Total joint replacement may be considered as a last resort for joints that have been so badly damaged by juvenile rheumatoid arthritis (JRA) that walking is very difficult or impossible. The hip and the knee joints are the most commonly replaced. Results can be very good in teens who have total joint replacement.
In general, it is best to delay total joint replacement until your child's bones have stopped growing. However, the possible risks of waiting must also be considered. Waiting may lead to worsening of the joint and surrounding tissues.
Joint replacement surgery can relieve pain and restore function, but it will not restore the joint to a normal condition.
If both hips and knees need to be replaced, hips are done first because it is difficult to rehabilitate the knee if there is not good function in the hip.
See the topic Osteoarthritis for more information on total knee and hip replacement surgery.
WebMD Medical Reference from Healthwise