Effect of focused and radial extracorporeal shock wave therapy on equine bone microdamage.
OBJECTIVE
To determine whether bone microcracks are altered after application of focused and radial extracorporeal shock wave therapy (ESWT) to the equine distal limb.


METHODS
An ex vivo experimental model.


METHODS
A contralateral limb specimen was obtained from 11 Thoroughbred racehorses with a unilateral catastrophic injury. Distal limb specimens were also obtained from 5 non-racing horses.


METHODS
Three separate skin-covered bone segments were obtained from the mid-diaphysis of the metacarpus (MC3) or metatarsus (MT3). Focused (9,000 shockwaves, 0.15 mJ/mm2, 4 Hz) and radial (9,000 shockwaves, 0.175 mJ/mm2, 4 Hz) ESWT treatments were randomized to the proximal and distal segments and the middle segment was used as a treatment control for pre-existing microcracks. After treatment, bone specimens were bulk-stained with basic fuchsin and microcracks were quantified in transverse calcified bone sections.


RESULTS
ESWT had small but significant effects on microcracks. Microcrack density (Cr.Dn) and microcrack surface density (Cr.S.Dn) were increased after focused ESWT, whereas Cr.Le was increased after radial ESWT. In racing Thoroughbreds, Cr.Le increased with increased number of races undertaken. Cr.Dn and Cr.S.Dn were not significantly influenced by the number of races undertaken.


CONCLUSIONS
ESWT has small but significant effects on bone microcracking ex vivo.


CONCLUSIONS
These preliminary data suggest that ESWT has the potential to increase bone microcracking in equine distal limb bone in vivo. Such effects may be more pronounced in Thoroughbreds that are actively being raced, because in vivo microcracking increases with increased number of races undertaken.
Da Costa Gómez
Támara M
TM
Comparative Orthopaedic Research Laboratory, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.
Radtke
Catherine L
CL
Kalscheur
Vicki L
VL
Swain
Carol A
CA
Scollay
Mary C
MC
Edwards
Ryland B
RB
Santschi
Elizabeth M
EM
Markel
Mark D
MD
Muir
Peter
P
D000818:Animals; D005260:Female; D005552:Forelimb / Q000293:injuries; D017102:Fracture Healing / Q000528:radiation effects*; D050723:Fractures, Bone / Q000473:pathology / Q000628:therapy / Q000662:veterinary*; D019220:High-Energy Shock Waves / Q000627:therapeutic use*; D006614:Hindlimb / Q000293:injuries; D006736:Horses / Q000293:injuries*; D008297:Male; D010805:Physical Conditioning, Animal