rheumatoid arthritis ,recovery,total hip replacement,knee replacement

my mother is 52 and she has been a rheumatoid arthritis patient for past 20years...she underwent total hip joint replacement in april 2006 followed by total knee joint replacement in september 2006...since then she has been undergoing regular physiotherapy at home..but still her recovery has not been much..she still has 2 wear an immobiliser and get stretching done to walk...i wanna know if total recovery is possible for her so that her legs are straight and she can walk like normal people without immobiliser...? And if u have any special exercises or treatment suggestions that can be of help to her...will be really thankful to you since we as a family are realy waiting to see her back on her feet once again...thanks a bunch