|Publisher DOI:||10.1243/095441105X69150||Title:||Deformation of press-fitted metallic resurfacing cups. Part 1: Experimental simulation||Language:||English||Authors:||Jin, Zhongmin
Parsons, Peter A.
Isaac, Graham H.
|Keywords:||Arthroplasty, Replacement, Hip;Biocompatible Materials;Cadaver;Elasticity;Equipment Design;Equipment Failure Analysis;Hardness;Hardness Tests;Humans;In Vitro Techniques;Materials Testing;Metals;Pressure;Prosthesis Design;Surface Properties;Hip Prosthesis;Prosthesis Failure||Issue Date:||1-Feb-2006||Source:||Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine 2 (220): 299-309 (2006)||Journal or Series Name:||Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine||Abstract (english):||The interference press fit of a metallic one-piece acetabular cup employed for metal-on-metal hip resurfacing procedures was investigated experimentally under laboratory conditions in the present study, in particular regarding the cup deformation. Tests were carried out in cadavers as well as polyurethane foams of various grades with different elastic moduli to represent different cancellous bone qualities. The cadaver test was used to establish the most suitable configuration of the foam model representing realistic support and geometrical conditions at the pelvis. It was found that a spherical cavity, with two identical areas relieved on opposite sides, was capable of creating a two-point pinching action of the ischeal and ilial columns on the cup as the worst-case scenario. Furthermore, the cup deformation produced from such a two-point loading model with a grade 30 foam was similar to that measured from the cadaver test. Therefore, such a protocol was employed in subsequent experimental tests. For a given size of the outside diameter of the cup of 60 mm, the cup deflection was shown to be dependent largely on the cup wall thickness and the diametral interference between cup and prepared cavity at implantation. For a relatively thin cup with a wall thickness between 2.3 mm (equator) and 4 mm (pole) and with a modest nominal diametral interference of 1 mm, which corresponds to an actual interference of approximately 0.5 mm, the maximum diametral cup deflection (at the rim) was around 60 microm, compared with a diametral clearance of 80-120 microm between the femoral head and the acetabular cup, generally required for fluid-film lubrication and tribological performances. Stiffening of the cup, by both thickening and lateralizing by 1 mm, reduced the cup deformation to between 30 and 50 microm with actual diametral interferences between 0.5 and 1 mm.||URI:||http://tubdok.tub.tuhh.de/handle/11420/1605||DOI:||10.15480/882.1602||ISSN:||2041-3033||Institute:||Biomechanik M-3||Type:||(wissenschaftlicher) Artikel||Permission Note:||Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich. This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.||License:||In Copyright|
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