A novel design of hip-stem with reduced strain-shielding
File(s)Manuscript_IMechE_final Amis 03 05 24.docx (2.82 MB)
Accepted version
Author(s)
Loha, Tanmoy
Bhattacharya, Rounak
Pal, Bidyut
Amis, Andrew A
Type
Journal Article
Abstract
The use of uncemented stems in hip arthroplasty has been increasing, even in osteoporotic patients. The major concerns of uncemented hip-stems, however, are peri-prosthetic fracture, thigh pain, and proximal femoral stress-/strain-shielding. In this study, a novel design of uncemented hip-stem is proposed that will reduce such concerns, improve osseointegration, and benefit both osteoporotic and arthritic patients. The stem has a central titanium alloy core surrounded by a set of radial buttresses that are partly porous titanium, as is the stem tip. The aim of the study was to investigate the mechanical behaviour of the proposed partly-porous design, examining load transfer in the short-term, and comparing its strain-shielding behaviour with a solid metal implant. The long-term effect of implant-induced bone remodelling was also simulated. Computed tomography based three-dimensional finite element models of an intact proximal femur, and the same femur implanted with the proposed design, were developed. Peak hip contact and major muscle forces corresponding to level-walking and stair climbing were applied. The proposed partly-porous design had approximately 50% lower strain-shielding than the solid-metal counterpart. Results of bone remodelling simulation indicated that only 16% of the total bone volume is subjected to reduction of bone density. Strain concentrations were observed in the bone around the stem-tip for both solid and porous implants; however, it was less prominent for the porous design. Lower strain-shielding and reduced bone resorption are advantageous for long-term fixation, and the reduced strain concentration around the stem-tip indicates a lower risk of peri-prosthetic fracture.
Date Issued
2024-05
Date Acceptance
2024-04-01
Citation
Proceedings of the Institution of Mechanical Engineers Part H: Journal of Engineering in Medicine, 2024, 238 (5), pp.471-482
ISSN
0954-4119
Publisher
SAGE Publications
Start Page
471
End Page
482
Journal / Book Title
Proceedings of the Institution of Mechanical Engineers Part H: Journal of Engineering in Medicine
Volume
238
Issue
5
Copyright Statement
© IMechE 2024. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/38644528
Subjects
Arthroplasty, Replacement, Hip
Femur
Finite Element Analysis
Hip Prosthesis
Humans
Materials Testing
Porosity
Prosthesis Design
Stress, Mechanical
Femur
fixation stem
hip prosthesis
osteoporosis
porous material
stress-shielding
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2024-04-21