AAOS: Joint Replacements in Juvenile Arthritis Prove Well Worth Risks

Enough patients with juvenile arthritis have now had joint replacements to reach conclusions, and these were reported at the American Academy of Orthopedic Surgeons meeting this week in Chicago.

The great majority of total knee replacements (TKRs) last for at least two decades, according to a multicenter study, and the search is on for custom joints that fit even better. A small longitudinal study of the reasons for artificial hip joint replacement in these patients revealed the main reasons for failure, due to older materials, oversized devices, and compromised native bone.

The multicenter study of TKRs, reported by Mark Figgie MD of the Hospital for Special Surgery (HSS) in New York, analyzed outcomes for 217 patients treated at four major osteopathic surgery centers in the US (HSS, Brigham & Womens, Stanford, and University of California San Francisco) and one in Belgium. The average age at surgery was 28.

The 10-year survival rate for the knee grafts was 92%, and 75% lasted for 20 years without need for revision. Among cases available for assessment, almost half reported unlimited walking ability, another 22% could walk up to ten blocks, and 89% could manage stairs without using a railing.

These results are not quite as good as those for TKR in older patients with osteoarthritis, said Dr. Figgie, who is chair of arthritis surgery at HSS, adding that this is no surprise given these young patients' poor bone quality, use of immunosuppressive drugs, and comparatively small size.

"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," he said in a press release. "The better the implant fits, the better it should function and the longer it should last."

Also reported at the meeting were results from a prospective series of 24 revisions of total hip arthroplasty among 15 patients with juvenile arthritis treated at Stanford. Seven hips required a second revision, reported Stuart Goodman MD and coworkers, most of them due to loosening and osteolysis. Two patients had deep infection requiring reoperation, and at least four developed fractures long after surgery.

Revision surgery is "very challenging" in this group, they reported, and late complication rates are relatively high. Cementless implants may improve these outcomes for the future, they predicted.