'Pre-launch' finite element analysis of a short-stem total hip arthroplasty system consisting of two implant types.
Bone remodeling
Finite element analysis
Short-stemmed implant
Total hip arthroplasty
Journal
Clinical biomechanics (Bristol, Avon)
ISSN: 1879-1271
Titre abrégé: Clin Biomech (Bristol, Avon)
Pays: England
ID NLM: 8611877
Informations de publication
Date de publication:
01 2019
01 2019
Historique:
received:
18
02
2018
revised:
03
11
2018
accepted:
06
11
2018
pubmed:
21
11
2018
medline:
12
2
2020
entrez:
21
11
2018
Statut:
ppublish
Résumé
We applied a previously established and validated numerical model to a novel short-stemmed implant for a 'pre-launch' investigation. The implant system consists of two different implant geometries for valgus/varus-positioned proximal femurs with differences in volume distribution, head/neck angle, and calcar alignment. The aim of the design was to achieve a better adaption to the anatomic conditions, resulting in a favourable load transfer. The implant type G showed the best fit to our model, but both stem geometries were implanted; the implant type B was used to compute an 'imperfection scenario'. Apparent bone density decreased by 4.3% in the entire femur with the implant type G, and by 12.3% with the implant type B. Bone mass loss was pronounced in the proximal calcar region. Apparent bone density increased at the lateral cortical ring and in the minor trochanter. The apparent bone density in the imperfection scenario was very similar to that of a straight stem, indicating a distal load transfer. No adverse effects of the A2 short-stemmed implant system on bone remodeling could be detected. The overall bone density reduction was acceptable, and wedge fixation was not observed, indicating that there was no distal load transfer. The simulation of an incongruous implant indicates the sensitivity of our model in response to modifications of implant positioning. Correct implant selection and positioning is crucial when using the A2 system.
Sections du résumé
BACKGROUND
We applied a previously established and validated numerical model to a novel short-stemmed implant for a 'pre-launch' investigation.
METHODS
The implant system consists of two different implant geometries for valgus/varus-positioned proximal femurs with differences in volume distribution, head/neck angle, and calcar alignment. The aim of the design was to achieve a better adaption to the anatomic conditions, resulting in a favourable load transfer. The implant type G showed the best fit to our model, but both stem geometries were implanted; the implant type B was used to compute an 'imperfection scenario'.
FINDINGS
Apparent bone density decreased by 4.3% in the entire femur with the implant type G, and by 12.3% with the implant type B. Bone mass loss was pronounced in the proximal calcar region. Apparent bone density increased at the lateral cortical ring and in the minor trochanter. The apparent bone density in the imperfection scenario was very similar to that of a straight stem, indicating a distal load transfer.
INTERPRETATION
No adverse effects of the A2 short-stemmed implant system on bone remodeling could be detected. The overall bone density reduction was acceptable, and wedge fixation was not observed, indicating that there was no distal load transfer. The simulation of an incongruous implant indicates the sensitivity of our model in response to modifications of implant positioning. Correct implant selection and positioning is crucial when using the A2 system.
Identifiants
pubmed: 30458330
pii: S0268-0033(18)30050-0
doi: 10.1016/j.clinbiomech.2018.11.002
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
31-37Informations de copyright
Copyright © 2018 Elsevier Ltd. All rights reserved.