Subchondral bone failure in an equine model of overload arthrosis.
Abstract: Gross examination of metacarpo-/metatarsophalangeal (fetlock) joints from racehorses revealed defects on the condylar surface that ranged from cartilage fibrillation and erosion to focal cartilage indentations and cavitation in subchondral bone characteristic of traumatic osteochondrosis. Because these lesions represented a spectrum of mechanically induced arthrosis in which microdamage is thought to play a role, a histologic study of sagittal sections was made to study the morphogenesis. Subchondral bone failure developed beneath a flattened section of the condyle where the margin of the sesamoid bone produces compression as well as shear on impact of the foot with the ground. Milder lesions had thickening of subchondral bone and underlying trabeculae. With advancing sclerosis an increased amount of osteocyte necrosis was present. Occasional vascular channels with plugs of matrix debris and cells were present just beneath the cartilage. There was increased prominence of subchondral vessels, and osteoclastic remodeling was seen in and around the sclerotic zone. Apparent fragmentation lines in the subchondral bone suggested increased matrix fragility. Irregular trabecular microfractures developed at a depth of a few millimeters. Increased vascularity with hemorrhage, fibrin, and fibroplasia could be seen in enlarged marrow spaces at this more advanced stage. The overlying articular cartilage was variably indented but remained largely viable with degeneration and erosion limited to the superficial layers. Focally, breaks in the calcified layer appeared to lead to collapse and cartilage infolding. In metacarpal condyles from experimental horses run on a treadmill, there were milder changes at the site. The subchondral bone was increased in volume and there was increased diffuse staining with basic fuchsin, but no increase in the number of microcracks was seen. The findings in the racehorses indicate that the equine fetlock condyle is a consistent site of overload arthrosis in which microfracture and failure in subchondral bone may occur. Controlled exercise in treadmill horses may provide a model in which to study the pathogenesis.
Publication Date: 1998-02-26 PubMed ID: 9477236DOI: 10.1016/s8756-3282(97)00253-6Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research presents an investigation into the development of overload arthrosis, a joint condition, in racehorses. The study examines bone and cartilage defects at the joints and identifies potential causes, contributing to our broader understanding of arthrosis in equines.
Research Objective and Methodology
- The main objective of this study was to understand the morphogenesis or development process of overload arthrosis in racehorse joints, mainly focusing on the metacarpo-/metatarsophalangeal, also known as the fetlock joint. These joints were critically examined for defects ranging from cartilage fibrillation and erosion to cavitation in the subchondral bone, which is indicative of traumatic osteochondrosis.
- The researchers conducted a histologic analysis of sagittal sections to help understand the condition’s progression. They also explored an experimental model using horses run on a treadmill, to study milder changes at the site.
Findings
- Defects were discovered in the subchondral bone developed beneath a section of the condyle where the sesamoid bone and the ground’s impact cause compression and shear. Enhanced osteocyte necrosis was found in more severe lesions accompanied by thickened subchondral bone and the underlying trabeculae.
- The researchers observed the increased prominence of subchondral vessels and osteoclastic remodeling in the sclerotic zone. They also found increased matrix fragility, indicative of microfractures, in the trabeculae a few millimeters beneath the bone surface.
- The study identifies a series of later-stage indicators, including increased vascularity along with hemorrhage, fibrin, and fibroplasia in enlarged marrow spaces. The researchers also noted degradation in the overlying articular cartilage, particularly in the superficial layers.
- In horses that were run on a treadmill for the experiment, milder changes were noticed. The subchondral bone volume was slightly increased and there was increased staining with basic fuchsin, but an increase in microcracks was not observed.
Implications
- The defects observed in the racehorses prompted the suggestion that the equine fetlock condyle may be a consistent site vulnerable to overload arthrosis. Microfracture and failure in subchondral bone seem common, potentially leading to this condition.
- The study alludes to control exercised in treadmill horses as a possible model for further understanding overload arthrosis pathogenesis.
This research study provides vital insights into the development and manifestation of overload arthrosis in racehorses, enhancing our understanding of equine joint health and potentially informing improved preventative measures and therapeutic approaches.
Cite This Article
APA
Norrdin RW, Kawcak CE, Capwell BA, McIlwraith CW.
(1998).
Subchondral bone failure in an equine model of overload arthrosis.
Bone, 22(2), 133-139.
https://doi.org/10.1016/s8756-3282(97)00253-6 Publication
Researcher Affiliations
- Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
MeSH Terms
- Animals
- Biomechanical Phenomena
- Bone Matrix / pathology
- Calcinosis / physiopathology
- Cartilage, Articular / pathology
- Disease Models, Animal
- Exercise Test
- Fractures, Bone / physiopathology
- Horse Diseases / etiology
- Horse Diseases / physiopathology
- Horses
- Metacarpophalangeal Joint / blood supply
- Metacarpophalangeal Joint / injuries
- Metacarpus / pathology
- Metatarsophalangeal Joint / blood supply
- Metatarsophalangeal Joint / injuries
- Necrosis
- Osteoarthritis / veterinary
- Osteocytes / pathology
- Physical Conditioning, Animal
Citations
This article has been cited 16 times.- Xilin C, Yan G, Juan LU, Luxue Q, Tingyao HU, Xin Z, Xinyue W, Anran Z, Yuxin Z, Honggang Z, Changqing G. Acupotomy ameliorates subchondral bone absorption and mechanical properties in rabbits with knee osteoarthritis by regulating bone morphogenetic protein 2-Smad1 pathway.. J Tradit Chin Med 2023 Aug;43(4):734-743.
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