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http://hdl.handle.net/10773/30474
Title: | Femoral revision knee Arthroplasty with Metaphyseal sleeves: the use of a stem is not mandatory of a structural point of view |
Author: | Fonseca, F. Sousa, A. Completo, A. |
Keywords: | Experimental strains Finite element model Metaphyseal sleeve Stress-shielding Total knee arthroplasty Revision Metaphyseal bony defects |
Issue Date: | 1-Dec-2020 |
Publisher: | SpringerOpen |
Abstract: | Purpose Metaphyseal sleeves are an option for patients with severe metaphyseal bony defects requiring TKA revision. Although sleeves are usually used with stems, little is known about the exact contribution/need of the stem for the initial sleeve-bone interface stability, particularly in the femur, if the intramedullary canal is deformed or bowed. It is hypothesised that diaphyseal-stem addition increases the sleeve-femur interface stability and the strain-shielding effect on the metaphyseal femur relatively to the stemless condition. Material and methods Synthetic-femur was used to measure cortex strain behaviour and implant cortex micromotions for three techniques: only femoral-component, stemless-sleeve and stemmed-sleeve. Paired t-tests were performed to evaluate the statistical significance of the difference between mean principal strains and implant-cortex micromotions. Finite-element models were developed to assess the cancellous-bone strain behaviour and sleeve-bone interface micromotions; these models were validated against the measurements. Results Cortex strains are reduced significantly (p<0.05) in 83% of strain gauges on stemmed-sleeve, which compares with 33% in stemless condition. Both techniques presented a cancellous bone strain reduction of 50% at the distal region and an increase of nearly four times at the sleeve proximal region relative to the model only with the femoral component. Both techniques presented sleeve-bone micromotions amplitude below 50-150μm, suitable for bone ingrowth. Conclusions The use of a supplemental diaphyseal-stem potentiates the risk of cortex bone resorption compared with the stemless-sleeve condition; however, the stem is not vital for increasing the initial sleeve-bone stability and has a minor effect on the cancellous-bone strain behaviour. Of a purely structural point view, appears that the use of a diaphyseal-femoral-stem with the metaphyseal sleeve is not mandatory in the revision TKA which is particularly relevant in cases where the use of stems is impracticable. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/30474 |
DOI: | 10.1186/s40634-020-00242-w |
ISSN: | 2197-1153 |
Appears in Collections: | TEMA - Artigos DEM - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Author Manuscript - Femoral revision knee Arthroplasty with Metaphyseal sleeves_the use of a stem is not mandatory of a structural point of view.pdf | 1.28 MB | Adobe PDF | View/Open |
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