University of Oulu

Aho O-M, Finnilä M, Thevenot J, Saarakkala S, Lehenkari P (2017) Subchondral bone histology and grading in osteoarthritis. PLoS ONE 12(3): e0173726.

Subchondral bone histology and grading in osteoarthritis

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Author: Aho, Olli-Matti1; Finnilä, Mikko2; Thevenot, Jerome2;
Organizations: 1Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu, Finland
2Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
3Department of Diagnostic Radiology, Medical Research Center, Oulu University Hospital, Oulu, Finland
4Division of Orthopaedic and Trauma Surgery, Department of Surgery, Medical Research Center, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
Persistent link:
Language: English
Published: Public Library of Science, 2017
Publish Date: 2017-07-07


Objective: Osteoarthritis (OA) has often regarded as a disease of articular cartilage only. New evidence has shifted the paradigm towards a system biology approach, where also the surrounding tissue, especially bone is studied more vigorously. However, the histological features of subchondral bone are only poorly characterized in current histological grading scales of OA. The aim of this study is to specifically characterize histological changes occurring in subchondral bone at different stages of OA and propose a simple grading system for them.

Design: 20 patients undergoing total knee replacement surgery were randomly selected for the study and series of osteochondral samples were harvested from the tibial plateaus for histological analysis. Cartilage degeneration was assessed using the standardized OARSI grading system, while a novel four-stage grading system was developed to illustrate the changes in subchondral bone. Subchondral bone histology was further quantitatively analyzed by measuring the thickness of uncalcified and calcified cartilage as well as subchondral bone plate. Furthermore, internal structure of calcified cartilage-bone interface was characterized utilizing local binary patterns (LBP) based method.

Results: The histological appearance of subchondral bone changed drastically in correlation with the OARSI grading of cartilage degeneration. As the cartilage layer thickness decreases the subchondral plate thickness and disorientation, as measured with LBP, increases. Calcified cartilage thickness was highest in samples with moderate OA.

Conclusion: The proposed grading system for subchondral bone has significant relationship with the corresponding OARSI grading for cartilage. Our results suggest that subchondral bone remodeling is a fundamental factor already in early stages of cartilage degeneration.

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Series: PLoS one
ISSN: 1932-6203
ISSN-E: 1932-6203
ISSN-L: 1932-6203
Volume: 12
Issue: 3
Article number: e0173726
DOI: 10.1371/journal.pone.0173726
Type of Publication: A1 Journal article – refereed
Field of Science: 217 Medical engineering
Funding: This study was financially supported by the Academy of Finland (project 127198), and strategic funding of the University of Oulu (project 24001200).
Dataset Reference: Supporting information
Copyright information: © 2017 Aho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.