Hypothesis 2: lnfectious arthritis Contamination of joint with bacteria can lead to innoculation of synovial membrane or fluid. This will result in an inflammatory reaction. Bacterial colonization will result in loss of proteoglycan and collagen from articular cartilage. The loss of support coupled with mechanical trauma leads to rapid cartilage destruction. These effects may become irreversible and progressive and lead to oseoarthritis. Possible routes of entry of the bacteria include: hematogenous (umbilicus), extension of osteomyelitis from adjacent epiphysis or metaphysis, trauma, or iatrogenic.