TY - JOUR
T1 - The relation between micromotion and screw fixation in acetabular cup
AU - Hsu, Jui Ting
AU - Lai, Kuo An
AU - Chen, Qingshan
AU - Zobitz, Mark E.
AU - Huang, Heng Li
AU - An, Kai Nan
AU - Chang, Chih Han
N1 - Funding Information:
This research was supported by the grant no. NSC 92-2320-B-006-067 from the National Science Council, Taiwan, Republic of China.
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2006/10
Y1 - 2006/10
N2 - One of the major causes inducing loosening in the cementless acetabular cup implanting is its insufficient initial stability. In this study, three-dimensional finite element models of the pelvis and acetabular components were developed to investigate the relationship between relative micromotion, initial stability, and screw fixation under six daily activity loadings. A commercial available hemispheric cup with five screw holes was used as the target acetabular cup. The simulation results showed that if screws were placed closed together, when the screw number increased from 1 to 5, the peak micromotion decreased less than 14%, from 126.5 to 108.8 μm, while the stable region, micromotion less than 28 μm, enlarged only by 40%, from 46.1% to 64.7%. However, if the screw could be placed near the cup rim, a single rim screw, 202.1 μm micromotion, could provide better stability than that of four dome screws, 209.6 μm micromotion, placed closed together. To conclude, multiple cup screws should be placed near cup rim and as separate as possible to enlarge the stable region and reduce the peak micromotion between cup and acetabulum.
AB - One of the major causes inducing loosening in the cementless acetabular cup implanting is its insufficient initial stability. In this study, three-dimensional finite element models of the pelvis and acetabular components were developed to investigate the relationship between relative micromotion, initial stability, and screw fixation under six daily activity loadings. A commercial available hemispheric cup with five screw holes was used as the target acetabular cup. The simulation results showed that if screws were placed closed together, when the screw number increased from 1 to 5, the peak micromotion decreased less than 14%, from 126.5 to 108.8 μm, while the stable region, micromotion less than 28 μm, enlarged only by 40%, from 46.1% to 64.7%. However, if the screw could be placed near the cup rim, a single rim screw, 202.1 μm micromotion, could provide better stability than that of four dome screws, 209.6 μm micromotion, placed closed together. To conclude, multiple cup screws should be placed near cup rim and as separate as possible to enlarge the stable region and reduce the peak micromotion between cup and acetabulum.
KW - Acetabular cup
KW - Finite element methods
KW - Initial stability
KW - Screw fixation
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U2 - 10.1016/j.cmpb.2006.08.002
DO - 10.1016/j.cmpb.2006.08.002
M3 - Article
C2 - 16971018
AN - SCOPUS:33748807200
SN - 0169-2607
VL - 84
SP - 34
EP - 41
JO - Computer Methods and Programs in Biomedicine
JF - Computer Methods and Programs in Biomedicine
IS - 1
ER -