title: Prevalence of naturally occurring cartilage defects in the ovine knee.
abstract: OBJECTIVE
  To determine the prevalence, anatomical location and severity of cartilage defects in the stifle (knee) within a population of adult ewes (N = 65).
  
  
  METHODS
  Articular cartilage (AC) of the distal femur, proximal tibia and patella was assessed using Osteoarthritis Research Society International (OARSI) recommendations for macroscopic and microscopic scoring of ovine cartilage. Synovial fluid analysis and histology of the synovial membrane were performed. All limbs were examined by computed tomography.
  
  
  RESULTS
  Twenty-eight sheep (n = 28; 43%) presented at least one score 2 or score 3 lesion. Twenty-two (n = 22; 34%) sheep were macroscopically normal. Most frequent localizations of lesions were: axial aspect of the central third of the medial tibial condyle (32.7% of the lesions), middle third of the medial femoral condyle (29.4%), middle third of the articular surface of the patella (9.8%), and axial aspect of the central third of the lateral tibial condyle (9.8%). Grade of macroscopic lesions was significantly (H (3) = 29.31, P 0.000) affected by age. Macroscopic score correlated well with histological changes that can be found in osteoarthritis (OA) (r 0.83; P 0.000). Neither clinical signs of OA, nor cytological and histological signs of inflammation were identified, while imaging abnormalities were very rare.
  
  
  CONCLUSIONS
  Our data seem to indicate that naturally occurring OA exists in ageing sheep, at least subclinically. It might be useful to take into account prevalent cartilage defects at baseline in studies using ovine models.
authors.affiliation: Integrated Veterinary Research Unit, Namur Research Institute for Life Sciences, Department of Veterinary Medicine, University of Namur, Belgium. jean-michel.vandeweerd@fundp.ac.be
authors.forename: J-M
authors.initials: JM
authors.lastname: Vandeweerd
authors.forename: F
authors.initials: F
authors.lastname: Hontoir
authors.forename: N
authors.initials: N
authors.lastname: Kirschvink
authors.forename: P
authors.initials: P
authors.lastname: Clegg
authors.forename: J-F
authors.initials: JF
authors.lastname: Nisolle
authors.forename: N
authors.initials: N
authors.lastname: Antoine
authors.forename: P
authors.initials: P
authors.lastname: Gustin
mesh_terms: D017677:Age Distribution; D000375:Aging / Q000473:pathology; D000818:Animals; D001530:Belgium / Q000453:epidemiology; D001835:Body Weight / Q000502:physiology; D002357:Cartilage Diseases / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005269:Femur / Q000473:pathology; D010003:Osteoarthritis / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D010329:Patella / Q000473:pathology; D015995:Prevalence; D012720:Severity of Illness Index; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000473:pathology; D034561:Sheep, Domestic; D013264:Stifle / Q000473:pathology*; D013582:Synovial Fluid / Q000737:chemistry; D013583:Synovial Membrane / Q000473:pathology; D013977:Tibia / Q000473:pathology
keywords: Cartilage defects; Knee; Prevalence; Sheep; Stifle