title: Characterization of experimentally induced post-traumatic osteoarthritis in the medial femorotibial joint of horses.
abstract: OBJECTIVE
  To study osteoarthritis in the equine medial femorotibial (MFT) joint after a single traumatic injury.
  
  
  METHODS
  10 mature horses.
  
  
  METHODS
  In vitro explant cultures were used to determine injury threshold for stifle joint cartilage. Contusive impacts were applied to the medial femoral condyle (MFC), and horses were followed for 84 (n = 5) and 180 days (5). Synovial fluid samples were collected every 14 days for determination of sulphated glycosaminoglycan (sGAG) concentrations. Radiographic and lameness evaluations were performed. Gross and histologic descriptions, and immunohistochemistry, cartilage sGAG content determination, and cartilage aggregate modulus determination were performed at the MFC impact site (MFCi), MFC nonimpact site (MFCn), and medial tibial plateau (MTP).
  
  
  RESULTS
  Synovial fluid sGAG concentration decreased significantly on days 14, 28, 42, and 56 in all horses. Macroscopic and microscopic articular lesions developed within all MFT joints. No radiographic abnormalities were observed. Mild lameness was evident in several horses. No significant differences were found between short-term and longterm cohorts of horses with respect to histologic scores and TUNEL results. On immunohistochemistry, MFCi was positive for COL2-(3/4)C(short). International Cartilage Repair Society scores differed significantly between short-term and long-term cohorts of horses. In all horses, sGAG concentrations were significantly decreased at the MFCi, compared with the MFCn.
  
  
  CONCLUSIONS
  Use of contusive impacts on the MFC of horses results in cartilage lesions that are similar to those described clinically, supporting trauma as a contributing factor in the natural pathogenesis of osteoarthritis.
authors.affiliation: Ontario Veterinary College, Comparative Orthopaedic Research Group, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Courtney J
authors.initials: CJ
authors.lastname: Bolam
authors.forename: Mark B
authors.initials: MB
authors.lastname: Hurtig
authors.forename: Antonio
authors.initials: A
authors.lastname: Cruz
authors.forename: Beverly J E
authors.initials: BJ
authors.lastname: McEwen
mesh_terms: D000818:Animals; D006025:Glycosaminoglycans / Q000378:metabolism; D006614:Hindlimb; D006734:Horse Diseases / Q000378:metabolism / Q000473:pathology*; D006736:Horses; D007596:Joints / Q000473:pathology*; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D006025:Glycosaminoglycans