Mechanisms of joint damage in an experimental model of hemophilic arthritis.

Autologous whole blood was injected into the knee joints of rabbits 3 times each week for 12 weeks. The resulting destructive arthritis showed macroscopic and microscopic changes similar to those described in hemophilic arthritis in humans. Immunofluorescence studies indicated that a specific immune response is probably not involved in the pathogenesis of hemophilic arthritis. Detailed histopathologic examinations of knee joints in both the early and the late phase of arthritis revealed an obvious synovial and cartilage iron load, in the absence of inflammatory changes. The implications of these findings in the pathogenesis of destructive cartilage changes are discussed.