• 1

    Norrdin RWKawcak CECapwell BA, et al. Subchondral bone failure in an equine model of overload arthrosis. Bone 1998;22:133139.

  • 2

    Riggs CMWhitehouse GHBoyde A. Structural variation of the distal condyles of the third metacarpal and third metatarsal bones in the horse. Equine Vet J 1999;31:130139.

    • Search Google Scholar
    • Export Citation
  • 3

    Riggs CMWhitehouse GHBoyde A. Pathology of the distal condyles of the third metacarpal and third metatarsal bones of the horse. Equine Vet J 1999;31:140148.

    • Search Google Scholar
    • Export Citation
  • 4

    Riggs CMBoyde A. Effect of exercise on bone density in distal regions of the equine third metacarpal bone in 2-year-old Thoroughbreds. Equine Vet J Suppl 1999;(30):555560.

    • Search Google Scholar
    • Export Citation
  • 5

    Kawcak CEMcIlwraith CWNorrdin RW, et al. Clinical effects of exercise on subchondral bone of carpal and metacarpophalangeal joints in horses. Am J Vet Res 2000;61:12521258.

    • Search Google Scholar
    • Export Citation
  • 6

    Rubio-Martinez LMCruz AMGordon K, et al. Structural characterization of the distal aspect of third metacarpal subchondral bones in Thoroughbred racehorses by micro-computed tomography. Am J Vet Res 2008;69:14131422.

    • Search Google Scholar
    • Export Citation
  • 7

    Rubio-Martinez LMCruz AMGordon K, et al. Mechanical properties of subchondral bone in the distal aspect of third metacarpal bones from Thoroughbred racehorses. Am J Vet Res 2008;69:14231433.

    • Search Google Scholar
    • Export Citation
  • 8

    Stepnik MWRadtke CLScollay MC, et al. Scanning electron microscopic examination of third metacarpal/third metatarsal bone failure surfaces in thoroughbred racehorses with condylar fracture. Vet Surg 2004;33:210.

    • Search Google Scholar
    • Export Citation
  • 9

    Radtke CLDanova NAScollay MC, et al. Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures. Am J Vet Res 2003;64:11101116.

    • Search Google Scholar
    • Export Citation
  • 10

    Wolff J. Ueber die innere Architektur der Knochen und ihre Bedeuting fuer die Frage von Knochenwachstum. Virchows Archiv Pathol Anat Physiol 1870;50:389453.

    • Search Google Scholar
    • Export Citation
  • 11

    Lanyon LE. Experimental support for the trajectorial theory of bone structure. J Bone Joint Surg Br 1974;56:160166.

  • 12

    Lanyon LE. Functional strain in bone tissue as an objective, and controlling stimulus for adaptive bone remodelling. J Biomech 1987;20:10831093.

    • Search Google Scholar
    • Export Citation
  • 13

    Turner CH. On Wolff's law of trabecular architecture. J Biomech 1992;25:19.

  • 14

    Riggs CMVaughan LCEvans GP, et al. Mechanical implications of collagen fibre orientation in cortical bone of the equine radius. Anat Embryol (Berl) 1993;187:239248.

    • Search Google Scholar
    • Export Citation
  • 15

    Thomason JJ. The relationship of structure to mechanical function in the third metacarpal bone of the horse, Equus caballus. Can J Zool 1985;63:14201428.

    • Search Google Scholar
    • Export Citation
  • 16

    Boyde AHaroon YJones SJ, et al. Three dimensional structure of the distal condyles of the third metacarpal bone of the horse. Equine Vet J 1999;31:122129.

    • Search Google Scholar
    • Export Citation
  • 17

    Yoshihara TKaneko MOikawa M, et al. An application of the image analyzer to the soft radiogram of the third metacarpus in horses. Jpn J Vet Sci 1989;51:184186.

    • Search Google Scholar
    • Export Citation
  • 18

    Whitehouse WJ. The quantitative morphology of anisotropic trabecular bone. J Microsc 1974;101:153168.

  • 19

    Harrigan TBMann RW. Characterization of microstructural anisotropy in orthotropic materials using a second rank tensor. J Mater Sci 1984;19:761767.

    • Search Google Scholar
    • Export Citation
  • 20

    Odgaard A. Three-dimensional methods for quantification of cancellous bone architecture. Bone 1997;20:315328.

  • 21

    Wachsmuth LEngelke K. High-resolution imaging of osteoarthritis using microcomputed tomography. Methods Mol Med 2004;101:231248.

  • 22

    Cruz AMHurtig MBGoldie K, et al. Staging an. progression of subchondral bone disease in the fetlock of the equine athlete, in Proceedings. 15th Annu Sci Meet Eur Coll Vet Surg 2006;132133.

    • Search Google Scholar
    • Export Citation
  • 23

    Easton KLKawcak CE. Evaluation of increased subchondral bone density in areas of contact in the metacarpophalangeal joint during joint loading in horses. Am J Vet Res 2007;68:816821.

    • Search Google Scholar
    • Export Citation
  • 24

    Norrdin RWStover SM. Subchondral bone failure in overload arthrosis: a scanning electron microscopic study in horses. J Musculoskelet Neuronal Interact 2006;6:251257.

    • Search Google Scholar
    • Export Citation
  • 25

    Davison KSSiminoski KAdachi JD, et al. Bone strength: the whole is greater than the sum of its parts. Semin Arthritis Rheum 2006;36:2231.

    • Search Google Scholar
    • Export Citation
  • 26

    Norrdin RWBay BKDrews MJ, et al. Overload arthrosis: strain patterns in the equine metacarpal condyle. J Musculoskelet Neuronal Interact 2001;1:357362.

    • Search Google Scholar
    • Export Citation
  • 27

    Young BDSamii VFMattoon JS, et al. Subchondral bone density and cartilage degeneration patterns in osteoarthritic metacarpal condyles of horses. Am J Vet Res 2007;68:841849.

    • Search Google Scholar
    • Export Citation
  • 28

    Fischer KJJacobs CRCarter DR. Computational method for determination of bone and joint loads using bone density distributions. J Biomech 1995;28:11271135.

    • Search Google Scholar
    • Export Citation

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Analysis of the subchondral microarchitecture of the distopalmar aspect of the third metacarpal bone in racing Thoroughbreds

Luis M. Rubio-Martínez DVM, PhD, DVSc1, Antonio M. Cruz DVM, MVM, MSc, DrMedVet2, Dean Inglis PhD3, and Mark B. Hurtig DVM, MVSc4
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  • 1 Comparative Orthopedics Research Laboratory, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
  • | 2 Comparative Orthopedics Research Laboratory, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
  • | 3 Department of Civil Engineering, Faculty of Engineering, McMaster University Hamilton, ON L8S 4L8, Canada.
  • | 4 Comparative Orthopedics Research Laboratory, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.

Abstract

Objective—To determine the anisotropic characteristics of the microarchitecture of the subchondral bone (SCB) plate and trabecular bone (TBB) of the distopalmar aspect of the metacarpal condyles in horses with different stages of SCB disease.

Sample Population—12 third metacarpal bone pairs from racing Thoroughbreds euthanized for diverse reasons.

Procedures—Both metacarpi were collected from horses with SCB changes that were mild (sclerosis and focal radiolucencies; n = 6) or severe (multifocal radiolucencies and articular surface defects; 6). Sample blocks of SCB plate and TBB were collected from the distopalmar aspect of both condyles and the sagittal ridge and examined via 3-D micro-computed tomography at 45-?m isotropic voxel resolution. For each sample, the angle between the principal orientation of trabeculae and the sagittal plane and the degree of anisotropy (DA) were calculated from mean intercept length measurements.

Results—Condylar samples had significantly lower angle (mean, 8.9°; range, 73° to 10.9°) than sagittal ridge samples (mean, 40.7°; range, 33.6° to 49.2°), TBB had significantly higher DA (mean ± SE, 1.75 ± 0.04) than SCB plate (1.29 ± 0.04), and mildly diseased TBB had higher DA (1.85 ± 0.06) than severely diseased TBB (1.65 ± 0.06).

Conclusions and Clinical Relevance—The highly ordered appearance of trabeculae within the condyles supports the concept that joint loading is primarily transmitted through the condyles and not the sagittal ridge. The sharp changes in the trajectories of the SCB trabeculae at the condylar grooves may be indicative of hypothetical tensile forces at this location contributing to the pathogenesis of condylar fractures. (Am J Vet Res 2010;71:1148—1153)

Abstract

Objective—To determine the anisotropic characteristics of the microarchitecture of the subchondral bone (SCB) plate and trabecular bone (TBB) of the distopalmar aspect of the metacarpal condyles in horses with different stages of SCB disease.

Sample Population—12 third metacarpal bone pairs from racing Thoroughbreds euthanized for diverse reasons.

Procedures—Both metacarpi were collected from horses with SCB changes that were mild (sclerosis and focal radiolucencies; n = 6) or severe (multifocal radiolucencies and articular surface defects; 6). Sample blocks of SCB plate and TBB were collected from the distopalmar aspect of both condyles and the sagittal ridge and examined via 3-D micro-computed tomography at 45-?m isotropic voxel resolution. For each sample, the angle between the principal orientation of trabeculae and the sagittal plane and the degree of anisotropy (DA) were calculated from mean intercept length measurements.

Results—Condylar samples had significantly lower angle (mean, 8.9°; range, 73° to 10.9°) than sagittal ridge samples (mean, 40.7°; range, 33.6° to 49.2°), TBB had significantly higher DA (mean ± SE, 1.75 ± 0.04) than SCB plate (1.29 ± 0.04), and mildly diseased TBB had higher DA (1.85 ± 0.06) than severely diseased TBB (1.65 ± 0.06).

Conclusions and Clinical Relevance—The highly ordered appearance of trabeculae within the condyles supports the concept that joint loading is primarily transmitted through the condyles and not the sagittal ridge. The sharp changes in the trajectories of the SCB trabeculae at the condylar grooves may be indicative of hypothetical tensile forces at this location contributing to the pathogenesis of condylar fractures. (Am J Vet Res 2010;71:1148—1153)

Contributor Notes

Dr. Rubio-Martinez's present address is the Department of Companion Animal Clinical Studies, Faculty of Veterinary Science. University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.

Dr. Cruz's present address is Paton and Martin Veterinary Services, 25930 40th Ave, Aldergrove, BC V4W 2A5, Canada.

Supported by the Ontario Horse Racing Industry Association (OHRIA) and the Ontario Ministry of Agriculture, Food and Rural Affairs. Canada. The Spanish Ministry of Education and Science (MEC) provided stipend funding for Dr. Rubio-Martínez during the study.

Presented at the meetings of the American College of Veterinary Surgeons, San Diego, October 2008 and European College of Veterinary Surgeons, Nantes, France, July 2009.

The authors thank Gabrielle Monteith for assistance with statistical analysis.

Address correspondence to Dr. Rubio-Martínez (luis.rubiomartinez@up.ac.za).