Radiographic evaluation of changes in the proximal phalanx of Thoroughbreds in race training.
OBJECTIVE
To evaluate changes in the cortical bone of the proximal phalanx of the fore-limbs of Thoroughbreds in response to training.


METHODS
Twenty-seven 2-year-old Thoroughbreds (20 females, 2 males, and 5 geldings).


METHODS
Horses were principally in training for races in a straight line and in a clockwise direction. Lateromedial and dorsopalmar radiographic views of each metacarpophalangeal joint were obtained before the horses started training and 1 year after starting exercise and racing. Width of the dorsal, palmar, lateral, and medial cortex and the width and thickness of the medulla were measured. Ratios (rather than absolute values) were used to remove the effect of differences in bone size among horses.


RESULTS
10 horses were lost from the study. Radiographs were obtained for 17 horses 1 year after starting training (9 horses raced in a clockwise direction, and 8 raced in clockwise and counterclockwise directions). There was no difference between the cortical bone in the right and left forelimbs at the start of the study. After training for 1 year, the palmar cortex in the right forelimb was significantly thicker than that in the left forelimb.


CONCLUSIONS
The strain patterns, biomechanics of rapid exercise, and type of training most probably determined differences in the adaptive responses of the proximal phalanx. The data reported here can be used in the evaluation of weight-bearing distribution along the proximal phalanx and evaluation of the relationship between exercise and bone remodelling of the proximal phalanx.
Equine Research Centre, Department of Veterinary Pathology, Diagnostic and Clinic, Faculty of Veterinary Medicine, University of Perugia, 00126, Perugia, Italy. francescabeccati@hotmail.it
Francesca
F
Beccati
Marco
M
Pepe
Antonio
A
Di Meo
Sveva
S
Davanzo
Franco
F
Moriconi
D000818:Animals; D016723:Bone Remodeling; D005260:Female; D005552:Forelimb / Q000000981:diagnostic imaging / Q000502:physiology; D006736:Horses / Q000033:anatomy & histology*; D008297:Male; D010805:Physical Conditioning, Animal; D011859:Radiography; D050277:Toe Phalanges / Q000000981:diagnostic imaging* / Q000502:physiology*; D016474:Weight-Bearing