35 research outputs found

    Diet in irritable bowel syndrome

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    Metal-on-Metal Compared With Metal-on-Polyethylene: The Effect on Trunnion Corrosion in Total Hip Arthroplasty

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    © 2017 Elsevier Inc. Background Trunnion tribocorrosion in total hip arthroplasties is concerning, but retrieval studies often are subjective or lack comparison groups. Quantitative comparisons of clinically relevant implants are required. The purpose of this investigation was to evaluate material loss in metal-on-metal (MoM) and metal-on-polyethylene (MoP) total hip articulations while controlling for trunnion design and head size. Methods The 166 retrieved femoral heads from 2 manufacturers were analyzed. Four cohorts based on head size, trunnion design, manufacturer, and articulation type (MoM vs MoP) were created. Corrosion was measured by a coordinate measurement machine, and material loss was assessed (MATLAB). Results Retrieved femoral heads from MoP articulations had 5 times less trunnion material loss than MoM articulations, on average, for both manufacturers. There was no difference in material loss between large modular head (\u3e40 mm) and 36-mm MoM hip trunnion. Implants with a material loss above the detectable limit demonstrated a correlation with time in vivo only in MoP articulations. Conclusion Retrieved femoral heads from MoP bearing couples had a lower magnitude of material loss than MoM couples, independent of head diameter. A time in vivo effect was only seen in MoP bearings

    The effect of altering head length on corrosion using a material loss method

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    © The Author(s) 2018. Introduction: Corrosion at head neck taper junctions in total hip arthroplasty has increasingly been reported in the literature. Debate persists as to the exact causes and clinical significance of corrosion. Increased offset and head length has been correlated with an increased risk of tribocorrosion due to an adverse mechanical environment. The purpose of this study is to assess the effect of head length on corrosion of a metal-on-polyethylene articulation. Methods: Retrievals from a single institution of 28-mm cobalt chromium alloy heads with a 12/14 taper from a single manufacturer were studied. Corrosion of femoral head bores were studied utilising a material loss method. Testing was performed using co-ordinate measuring for maximum linear wear depth. Results: 56 heads were examined with lengths of either −3, 0, +4 or +8 mm and all had been in situ for a minimum of 2 years. There were no significant differences in mean maximum linear wear depth (MLWD) (p = 0.6545). There was no correlation found between MLWD and the time implants were in situ (Spearman coefficient −0.1157) and no significant difference seen between high or standard offset stems (p = 0.1336). Conclusion: In contrast to studies using qualitative methodologies, there was no correlation between head length and material loss when confined to a 28-mm head. Broad application of this outcome should be cautioned against as this study examined 1 taper construct and a metal-on-polyethylene articulation
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