Browne, M., Jeffers, J.R.T. and Saffari, N.
Nondestructive evaluation of bone cement and bone cement/metal interface failure.
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 92B, . (doi:10.1002/jbm.b.31530).
To quantify the failure mechanisms related to the loosening of cemented hip joint
replacements, novel techniques, capable of monitoring, nondestructively, the initiation and
progression of failure during in vitro fatigue tests, were employed. Fatigue testing of model
cement and cement-stem test pieces was monitored using acoustic emission (AE) sensors. Once
damage was detected, an ultrasonic imaging system was used to obtain an image of the damage
site and to measure the stiffness of the affected region. This method of examination provided a
detailed insight into the internal crack propagation and delamination patterns. Initial work
was conducted on bulk cement specimens subjected to bending and tension. The second stage
of the work examined a model stem-cement interface under tensile opening loading conditions.
A novel ultrasonic technique was used to measure the bond quality at the cement-metal
interface. Progressive delamination was identified over time, and the AE technique was able to
identify critical areas of delamination before they could be identified conclusively by
ultrasonic imaging. The work has demonstrated the potential of the AE technique as a tool for
the preclinical assessment of total hip replacements.
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