Recurrent effusion of the knee joint.
D001172:Arthritis, Rheumatoid / Q000150:complications; D006801:Humans; D006833:Hydrarthrosis / Q000209:etiology / Q000601:surgery / Q000628:therapy*; D007717:Knee / Q000601:surgery; D007719:Knee Joint; D010003:Osteoarthritis / Q000150:complications; D013585:Synovitis / Q000150:complications