Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures.
Abstract: To determine changes in the distal ends of the third metacarpal and metatarsal bones (MCIII and MTIII) of Thoroughbred racehorses that had sustained a catastrophic condylar fracture during high-speed exercise. Methods: Fractured and contralateral MCIIIs and MTIIIs from 11 Thoroughbred racehorses that sustained a displaced condylar fracture during racing, both MCIIIs from 5 Thoroughbred racehorses euthanatized because of a catastrophic injury other than a condylar fracture, and both MCIIIs from 5 horses of other breeds that had not been professionally trained or raced. Methods: Macroscopic observations were made of the distal ends of the bones before and after digestion of the articular cartilage with NaOH. Results: In all 11 racehorses with a displaced condylar fracture, the fracture was associated with a branching array of cracks in the condylar groove. In this region, fracture margins were smooth, and there was loss of subchondral bone. Comminution of the dorsal cortex was also seen. Parasagittal linear wear lines in the articular cartilage, erosions in the articular cartilage of the condyles, loss of the underlying subchondral bone, and cracking of condylar grooves were all more severe in the Thoroughbred racehorses than in the horses that had not been professionally trained or raced. Conclusions: Results suggest that condylar fractures in horses are pathologic fatigue or stress fractures that arise from a preexisting, branching array of cracks in the condylar groove of the distal end of MCIII or MTIII.
Publication Date: 2003-09-19 PubMed ID: 13677388DOI: 10.2460/ajvr.2003.64.1110Google 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
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This study investigates the changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses that have suffered a major condylar fracture during high-speed exercise. The evidence suggests that condylar fractures in horses are fatigue or stress fractures that arise from pre-existing cracks in specific areas of these bones.
Study Design and Methodology
- The bones under study were from 11 Thoroughbred racehorses had sustained a condylar fracture during racing. These included fractured and non-fractured metacarpal and metatarsal bones.
- The control group consisted of comparable bones from 5 Thoroughbred horses that were euthanized due to catastrophic injuries unrelated to a condylar fracture. Additional bones were obtained from 5 horses belonging to different breeds that had not undergone professional race training.
- Observations
were made of the distal ends of these bones at both before and after a digestion process of the articular cartilage using sodium hydroxide (NaOH).
Findings and Observations
- In all the observed racehorses with a condylar fracture, the break was associated with the development of a spreading pattern of cracks located in the condylar groove.
- Within the fracture region, the margins were smooth, and there was a notable loss of subchondral bone, which lies underneath the joint cartilage.
- There were signs of fragmentation (comminution) on the dorsal cortex of the bone.
- Linear wear lines in the articular cartilage, erosion of the cartilage on the condyles, loss of the underlying subchondral bone and cracking of the condylar grooves were all more severe in the racehorses than in the untrained horses.
Conclusions
- The study results suggest that condylar fractures in Thoroughbred racehorses are likely the result of stress or fatigue fractures. These fractures apparently stem from a pre-existing set of cracks which form a branching array located in the condylar groove at the distal end of the third metacarpal or metatarsal bones.
- The findings emphasize the role of excessive physical stress in the development of these fractures, particularly due to high-speed equine racing. It also highlights the potential significance of early detection methods to mitigate the severity of such injuries.
Cite This Article
APA
Radtke CL, Danova NA, Scollay MC, Santschi EM, Markel MD, Da Costa Gómez T, Muir P.
(2003).
Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures.
Am J Vet Res, 64(9), 1110-1116.
https://doi.org/10.2460/ajvr.2003.64.1110 Publication
Researcher Affiliations
- Comparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA.
MeSH Terms
- Animals
- Cartilage, Articular / pathology
- Forelimb / pathology
- Fractures, Bone / pathology
- Fractures, Bone / veterinary
- Horse Diseases / pathology
- Horses
- Male
- Metacarpal Bones / pathology
- Metatarsal Bones / pathology
- Physical Conditioning, Animal / adverse effects
Citations
This article has been cited 16 times.- Johnston GCA, Ahern BJ, Palmieri C, Young AC. Imaging and Gross Pathological Appearance of Changes in the Parasagittal Grooves of Thoroughbred Racehorses. Animals (Basel) 2021 Nov 24;11(12).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Bishop EL, Woldeyohannes SM, Perkins NR, Ahern BJ. A Prospective Study of Training Methods for Two-Year-Old Thoroughbred Racehorses in Queensland, Australia, and Analysis of the Differences in Training Methods between Trainers of Varying Stable Sizes. Animals (Basel) 2021 Mar 25;11(4).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses. Animals (Basel) 2020 Nov 5;10(11).
- Spargo KE, Rubio-Martinez LM, Wheeler DP, Fletcher L, Carstens A. Catastrophic musculoskeletal injuries in Thoroughbred racehorses on racetracks in Gauteng, South Africa. J S Afr Vet Assoc 2019 Feb 28;90(0):e1-e5.
- Liley H, Zhang J, Firth EC, Fernandez JW, Besier TF. Statistical modeling of the equine third metacarpal bone incorporating morphology and bone mineral density. PLoS One 2018;13(6):e0194406.
- Martig S, Hitchens PL, Stevenson MA, Whitton RC. Subchondral bone morphology in the metacarpus of racehorses in training changes with distance from the articular surface but not with age. J Anat 2018 Jun;232(6):919-930.
- Hopper N, Singer E, Henson F. Increased sclerostin associated with stress fracture of the third metacarpal bone in the Thoroughbred racehorse. Bone Joint Res 2018 Jan;7(1):94-102.
- Shu Y, Baumann MJ, Case ED, Irwin RK, Meyer SE, Pearson CS, McCabe LR. Surface microcracks signal osteoblasts to regulate alignment and bone formation. Mater Sci Eng C Mater Biol Appl 2014 Nov;44:191-200.
- Dubois MS, Morello S, Rayment K, Markel MD, Vanderby R Jr, Kalscheur VL, Hao Z, McCabe RP, Marquis P, Muir P. Computed tomographic imaging of subchondral fatigue cracks in the distal end of the third metacarpal bone in the thoroughbred racehorse can predict crack micromotion in an ex-vivo model. PLoS One 2014;9(7):e101230.
- Turley SM, Thambyah A, Riggs CM, Firth EC, Broom ND. Microstructural changes in cartilage and bone related to repetitive overloading in an equine athlete model. J Anat 2014 Jun;224(6):647-58.
- Muir P, Peterson AL, Sample SJ, Scollay MC, Markel MD, Kalscheur VL. Exercise-induced metacarpophalangeal joint adaptation in the Thoroughbred racehorse. J Anat 2008 Dec;213(6):706-17.
- Firth EC. The response of bone, articular cartilage and tendon to exercise in the horse. J Anat 2006 Apr;208(4):513-26.
- Irandoust S, Whitton C, Henak C, Muir P. Tuning and validation of a virtual mechanical testing pipeline for condylar stress fracture risk assessment in Thoroughbred racehorses. R Soc Open Sci 2025 May;12(5):241935.
- Irandoust S, O'Neil LM, Stevenson CM, Franseen FM, Ramzan PHL, Powell SE, Brounts SH, Loeber SJ, Ergun DL, Whitton RC, Henak CR, Muir P. Comparison of radiography and computed tomography for identification of third metacarpal structural change and associated assessment of condylar stress fracture risk in Thoroughbred racehorses. Equine Vet J 2025 May;57(3):723-736.
- Lin ST, Foote AK, Bolas NM, Sargan DR, Murray RC. Histological and Histopathological Features of the Third Metacarpal/Tarsal Parasagittal Groove and Proximal Phalanx Sagittal Groove in Thoroughbred Horses with Racing History. Animals (Basel) 2024 Jun 30;14(13).
- Bergstrom TC, Spriet M, Carpenter RS, Jacques KL, Stover SM. Condylar fracture location is correlated to exercise history in Thoroughbred racehorses. Equine Vet J 2025 Jan;57(1):76-86.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
