Hypothesis 3 Ð Degenerative

Infectious arthritis Ð Radiographic change similar to any non-errosive joint disease.  
Polyauricular infectious arthritis Ð secondarily occurs to bacteremia caused by isolated 
infection or in conjunction with systemic disease.  Monoarticular inf arth. Can result from 
traumatic injury.  Early rad signs include synovial effusion, increase synovial mass, soft 
tissue swelling _ indicated by distended joint capsule.

Rheumatoid arthritis Ð Occurs in small/toy breed dogs 8mo. To 8 yrs of age, 
accompanied by fever, malaise, anorexia and lymphadenopathy in earlier stages.  
Prominent lesion is destruction of subchondral bone.  Subluxation/luxation may occur.  
Synovial fluid changes are indicative of inflammatory synovitis.  Disease responds 
temporarily to corticosteroids.  Rad. Changes occur in distal joints of extremities.  Prox. 
Large joints like stifle are affected.  Synovial effusion happens first, along with non-
specific soft-tissue swelling around affected joints.  

Muscle injury leading to contractive patella luxation ÐscarringÉ