-term cement apposition. Three different cement apposition times-early, mid-term, and late usage-were tested with a total of 12 groups (n = 5 each) with the bone cements BonOs R and SmartSet HV. RESULTS: There was no significant difference in implant-cement-bone fixation strength between CrCoMo and ZrN multilayer-coated Vega tibial trays tested with 5 different commonly used bone cements. CONCLUSION: Apposition of bone cements and tibial tray implantation in the early to mid of the cement-specific processing window is beneficial in regard to interface fixation in TKA.