Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Degeneration dependent changes in human knee cartilage mechanical properties revealed by synchrotron tomography based finite element modeling

Jönsson, Viktor LU ; Grassi, Lorenzo LU orcid ; Gustafsson, Anna LU orcid ; Pierantoni, Maria LU orcid ; Dejea, Hector LU ; Sjögren, Amanda LU orcid ; Schlepütz, Christian M. ; Englund, Martin LU orcid and Isaksson, Hanna LU orcid (2026) In Osteoarthritis and Cartilage Open 8(3).
Abstract

Objective: Knee osteoarthritis (OA) is a chronic joint disease associated with pain and reduced function. The mechanisms underlying OA and how mechanical properties change with the disease are not fully understood, partly due to large variability during mechanical testing of cartilage. We characterized the mechanical properties of human femoral cartilage with varying levels of degeneration using a tissue constitution specific fibril-reinforced poroelastic (FRPE) material model. Method: We created sample-specific finite element (FE) models based on synchrotron-based x-ray tomography to reduce the variability caused by sample geometry. For comparison, idealized FE models were also created without tomography data. Cartilage samples (n =... (More)

Objective: Knee osteoarthritis (OA) is a chronic joint disease associated with pain and reduced function. The mechanisms underlying OA and how mechanical properties change with the disease are not fully understood, partly due to large variability during mechanical testing of cartilage. We characterized the mechanical properties of human femoral cartilage with varying levels of degeneration using a tissue constitution specific fibril-reinforced poroelastic (FRPE) material model. Method: We created sample-specific finite element (FE) models based on synchrotron-based x-ray tomography to reduce the variability caused by sample geometry. For comparison, idealized FE models were also created without tomography data. Cartilage samples (n = 15) were mechanically tested in compressive stress relaxation (two steps of 15% strain) with in-situ x-ray tomography. Adjacent tissue samples were histopathologically graded (OARSI). The FRPE parameters were optimized to minimize differences between experimental and simulated stress relaxation forces. Identified material parameters were analyzed with linear regression, with OARSI grade as independent variable. Results: We identified reductions in both collagen (-2x) and non-fibrillar matrix stiffness (-3x) accompanied by increased permeability (+5.5x) when comparing tissue with OARSI grade 1 and 5 in tomography-based FE models. At OARSI = 1, in idealized and tomography-based models, the collagen stiffness, non-fibrillar matrix stiffness and permeability differed 20, 110 and 55% respectively. Only collagen and non-fibrillar matrix stiffness were associated with OARSI grade in idealized models. Conclusion: Segmentation-based models were better at detecting degeneration-related mechanical changes than idealized models. The identified parameter changes match known OA tissue developments and can be used in predictive FE knee joint models.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Articular cartilage, Fibril-reinforced poroelastic, OARSI grade, Osteoarthritis, Stress-relaxation
in
Osteoarthritis and Cartilage Open
volume
8
issue
3
article number
100825
publisher
Elsevier
external identifiers
  • scopus:105041250427
  • pmid:42290682
ISSN
2665-9131
DOI
10.1016/j.ocarto.2026.100825
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2026 The Author(s)
id
89100e93-ce5e-4407-b09e-072eb4025a76
date added to LUP
2026-06-17 08:37:20
date last changed
2026-08-27 20:35:07
@article{89100e93-ce5e-4407-b09e-072eb4025a76,
  abstract     = {{<p>Objective: Knee osteoarthritis (OA) is a chronic joint disease associated with pain and reduced function. The mechanisms underlying OA and how mechanical properties change with the disease are not fully understood, partly due to large variability during mechanical testing of cartilage. We characterized the mechanical properties of human femoral cartilage with varying levels of degeneration using a tissue constitution specific fibril-reinforced poroelastic (FRPE) material model. Method: We created sample-specific finite element (FE) models based on synchrotron-based x-ray tomography to reduce the variability caused by sample geometry. For comparison, idealized FE models were also created without tomography data. Cartilage samples (n = 15) were mechanically tested in compressive stress relaxation (two steps of 15% strain) with in-situ x-ray tomography. Adjacent tissue samples were histopathologically graded (OARSI). The FRPE parameters were optimized to minimize differences between experimental and simulated stress relaxation forces. Identified material parameters were analyzed with linear regression, with OARSI grade as independent variable. Results: We identified reductions in both collagen (-2x) and non-fibrillar matrix stiffness (-3x) accompanied by increased permeability (+5.5x) when comparing tissue with OARSI grade 1 and 5 in tomography-based FE models. At OARSI = 1, in idealized and tomography-based models, the collagen stiffness, non-fibrillar matrix stiffness and permeability differed 20, 110 and 55% respectively. Only collagen and non-fibrillar matrix stiffness were associated with OARSI grade in idealized models. Conclusion: Segmentation-based models were better at detecting degeneration-related mechanical changes than idealized models. The identified parameter changes match known OA tissue developments and can be used in predictive FE knee joint models.</p>}},
  author       = {{Jönsson, Viktor and Grassi, Lorenzo and Gustafsson, Anna and Pierantoni, Maria and Dejea, Hector and Sjögren, Amanda and Schlepütz, Christian M. and Englund, Martin and Isaksson, Hanna}},
  issn         = {{2665-9131}},
  keywords     = {{Articular cartilage; Fibril-reinforced poroelastic; OARSI grade; Osteoarthritis; Stress-relaxation}},
  language     = {{eng}},
  number       = {{3}},
  publisher    = {{Elsevier}},
  series       = {{Osteoarthritis and Cartilage Open}},
  title        = {{Degeneration dependent changes in human knee cartilage mechanical properties revealed by synchrotron tomography based finite element modeling}},
  url          = {{http://dx.doi.org/10.1016/j.ocarto.2026.100825}},
  doi          = {{10.1016/j.ocarto.2026.100825}},
  volume       = {{8}},
  year         = {{2026}},
}