The use of complementary non-destructive evaluation methods to evaluate the integrity of the cement–bone interface

The integrity of the cement–bone interface is vital to the long-term stability ofcemented hip arthroplasty. Most of the previous studies investigating the interface have beenconfined to the continuum level, neglecting the effects of microstructure. Microscopic damageat the interface may eventually lead to macroscopic loosening of the implant. However, sincethe strength of the interface depends on the interlock of the cement with bone and since theproperties of cancellous bone depend on its microstructure, the study of the behaviour of theinterface at the microstructural level may help an understanding of the factors governinginitiation of loosening to be gained. In this study, two complementary non-destructivemethods, acoustic emission (AE) and computed tomography (CT), have been implemented tostudy the initiation and progression of damage of an analogue cement–bone interface sampleunder four-point bending. Early failure was detected, localized, and characterized using AE. CTimages of the sample before and after loading were used to visualize damage in threedimensions. Damage initiated at the interface and was found to be related to stress-raisingmicrostructural features in the cement. These were caused by irregularities in the geometry ofthe bone analogue and recesses and notches formed by the flow of cement