University of Oulu

Eve Salonius, Lassi Rieppo, Mikko J. Nissi, Hertta J. Pulkkinen, Harold Brommer, Anne Brünott, Tuomo S. Silvast, P. René Van Weeren, Virpi Muhonen, Pieter A. J. Brama & Ilkka Kiviranta (2019) Critical-sized cartilage defects in the equine carpus, Connective Tissue Research, 60:2, 95-106, DOI: 10.1080/03008207.2018.1455670

Critical-sized cartilage defects in the equine carpus

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Author: Salonius, Eve1; Rieppo, Lassi2,3; Nissi, Mikko J.4;
Organizations: 1Department of Orthopaedics and Traumatology, University of Helsinki, Helsinki, Finland
2Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
3Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
4Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
5Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
6Department of Equine Sciences, Utrecht University, Utrecht, The Netherlands
7SIB Labs, University of Eastern Finland, Kuopio, Finland
8Section of Veterinary Clinical Sciences, School of Veterinary Medicine, University College Dublin, Ireland
9Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
Persistent link:
Language: English
Published: Informa, 2019
Publish Date: 2019-04-12


Aim: The horse joint, due to its similarity with the human joint, is the ultimate model for translational articular cartilage repair studies. This study was designed to determine the critical size of cartilage defects in the equine carpus and serve as a benchmark for the evaluation of new cartilage treatment options.

Material and methods: Circular full-thickness cartilage defects with a diameter of 2, 4, and 8 mm were created in the left middle carpal joint and similar osteochondral (3.5 mm in depth) defects in the right middle carpal joint of 5 horses. Spontaneously formed repair tissue was examined macroscopically, with MR and µCT imaging, polarized light microscopy, standard histology, and immunohistochemistry at 12 months.

Results: Filling of 2 mm chondral defects was good (77.8 ± 8.5%), but proteoglycan depletion was evident in Safranin-O staining and gadolinium-enhanced MRI (T1Gd). Larger chondral defects showed poor filling (50.6 ± 2.7% in 4 mm and 31.9 ± 7.3% in 8 mm defects). Lesion filling in 2, 4, and 8 mm osteochondral defects was 82.3 ± 3.0%, 68.0 ± 4.6% and 70.8 ± 15.4%, respectively. Type II collagen staining was seen in 9/15 osteochondral defects but only in 1/15 chondral defects. Subchondral bone pathologies were evident in 14/15 osteochondral samples but only in 5/15 chondral samples. Although osteochondral lesions showed better neotissue quality than chondral lesions, the overall repair was deemed unsatisfactory because of the subchondral bone pathologies.

Conclusion: We recommend classifying 4 mm as critical osteochondral lesion size and 2 mm as critical chondral lesion size for cartilage repair research in the equine carpal joint model.

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Series: Connective tissue research
ISSN: 0300-8207
ISSN-E: 1607-8438
ISSN-L: 0300-8207
Volume: 60
Issue: 2
Pages: 95 - 106
DOI: 10.1080/03008207.2018.1455670
Type of Publication: A1 Journal article – refereed
Field of Science: 3111 Biomedicine
Funding: This study was funded by the Academy of Finland (Grant #285909) and the Finnish Funding Agency for Innovation Tekes (Grant 3344/31/03). The funding sources had no role in the study design, collection, analysis and interpretation of data; in the writing of the manuscript; and in the decision to submit the manuscript for publication.
Academy of Finland Grant Number: 285909
Detailed Information: 285909 (Academy of Finland Funding decision)
Copyright information: Copyright © 2018 Informa UK Limited. This is an Accepted Manuscript of an article published by Taylor & Francis in Connective Tissue Research on 12 Apr 2018, available online: