What Causes Swollen And Painful Ring Fingers And Toe?

My wife is sufferring from swollen & painful ring fingers along with a swollen/painful toe on her right foot. Doctors see fluid in and around her toe bone (MRI results) with no other indications. She has suffered from AVN and had a bilateral hip replacement in her 40's and we are trying desperately to find out what is now causing this extreme pain in her fingers and foot. She does not meet the criteria of suspect symtoms and we are baffled. Blood work comes back normal, has seen two family docs, a rheumatologist, and has appointments scheduled with another doc but all we keep getting is that -- it's a mystery. Is there a specialty doctor for such symtoms & or AVN?