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Doctoral thesis, 2014

Imaging of early distal tarsal osteoarthritis in Icelandic horses

Ley, Charles


The early stages of osteoarthritis (OA) are characterised by focal morphological changes that may slowly progress if joint repair fails. Validated, non-invasive and affordable methods to diagnose the early stage of OA in horses are lacking. The objectives of this thesis were to investigate and validate OA detection methods, and describe the morphological OA changes in the distal tarsal region of a group of young Icelandic horses. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI), light microscopy histology, backscattered electron scanning electron microscopy, and confocal scanning light microscopy were used to investigate osteochondral changes in the joints of the distal tarsal region in 38 two-and-a-half year old Icelandic horses. Radiographs were taken of live horses standing, all other examinations were performed 2-3 months later on non-weight bearing cadaver specimens from the same horses. The results showed that a novel CT and MRI guidance method for osteochondral tissue sample collection improved detection of early OA changes in centrodistal (distal intertarsal) joints compared to standardised sample collection from predetermined locations. Diagnostic imaging and microscopy showed that early OA morphological changes primarily occur in the articular hyaline and calcified cartilage rather than the subchondral bone. The lesions articular mineralisation front defect, central osteophytes and hyperdense mineralisation front protrusions were described in detail in the joints of the distal tarsal region using combined microscopic imaging of embedded block specimens. A comparison of clinical diagnostic imaging methods found that radiography was equal or better than low-field MRI for the detection of early OA in centrodistal joints. Articular mineralisation front defects were identified as a highly specific imaging feature in radiographs for early OA. This thesis provides a detailed morphological description of the osteochondral changes occurring in the early stages of OA in the centrodistal joint of Icelandic horses and proposes a validated, non-invasive, cost-effective radiography method for proceeding with future longitudinal studies of early OA in Icelandic horses.


magnetic resonance imaging; computed tomography; radiology; radiography; equine; bone spavin; osteoarthrosis; degenerative joint disease; articular cartilage; microscopy

Published in

Acta Universitatis Agriculturae Sueciae
2014, number: 2014:53
ISBN: 978-91-576-8054-9, eISBN: 978-91-576-8055-6
Publisher: Department of Clinical Sciences, Swedish University of Agricultural Sciences

Authors' information

Swedish University of Agricultural Sciences, Department of Clinical Sciences

UKÄ Subject classification

Clinical Science

URI (permanent link to this page)