Experimental and computational analysis of micromotions of an uncemented femoral knee implant using elastic and plastic bone material models

Sanaz Berahmani, Dennis Janssen, Nico Verdonschot

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

It is essential to calculate micromotions at the bone-implant interface of an uncemented femoral total knee replacement (TKR) using a reliable computational model. In the current study, experimental measurements of micromotions were compared with predicted micromotions by Finite Element Analysis (FEA) using two bone material models: linear elastic and post-yield material behavior, while an actual range of interference fit was simulated. The primary aim was to investigate whether a plasticity model is essential in order to calculate realistic micromotions. Additionally, experimental bone damage at the interface was compared with the FEA simulated range. TKR surgical cuts were applied to five cadaveric femora and micro- and clinical CT- scans of these un-implanted specimens were made to extract geometrical and material properties, respectively. Micromotions at the interface were measured using digital image correlation. Cadaver-specific FEA models were created based on the experimental set-up. The average experimental micromotion of all specimens was 53.1 ± 42.3 µm (mean ± standard deviation (SD)), which was significantly higher than the micromotions predicted by both models, using either the plastic or elastic material model (26.5 ± 23.9 µm and 10.1 ± 10.1 µm, respectively; p-value < 0.001 for both material models). The difference between the two material models was also significant (p-value < 0.001). The predicted damage had a magnitude and distribution which was comparable to the experimental bone damage. We conclude that, although the plastic model could not fully predict the micro motions, it is more suitable for pre-clinical assessment of a press-fit TKR implant than using an elastic bone model.

Original languageEnglish
Pages (from-to)137-143
Number of pages7
JournalJournal of biomechanics
Volume61
DOIs
Publication statusPublished - 16 Aug 2017

Fingerprint

Thigh
Knee Replacement Arthroplasties
Finite Element Analysis
Plastics
Knee
Bone
Bone and Bones
Knee prostheses
Cadaver
Femur
Linear Models
Finite element method
Computerized tomography
Interfaces (computer)
Plasticity
Materials properties

Keywords

  • Bone material model
  • Finite Element Analysis
  • Interference fit
  • Micromotion
  • Uncemented femoral total knee replacement

Cite this

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title = "Experimental and computational analysis of micromotions of an uncemented femoral knee implant using elastic and plastic bone material models",
abstract = "It is essential to calculate micromotions at the bone-implant interface of an uncemented femoral total knee replacement (TKR) using a reliable computational model. In the current study, experimental measurements of micromotions were compared with predicted micromotions by Finite Element Analysis (FEA) using two bone material models: linear elastic and post-yield material behavior, while an actual range of interference fit was simulated. The primary aim was to investigate whether a plasticity model is essential in order to calculate realistic micromotions. Additionally, experimental bone damage at the interface was compared with the FEA simulated range. TKR surgical cuts were applied to five cadaveric femora and micro- and clinical CT- scans of these un-implanted specimens were made to extract geometrical and material properties, respectively. Micromotions at the interface were measured using digital image correlation. Cadaver-specific FEA models were created based on the experimental set-up. The average experimental micromotion of all specimens was 53.1 ± 42.3 µm (mean ± standard deviation (SD)), which was significantly higher than the micromotions predicted by both models, using either the plastic or elastic material model (26.5 ± 23.9 µm and 10.1 ± 10.1 µm, respectively; p-value < 0.001 for both material models). The difference between the two material models was also significant (p-value < 0.001). The predicted damage had a magnitude and distribution which was comparable to the experimental bone damage. We conclude that, although the plastic model could not fully predict the micro motions, it is more suitable for pre-clinical assessment of a press-fit TKR implant than using an elastic bone model.",
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Experimental and computational analysis of micromotions of an uncemented femoral knee implant using elastic and plastic bone material models. / Berahmani, Sanaz; Janssen, Dennis; Verdonschot, Nico.

In: Journal of biomechanics, Vol. 61, 16.08.2017, p. 137-143.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - Janssen, Dennis

AU - Verdonschot, Nico

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