title: Magnetic resonance imaging-detected adaptation and pathology in the distal condyles of the third metacarpus, associated with lateral condylar fracture in Thoroughbred racehorses.
abstract: BACKGROUND
  Lateral condylar (LC) fractures of the third metacarpus (McIII) are a common reason for euthanasia in racehorses, and may be the result of repetitive overloading or cumulative pathological change. Magnetic resonance imaging (MRI) allows monitoring of bone and cartilage to detect pathological and adaptive changes that may be precursors of fracture.
  
  
  OBJECTIVE
  To describe bone and cartilage MRI features in the distal condyles of McIII of Thoroughbred racehorses, with and without condylar fracture.
  
  
  OBJECTIVE
  1) A greater degree of bone and cartilage adaptation or pathology will be seen in fractured McIIIs compared with their respective contralateral McIIIs. 2) Contralateral McIIIs will have a greater degree of bone and cartilage adaptation or pathology than McIIIs from control horses that did not sustain a LC fracture.
  
  
  METHODS
  The McIIIs from 96 horses subjected to euthanasia at racecourses were divided into 3 groups: Group 1: nonfractured bones from horses without LC fracture; Group 2: nonfractured bones from horses with unilateral LC fracture; and Group 3: fractured bones from horses with unilateral LC fracture. The MR images were examined and graded for bone and cartilage changes.
  
  
  RESULTS
  Nine percent of Group 1 (n = 9) and 11% of Group 2 bones (n = 5) had incomplete LC fractures. Focal palmar necrosis was most frequently detected in bones from Group 1 (12%) compared with Groups 2 (9%) and 3 (4%). The prevalence of bone and/or cartilage abnormalities tended to increase from Group 1 to Group 2 to Group 3.
  
  
  CONCLUSIONS
  Magnetic resonance imaging is able to detect cartilage and bone changes that may be associated with LC fracture. There was no significant difference in bone/cartilage changes between bones from Groups 1 and 2, despite increased pathology in Group 2 bones.
  
  
  CONCLUSIONS
  Periodic monitoring of bone and/or cartilage changes in distal McIII of Thoroughbred racehorses may help to prevent catastrophic LC fractures.
authors.affiliation: Centre for Equine Studies, Animal Health Trust, Suffolk, UK. carolyne.tranquille@aht.org.uk
authors.forename: C A
authors.initials: CA
authors.lastname: Tranquille
authors.forename: T D H
authors.initials: TD
authors.lastname: Parkin
authors.forename: R C
authors.initials: RC
authors.lastname: Murray
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001842:Bone and Bones / Q000502:physiology; D002356:Cartilage / Q000502:physiology; D005260:Female; D050723:Fractures, Bone / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D008297:Male; D050279:Metacarpal Bones / Q000473:pathology*; D012420:Running; D013177:Sports