Abstract
Purpose: Implant loosening is a common complication that compromises the stability of joint replacement systems. Stem geometry is particularly influential in the stability of cemented implants, both before and after debonding occurs at the stem-cement interface. There are few studies assessing the effect of stem longitudinal curvature as a geometric factor in cemented implant stability. The purpose of this study was to compare the torsional stability of four generalized cemented implant stems (i.e., non-specific to joint), with varying degrees of longitudinal curvatures - zero, two, four, and six degrees. Methods: Twelve specimens of each curvature angle were potted to a depth of 20 mm using bone cement, given 24 hours to cure, and then tested in a materials testing machine. Torque was applied to the stems under monotonic loading at a rate of 2.5 degrees/min, until five degrees of rotation had occurred. Results: There were no differences in torsional stability among the four stem curvature angles, when the magnitudes of peak torque (P=.72; 1-β = 0.13), rotation of the stem at peak torque (P=0.23; 1-β = 0.38) and work required for five degrees of stem rotation (P=.58; 1-β = 0.07) were compared. Conclusions: The findings from this study demonstrate that for short stems, stem curvature angles up to six degrees does not improve torsional stability when compared to the straight stem design.
J Appl Biomater Funct Mater 2013; 11(3): 167 - 171
Article Type: ORIGINAL RESEARCH ARTICLE
DOI:10.5301/JABFM.2012.9266
Authors
Yara K. Hosein, Meghan P. Clynick, Stewart D. McLachlin, Graham J.W King, Cynthia E. Dunning
Article History
- • Accepted on 02/03/2012
- • Available online on 22/06/2012
- • Published online on 16/12/2013
This article is available as full text PDF.
Authors
- Hosein, Yara K.
[PubMed]
[Google Scholar]
Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON - Canada
- Clynick, Meghan P.
[PubMed]
[Google Scholar]
Department of Materials & Mechanical Engineering, The University of Western Ontario, London, ON - Canada
- McLachlin, Stewart D.
[PubMed]
[Google Scholar]
Department of Materials & Mechanical Engineering, The University of Western Ontario, London, ON - Canada
- King, Graham J.W
[PubMed]
[Google Scholar]
Department of Surgery, The University of Western Ontario, London, ON - Canada
- Dunning, Cynthia E.
[PubMed]
[Google Scholar]
Biomedical Engineering Graduate Program, The University of Western Ontario, London, ON - Canada; Department of Materials & Mechanical Engineering, The University of Western Ontario, London, ON - Canada and Department of Surgery, The University of Western Ontario, London, ON - Canada
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