Long Live Knee Replacements in the Young!

Total knee replacements for juvenile idiopathic arthritis last for decades in most patients

(RxWiki News) People typically think knee replacement surgery is only for older adults with arthritis. But the surgery is also used for young patients when joint damage has become severe.

Because knee replacement surgery is fairly rare in younger patients, there is little evidence on how long the joint replacements last.

Recently, researchers found knee replacements did not last as long in young patients with juvenile idiopathic arthritis (JIA) as they do in older osteoarthritis patients.

Still, the procedure can be a life-changer for many patients with JIA – a painful disease that affects children.

In patients with JIA, about 92 percent of knee replacements lasted 10 years and a little over 75 percent lasted 20 years.

"Research joint repair options."

The study was conducted by Mark P. Figgie, MD, of the Hospital for Special Surgery in New York, and colleagues.

Total knee replacement is a largely successful surgery for the treatment of severe knee arthritis in older adults. While knee replacement surgery is an uncommon treatment for patients with JIA, it is sometimes used to relieve pain and improve mobility in these younger patients.

"The surgery in this patient population, although performed by only a small number of highly specialized orthopedic surgeons nationwide, is life changing for JIA patients," said Dr. Figgie in a press statement.

"Joint replacement can free patients – many of them adolescents – from a life of unrelenting pain. It can enable those in a wheelchair to walk again, giving many a new lease on life," he said.

"Juvenile arthritis is a debilitating condition that can really affect the patient's ability to function, yet few reports exist on the results of total knee replacement in people with JIA," Dr. Figgie went on to explain.

In light of this limited research, Dr. Figgie and colleagues set out to assess the longevity of total knee replacements in younger patients with JIA.

Because knee replacement is a rare procedure for younger patients, the researchers looked at an international population of JIA patients who had undergone total knee replacement.

The study included 217 patients who had undergone a total of 335 knee replacements, or total knee arthroplasty. Participants were treated at five hospitals between 1979 and 2011. 

While all patients had been diagnosed with JIA, some were much past childhood when they underwent surgery. Patients' ages ranged from 11 to 58, with an average age of 28.1.

Results showed that the 10-year knee implant survival rate among JIA patients was 92.2 percent. The 20-year implant survival rate was 75.5 percent.

"While the implants lasted at least 10 years in 92 percent of JIA patients, the data show total knee replacements last slightly longer in elderly patients with osteoarthritis," Dr. Figgie noted. 

"This is not really surprising, as the longevity of the implant may be affected by the JIA patient's poor bone quality, severe joint deformities and contractures (abnormal shortening of muscle tissue), and the immunosuppressive medications used to treat their disease," he explained.

The researchers also measured patients' walking tolerance (ability to stay on one's feet while moving), ability to go up and down stairs and use of walking aids after surgery.

Results showed 49 percent of the patients studied had unlimited walking tolerance.

While 27 percent of patients could only walk less than five blocks, 22 percent could walk five to 10 blocks.

The researchers also found that, over the 32-year study period, the number of knee replacements performed per year remained relatively steady, even as new arthritis medications were developed during those years.

According to Dr. Figgie, further research will evaluate the different types of knee implants to see which ones work best for younger arthritis patients. Specifically, researchers will compare standard implants to custom implants specially designed for young JIA patients.

"One of the reasons I launched the study is to make sure we have continued access to custom implants if they are needed for a younger patient," Dr. Figgie said.

"The better the implant fits, the better it should function, and the longer it should last. When you're operating on a 12-year-old and using something they will have in their knee for the rest of their life, you want it to be as perfect as possible," he said.

Dr. Figgie's recent research was presented March 19 at the annual meeting of the American Academy of Orthopaedic Surgeons. The study has yet to be published in a peer-reviewed journal.

Review Date: 
March 21, 2013