University of Oulu

Das Gupta, S., Workman, J., Finnilä, M. A. J., Saarakkala, S., & Thambyah, A. (2022). Subchondral bone plate thickness is associated with micromechanical and microstructural changes in the bovine patella osteochondral junction with different levels of cartilage degeneration. Journal of the Mechanical Behavior of Biomedical Materials, 129, 105158. https://doi.org/10.1016/j.jmbbm.2022.105158

Subchondral bone plate thickness is associated with micromechanical and microstructural changes in the bovine patella osteochondral junction with different levels of cartilage degeneration

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Author: Das Gupta, Shuvashis1; Workman, Joshua2; Finnilä, Mikko A.J.1;
Organizations: 1Research Unit of Medical Imaging, Physics, and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
2Department of Chemical and Materials Engineering, The University of Auckland, Auckland, New Zealand
3Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 13.3 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2022051034174
Language: English
Published: Elsevier, 2022
Publish Date: 2022-06-21
Description:

Abstract

The influence of joint degeneration on the biomechanical properties of calcified cartilage and subchondral bone plate at the osteochondral junction is relatively unknown. Common experimental difficulties include accessibility to and visualization of the osteochondral junction, application of mechanical testing at the appropriate length scale, and availability of tissue that provides a consistent range of degenerative changes. This study addresses these challenges.

A well-established bovine patella model of early joint degeneration was employed, in which micromechanical testing of fully hydrated osteochondral sections was carried out in conjunction with high-resolution imaging using differential interference contrast (DIC) optical light microscopy. A total of forty-two bovine patellae with different grades of tissue health ranging from healthy to mild, moderate, and severe cartilage degeneration, were selected. From the distal–lateral region of each patella, two adjacent osteochondral sections were obtained for the mechanical testing and the DIC imaging, respectively. Mechanical testing was carried out using a robotic micro-force acquisition system, applying compression tests over an array (area: 200 μm × 1000 μm, step size: 50 μm) across the osteochondral junction to obtain a stiffness map. Morphometric analysis was performed for the DIC images of fully hydrated cryo-sections. The levels of cartilage degeneration, DIC images, and the stiffness maps were used to associate the mechanical properties onto the specific tissue regions of cartilage, calcified cartilage, and subchondral bone plate.

The results showed that there were up to 20% and 24% decreases (p < 0.05) in the stiffness of calcified cartilage and subchondral bone plate, respectively, in the severely degenerated group compared to the healthy group. Furthermore, there were increases (p < 0.05) in the number of tidemarks, bone spicules at the cement line, and the mean thickness of the subchondral bone plate with increasing levels of degeneration.

The decreasing stiffness in the subchondral bone plate coupled with the presence of bone spicules may be indicative of a subchondral remodeling process involving new bone formation. Moreover, the mean thickness of the subchondral bone plate was found to be the strongest indicator of mechanical and associated structural changes in the osteochondral joint tissues.

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Series: Journal of the mechanical behavior of biomedical materials
ISSN: 1751-6161
ISSN-E: 1878-0180
ISSN-L: 1751-6161
Volume: 129
Article number: 105158
DOI: 10.1016/j.jmbbm.2022.105158
OADOI: https://oadoi.org/10.1016/j.jmbbm.2022.105158
Type of Publication: A1 Journal article – refereed
Field of Science: 217 Medical engineering
Subjects:
Funding: This work was supported by funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 713645. Author S.S. acknowledges grants from Academy of Finland (Grants No. 268378, and 303786) and grants from European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013; ERC Grant Agreement No. 336267), during the conduct of the study.
EU Grant Number: (713645) BioMEP - Biomedical Engineering and Medical Physics
Academy of Finland Grant Number: 268378
303786
Detailed Information: 268378 (Academy of Finland Funding decision)
303786 (Academy of Finland Funding decision)
Copyright information: © 2022 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
  https://creativecommons.org/licenses/by/4.0/