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Biomechanics of short hip endoprostheses - The risk of bone failure increases with decreasing implant size
Publikationstyp
Journal Article
Date Issued
2010-08-01
Sprache
English
Author(s)
Journal
Volume
25
Issue
7
Start Page
666
End Page
674
Citation
Clinical Biomechanics 25 (7): 666-674 (2010)
Publisher DOI
Scopus ID
Publisher
Elsevier
Background: Short uncemented metaphyseally anchored femoral endoprostheses are becoming popular and are proposed to be less invasive than longer conventional implants. However, it is proposed here that shortening femoral endoprostheses can increase the risk of periprosthestic fracture. Methods: A simple analytical model of a femoral hip implant was developed to estimate the risk of bone overload for varying implant size, implantation geometry, implantation force and bone quality. The load capacity of a particular short implant design in poor quality cadaveric bone specimens was also measured experimentally, to validate the model. Findings: The model demonstrated a high risk of bone overload for a short endoprosthesis in poor quality bone. The experimental results and a clinical example of failure, to which the model was applied, supported this finding. Bone stresses increased with decreasing implant length and diameter, varus implantation, incomplete seating and high implantation forces, approaching the strength of good quality bone in extreme cases. Interpretation: Correct implantation and patient selection is essential for short femoral endoprostheses.
Subjects
Bone fracture
Experiment
Hip prosthesis
Metaphyseal
Model
DDC Class
610: Medicine, Health