title: Racing prognosis after cumulative stress-induced injury of the distal portion of the third metacarpal and third metatarsal bones in Thoroughbred racehorses: 55 cases (2000-2009).
abstract: OBJECTIVE
  To evaluate the diagnostic features, results of free-choice exercise treatment, prognosis, and postinjury racing performance of Thoroughbred racehorses with cumulative stress-induced bone injury (CSBI) of the distal portion of the third metacarpal and third metatarsal bones (MC3/MT3).
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  55 Thoroughbred racehorses with CSBI of the distal portion of MC3/MT3.
  
  
  METHODS
  Data on signalment, history, and radiographic, scintigraphic, and lameness examination findings were reviewed. Horses with lameness localized to the distal portion of MC3/MT3, and that did not have concurrent lameness but did have radiographic and nuclear scintigraphic changes consistent with CSBI, were included in the study. Information on pre-and postinjury racing performance was acquired from race records.
  
  
  RESULTS
  Mean age was 3.2 years (median, 3 years [range, 2 to 6 years]). Ninety-five percent (52/55) of horses with CSBI raced after injury. Males were more commonly affected (75% [41/55]) than were females (25% [14/55]; odds ratio, 3.99 [95% confidence interval, 2.17 to 7.34]). There was no significant difference in postinjury total earnings, compared with total earnings before injury; horses had significantly more starts and less earnings per start after injury. Median time to first start after injury was 194 days. Of 45 horses that raced before and after injury, 31 % (14/45) had an increase in racing class, 31 % (14/45) had no change in class, and 38% (17/45) had a decrease in class.
  
  
  CONCLUSIONS
  Thoroughbred racehorses with CSBI of the distal portion of MC3/MT3 treated with free-choice exercise had a favorable prognosis with no appreciable decrease in class or performance.
authors.affiliation: Rood and Riddle Equine Hospital, Lexington, KY 40580, USA. ttull@roodandriddle.com
authors.forename: Travis M
authors.initials: TM
authors.lastname: Tull
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Bramlage
mesh_terms: D000818:Animals; D005260:Female; D005552:Forelimb / Q000473:pathology; D015775:Fractures, Stress / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000473:pathology; D006736:Horses / Q000293:injuries*; D007794:Lameness, Animal; D008297:Male; D050279:Metacarpal Bones / Q000473:pathology; D008682:Metatarsal Bones / Q000473:pathology; D010805:Physical Conditioning, Animal; D013177:Sports