Watch Caitlin’s video of her experiences with hip replacement.

Ask Caitlin Ryan to name her favorite subject in school and she doesn’t hesitate – it’s dance.

“Right now we are doing hip hop. We’ve done world dance and ballet,” Caitlin says. “It’s amazing because I’ve never been able to really dance like there’s nothing wrong.”

Caitlin may be forgiven if dancing shoes hold more appeal than schoolbooks this year. Because while her classmates spent their summer vacations going to the swimming pool and the beach, Caitlin, age 11, was undergoing hip replacement surgery.

Caitlin is one of an estimated 300,000 children in the U.S. who have juvenile arthritis, or JA. At age 3, she was diagnosed with juvenile rheumatoid arthritis, or JRA, the most common form of arthritis among children. This autoimmune disease, which affects an estimated 50,000 children, causes the body to attack its own joints and organs. The symptoms ebb and flare, often without warning or explanation. Additionally, it dramatically affects physical mobility and may lead to blindness.

“When they first said it was arthritis I was a little bit relieved it wasn’t cancer,” says Caitlin’s mother, Colleen Ryan. “But the more I learned about it, the more devastating the diagnosis became because her [case] is one of the most severe. She has it in every joint.”

It’s not known what causes the condition, and there is no known cure. It goes into remission for some children but lasts into adulthood for many more.

Caitlin’s rheumatologist, Andreas Reiff, MD, Associate Professor of Clinical Rheumatology at the Children’s Hospital Los Angeles, says 80 to 85 percent of JRA patients respond well to medication and find relief.

Special Challenges

Dr. Reiff says these newer medications are so effective that the number of joint replacement surgeries his hospital has performed on pediatric patients has dropped dramatically. Since 2000, Children’s Hospital Los Angeles has only done eight to 10 joint replacement surgeries compared with the 15 to 18 the hospital did yearly until 1999.

That’s good news, because joint replacement poses special challenges for younger patients.

Their bones are smaller, so it’s often difficult for doctors to find replacement parts that are the right size. Components sometimes have to be custom designed and built for children.

Additionally, replacement joints wear out over time, meaning that most who have their joints replaced at young ages will likely need a second or even third surgery later in life. For each subsequent surgery, less of the patient’s natural bone remains, making it an increasingly difficult and complicated procedure.

What’s more, replacing joints destroys the growth plates in bones, which stalls a child’s development and sometimes limits height.