Relationship between cartilage and subchondral bone lesions in repetitive impact trauma-induced equine osteoarthritis

Comparative Orthopaedic Research Laboratory, Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, Saint-Hyacinthe (QC), J2S 7C6, Canada.
Osteoarthritis and Cartilage (Impact Factor: 4.17). 02/2012; 20(6):572-83. DOI: 10.1016/j.joca.2012.02.004
Source: PubMed


To correlate degenerative changes in cartilage and subchondral bone in the third carpal bone (C3) of Standardbred racehorses with naturally occurring repetitive trauma-induced osteoarthritis.
Fifteen C3, collected from Standardbred horses postmortem, were assessed for cartilage lesions by visual inspection and divided into Control (CO), Early Osteoarthritis (EOA) and Advanced Osteoarthritis (AOA) groups. Two osteochondral cores were harvested from corresponding dorsal sites on each bone and scanned with a micro-computed tomography (CT) instrument. 2D images were assembled into 3D reconstructions that were used to quantify architectural parameters from selected regions of interest, including bone mineral density and bone volume fraction. 2D images, illustrating the most severe lesion per core, were scored for architectural appearance by blinded observers. Thin sections of paraffin-embedded decalcified cores stained with Safranin O-Fast Green, matched to the micro-CT images, were scored using a modified Mankin scoring system.
Subchondral bone pits with deep focal areas of porosity were seen more frequently in AOA than EOA but never in CO. Articular cartilage damage was seen in association with a reduction in bone mineral and loss of bone tissue. Histological analyses revealed significant numbers of microcracks in the calcified cartilage of EOA and AOA groups and a progressive increase in the score compared with CO bones.
The data reveal corresponding, progressive degenerative changes in articular cartilage and subchondral bone, including striking focal resorptive lesions, in the third carpal bone of racehorses subjected to repetitive, high impact trauma.

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Available from: Guy Beauchamp, Oct 14, 2015
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    • "In a series of in vitro studies of bovine cartilage, Broom and his colleagues have shown that the mode of fracture of HAC and ACC under high loading rates is influenced by previous static creep loading (Thambyah et al. 2012). Lacourt et al. (2012) used both microtomography and decalcified section to quantify cracks in the equine third carpal bone as a natural model of repetitive injuryinduced arthritis. X-ray microtomography was introduced to the bone field by Elliott & Dover (1982, 1984). "
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    ABSTRACT: High density mineralised protrusions (HDMP) from the tidemark mineralising front into hyaline articular cartilage (HAC) were first described in Thoroughbred racehorse fetlock joints and later in Icelandic horse hock joints. We now report them in human material. Whole femoral heads removed at operation for joint replacement or from dissection room cadavers were imaged using magnetic resonance imaging (MRI) dual echo steady state at 0.23 mm resolution, then 26-μm resolution high contrast X-ray microtomography, sectioned and embedded in polymethylmethacrylate, blocks cut and polished and re-imaged with 6-μm resolution X-ray microtomography. Tissue mineralisation density was imaged using backscattered electron SEM (BSE SEM) at 20 kV with uncoated samples. HAC histology was studied by BSE SEM after staining block faces with ammonium triiodide solution. HDMP arise via the extrusion of an unknown mineralisable matrix into clefts in HAC, a process of acellular dystrophic calcification. Their formation may be an extension of a crack self-healing mechanism found in bone and articular calcified cartilage. Mineral concentration exceeds that of articular calcified cartilage and is not uniform. It is probable that they have not been reported previously because they are removed by decalcification with standard protocols. Mineral phase morphology frequently shows the agglomeration of many fine particles into larger concretions. HDMP are surrounded by HAC, are brittle, and show fault lines within them. Dense fragments found within damaged HAC could make a significant contribution to joint destruction. At least larger HDMP can be detected with the best MRI imaging ex vivo.
    Journal of Anatomy 10/2014; 225(4):n/a-n/a. DOI:10.1111/joa.12226 · 2.10 Impact Factor
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    • "It is economically important throughout the world and has been used for transportation and entertainment. Moreover, horse is a medically valuable animal model because the species shares over 90 hereditary conditions with human disorders [27]–[28] as well as many medical conditions such as allergies and osteoarthritis [29]–[30]. Furthermore, horse can be a valuable model organism for studying biomechanics and exercise physiology [31]. The present study was performed to characterize miRNAs in normal horse tissues by using Illumina high-throughput NGS technology. "
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    • "Such loading would, at some point, be likely to produce tendon inflammation, microtears or disruption [29,30,48], bone microscopic damage (e.g. increased resorption spaces and microcracks, which are small linear or elliptical cracks between osteons [23,28,112]); cartilage tidemark changes, microcracks and subchondral resorptive lesions [49,120,141]; or diffuse tissue damage when tissues are exposed to additional high force loading cycles. The theory of fatigue loading as a mechanism of tissue injury is supported in biomaterials testing of cadaveric materials, such as spine motion segments [142] and tendons [48,50,51,143]. "
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