Influence of bone morphological properties on a new expandable orthopaedic fastener

M. Oldakowski, I. Oldakowska, T.B. Kirk, C.T. Ford, Tim B. Sercombe, P. Hardcastle, R.E. Day

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© Published under licence by IOP Publishing Ltd.Previous studies have demonstrated that bone morphological properties are a significant determinant of orthopaedic fastener fixation strength. The authors previously tested a new design of unthreaded expandable fastener (UEF) prototype against screws and demonstrated a significant increase in pull-out strength. However the effect of bone morphology on the pull-out strength of the UEF and expandable fasteners in general is unknown. This study assessed the correlation between failure force and maximum force against five microstructural parameters. The failure force of the UEF was correlated to the trabecular bone volume fraction, as with screws. Unlike screws, however, the maximum force of the UEF has an inverse relationship with cortical volume. No correlation was found between failure force and the Structural Model Index (SMI). Additionally the critical volume of interest (VOI) for the UEF is around the bottom of the fastener where the expansion occurs, whereas for the screw a full height VOI is critical. Furthermore, we observed that screw mechanical performance may be affected more by bone morphological parameters that are associated with poorer quality bone. Therefore the UEF may perform better than screws in low quality osteoporotic bone.
Original languageEnglish
Title of host publicationJournal of Physics: Conference Series
Subtitle of host publication13th South-East Asian Congress of Medical Physics
EditorsF Haryanto, K Ng, A Peralta, H Arimura , S Viridi
PublisherInstitute of Physics Publishing
ISBN (Print)17426588
Publication statusPublished - 2016
Event13th South-East Asian Congress of Medical Physics: SEACOMP 2015 - Yogyakarta, Indonesia
Duration: 10 Dec 201512 Dec 2015


Conference13th South-East Asian Congress of Medical Physics


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