In vivo and in vitro outcomes of alumina, zirconia and their composited ceramic-on-ceramic hip joints

Despite of brittleness, Ceramic-on-Ceramic (CoC) hip joints are appealing to arthritic patients because of its low friction rate, high wear resistance and low risk of osteolysis. The objectives of the study were to review and summarize the performance of Alumina, Zirconia and their functional graded material (FGM) for artificial hip joints in vivo and vitro outcomes. The Method of the study was scoping review which focused on the peer reviewed journals containing with alumina, zirconia and alumina zirconia FGM to CoC hip prosthesis. Advanced version of Alumina CoC was found to have excellent hardness but low fracture toughness. Alumina CoC hip joints was found to have a revision rate as high as 5% after 20 clinical outcomes. Zirconia ceramic had high fracture toughness but relatively low hardness when compared to Alumina ceramic. Alumina-Zirconia FGM consists both high hardness (outer surface) and improved fracture toughness (inner core) which led to better mechanical and tribological properties. However, to date, there is still no literature was found to have long period of clinical outcomes. No article was screened carrying out durability study of Alumina/Zirconia FGM for CoC hip joints with appropriate tribological experiment. Alumina/Zirconia FGM could be very effective for long term durability of CoC hip joints. Nevertheless, this FGM needs to be investigated under appropriate tribological tests considering dynamic loadings, dimension and shape of the joints, lubricant similar to synovial fluid and large number of cycles. The long term clinical outcomes also need to be published to increase its acceptability to young active patients. (C)2013 The Ceramic Society of Japan. All rights reserved.