In-vitro wear measurement of total knee replacement using tibial polyethylene inserts in combination with ceramic and metallic femoral components under abrasive three body wear conditions

INTRODUCTION: Due to increased life expectancy at human population the amount of osteoarthritis of the knee joint will increase. The total knee replacement (TKR) is often the only way to achieve analgesia, to establish the joint function and to correct joint deformation. TKR reached a high grade of quality and safety and has become an often used surgical procedure [1]. TKR most often fail due to aseptic implant loosening. In the absence of infection, aseptic loosening may occur due to the biological response of the bone to stress shielding, micro motion or biological loosening due to osteolysis. It is believed that polyethylene (PE) wear debris, generated at the articulating surfaces, leading to osteolysis and loosening of endoprosthesis [2]. Therefore the prior aim is to minimize the generation of wear debris by providing low-wear bearings. Beside wear caused by adhesion, surface damage and wear can also be caused by three body particles. De Baets et al. showed that 42% of the debris left in situ are bone cement particles which can damage the surfaces and induce wear [3]. The objective of this experimental study was to evaluate the wear of the tibial PE insert of the total knee endoprosthesis system Multigen Plus CR with metallic and ceramic femoral components at three body wear situation induced by polymethylmethacrylate (PMMA) and zirconia (ZrO2) particles from bone cement. For gait simulations a knee joint wear simulator according to ISO 14243 were used. Previous experimental studies show less wear of PE/ceramic couplings in comparison to PE/metallic because of the low friction of ceramic surface [4]. Moreover, the incidence of allergic reaction against metallic implant materials increases [5]. Hence, allergic-free implants could improve the long term survival rate of total knee endoprosthesis. Biological inert implants consisting of ceramics could offer an alternative solution to patients with sensitivity to metals [6].