Advertisement

Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures

Catherine L. RadtkeComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Catherine L. Radtke in
Current site
Google Scholar
PubMed
Close
 BS
,
Nichole A. DanovaComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Nichole A. Danova in
Current site
Google Scholar
PubMed
Close
 DVM
,
Mary C. ScollayComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Mary C. Scollay in
Current site
Google Scholar
PubMed
Close
 DVM
,
Elizabeth M. SantschiComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Elizabeth M. Santschi in
Current site
Google Scholar
PubMed
Close
 DVM
,
Mark D. MarkelComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Mark D. Markel in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Támara Da Costa GómezComparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Támara Da Costa Gómez in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Peter MuirComparative Orthopaedic Research Laboratory, 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
 BVSc, MVetClinStud, PhD

Abstract

Objective—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 highspeed exercise.

Sample Population—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.

Procedure—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 and Clinical Relevance—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. (Am J Vet Res 2003;64:1110–1116)

Abstract

Objective—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 highspeed exercise.

Sample Population—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.

Procedure—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 and Clinical Relevance—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. (Am J Vet Res 2003;64:1110–1116)