Corrosion at the head-neck taper interface of artificial hip joints

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Date
2013-06, 2015-01
Authors
Dyrkacz, Richard Michael Ryan
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Arthroplasty
Tribology International
Abstract
The aim of this thesis was to determine if the size of the femoral head can influ-ence corrosion at the head-neck taper interface of total hip arthroplasty (THA) prosthe-ses. A hypothesis was developed that large head sizes could result in a greater toggling torque at the head-neck taper interface by increasing the distance between the centre of the femoral head to the centre of the neck taper. This could result in increased micromotion and deteriorate the passive oxide film along the head-neck taper interface; thus, making the taper interface vulnerable to corrosion. A retrieval analysis of 74 THA prostheses studied the corrosion damage at the head-neck taper interface. This study revealed that prostheses featuring 36 mm femoral heads had significantly greater head taper corrosion than prostheses with a 28 mm head. Finite element analysis was performed afterwards to identify if the use of large femoral heads can increase the micromotion at the head-neck taper interface due to a greater toggling torque. This experiment demonstrated that with a larger head size the micromotion at the head-neck taper interface increases. An in vitro corrosion fatigue study was performed afterwards following ASTM F1875-98. When applying an off-axis fatigue load, prostheses featuring a 36 mm femoral head displayed significantly more corrosion damage at the head-neck taper interface than those with a 28 mm femoral head. Axial fatigue loading was also applied; negligible corrosion damage at the head-neck taper interface was discovered in comparison to the prostheses that received an out of axis load. This verifies that the use of large femoral heads can result in increased head-neck taper corrosion due to a greater toggling torque.
Description
Keywords
Corrosion, Fretting, Total Hip Arthroplasty, Finite Element Analysis
Citation
R. M. R. Dyrkacz, J. M. Brandt, O. A. Ojo, T. R. Turgeon, and U. P. Wyss, "The influence of head size on corrosion and fretting behaviour at the head-neck interface of artificial hip joints," Journal of Arthroplasty, vol. 28, pp. 1036-1040, 2013.
R. M. R. Dyrkacz, S. T. O'Brien, J. M. Brandt, J. B. Morrison, O. Ojo, T. R. Turgeon, et al., "Finite element analysis at the head-neck taper interface of modular hip prostheses," Tribology International, vol. Currently in press, 2015.