Site-specific adaptive remodeling of Greyhound metacarpal cortical bone subjected to asymmetrical cyclic loading

Kenneth A. Johnson Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210-1089.
Department of Clinical Veterinary Science, School of Veterinary Science, University of Bristol, Langford, Bristol, BS40 5DU, UK.

Search for other papers by Kenneth A. Johnson in
Current site
Google Scholar
PubMed
Close
 MVSc, PhD
,
Gerry A. Skinner Department of Clinical Veterinary Science, School of Veterinary Science, University of Bristol, Langford, Bristol, BS40 5DU, UK.

Search for other papers by Gerry A. Skinner in
Current site
Google Scholar
PubMed
Close
 PhD
, and
Peter Muir Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Peter Muir in
Current site
Google Scholar
PubMed
Close
 MVetClinStud, PhD

Abstract

Objective—To quantify geometric, inertial, and histomorphometric properties at the mid-diaphyseal level of left and right metacarpal bones (MCB) of racing Greyhounds.

Sample Population—MCB from 7 racing Greyhounds euthanatized for reasons unrelated to MCB abnormalities.

Procedures—Mid-diaphyseal transverse sections of left and right MCB were stained with H&E or microradiographed. Images of stained sections were digitized, and cross-sectional area, cortical area, and maximum and minimum area moments of inertia of each bone were determined. Histomorphometric data (osteonal density, osteonal birefringence, and endosteal new lamellar bone thickness) were collected in 4 quadrants (dorsal, palmar, lateral, medial). Values were compared between limbs and among bones and quadrants.

Results—Cross-sectional area, cortical area, and maximum and minimum moments of inertia of left MCB-IV and -V were significantly greater, compared with contralateral bones. Overall osteonal densities in the dorsal quadrants of left MCB were greater, compared with lateral and medial quadrants. Also, percentage of birefringent osteons was significantly greater in the dorsal quadrant of left MCB-III, -IV, and -V, compared with the palmar quadrant. Thickness of new endosteal lamellar bone was not significantly influenced by limb, bone, or quadrant.

Conclusions and Clinical Relevance—Increased cortical thickness and geometric properties of left MCB-IV and -V of Greyhounds, together with altered turnover and orientation of osteons in the dorsal quadrants of left MCB, are site-specific adaptive responses associated with asymmetric cyclic loading as a result of racing on circular tracks. Site-specific adaptive remodeling may be important in the etiopathogenesis of fatigue fractures in racing Greyhounds. (Am J Vet Res 2001;62:787–793)

Abstract

Objective—To quantify geometric, inertial, and histomorphometric properties at the mid-diaphyseal level of left and right metacarpal bones (MCB) of racing Greyhounds.

Sample Population—MCB from 7 racing Greyhounds euthanatized for reasons unrelated to MCB abnormalities.

Procedures—Mid-diaphyseal transverse sections of left and right MCB were stained with H&E or microradiographed. Images of stained sections were digitized, and cross-sectional area, cortical area, and maximum and minimum area moments of inertia of each bone were determined. Histomorphometric data (osteonal density, osteonal birefringence, and endosteal new lamellar bone thickness) were collected in 4 quadrants (dorsal, palmar, lateral, medial). Values were compared between limbs and among bones and quadrants.

Results—Cross-sectional area, cortical area, and maximum and minimum moments of inertia of left MCB-IV and -V were significantly greater, compared with contralateral bones. Overall osteonal densities in the dorsal quadrants of left MCB were greater, compared with lateral and medial quadrants. Also, percentage of birefringent osteons was significantly greater in the dorsal quadrant of left MCB-III, -IV, and -V, compared with the palmar quadrant. Thickness of new endosteal lamellar bone was not significantly influenced by limb, bone, or quadrant.

Conclusions and Clinical Relevance—Increased cortical thickness and geometric properties of left MCB-IV and -V of Greyhounds, together with altered turnover and orientation of osteons in the dorsal quadrants of left MCB, are site-specific adaptive responses associated with asymmetric cyclic loading as a result of racing on circular tracks. Site-specific adaptive remodeling may be important in the etiopathogenesis of fatigue fractures in racing Greyhounds. (Am J Vet Res 2001;62:787–793)

All Time Past Year Past 30 Days
Abstract Views 66 0 0
Full Text Views 804 629 196
PDF Downloads 199 96 9
Advertisement