Hemarthrosis associated with sodium warfarin.

Three patients developed an acute hemarthrosis related to sodium warfarin. Synovial aspiration was well tolerated and necessary to substantiate the diagnosis. Prior joint disease was present in two but in only one was there a definite precipitating event, namely minor trauma. The prothrombin time was within the therapeutic range in two of the three. The acute synovitis subsided after the warfarin was discontinued. Joint function seems to have fully returned but long-term evaluation is needed.