Protracted familial Mediterranean fever arthritis.

Familial Mediterranean fever (FMF) is an inherited disorder characterized by recurrent attacks of fever and abdominal, chest, and articular pain. The articular attack of FMF is typically an acute, self-limited, large joint monoarthritis most often affecting the knee or hip. Rarely, a more protracted arthritis may occur. We describe two unusual cases of long-standing FMF arthritis with excellent response to synovectomy.