Degenerative Joint Disease

(DJD)

DJD in a horse (Image sourced from Bristol Biomed Image Archive with permission)

• Osteoarthritis, osteoarthrosis
• Due to acceleration of normal ageing process - wear and tear
• Destructive disease leading to:
  • Loss of weight-bearing articular cartilage
  • Erosion, fibrillation of cartilage
    • Clefts in the cartilage, perpendicular to the surface
  • Complete exposure of underlying bone
    • Bone appears polishes, dense - eburnation
    • Radiographically - joint space reduction due to loss of cartilage
  • Osteophyte formation at joint margins
  • Remodelling of adjacent bone
  • Brown/yellow discolouration
  • Synovial hypertrophy
  • Capsular fibrosis
• May affect one or multiple joints
• May or may not be symptomatic
• Pathogenesis:
  • Not entirely clear but linked to loss of proteoglycans and subsequent lubrication
  • Increased water content due to improper binding -> softening of cartilage = chondromalacia

• Predisposing factors:
  • Persistent trauma
  • Joint instability / dysplasia
    • Luxations and subluxations
    • Hip dysplasia
    • Elbow dysplasia
  • Conformational abnormalities / congenital malformations
  • Osteochondrosis dissecans
  • Intra-articular fractures
  • Calve Legg-Perthe's disease