Joint replacement improves lives of RA patients

TWO new studies by researchers at Hospital for Special Surgery have shed light on joint replacement outcomes in patients with rheumatoid arthritis (RA). One study overturns the common belief that RA patients have worse outcomes after a total knee replacement (TKR) than patients who undergo the operation for osteoarthritis. The other study demonstrates that RA patients who undergo a total hip replacement were as likely to have significant improvements in function and pain as patients with osteoarthritis (OA), even though they did not do as well.

The studies were made possible by the Hospital for Special Surgery (HSS) Total Joint Replacement Registry. Started in 2007, this prospective registry includes a gold mine of information including data on all patients who seek care at HSS for knee and hip replacement surgery. “Other hospitals have registries, but what we have is an incredible volume of information on patients that allows us to do interesting studies, because there are so many patients having hip and knee replacement surgeries at our hospital,” said Susan Goodman, M.D., lead author of both studies and a rheumatologist at Hospital for Special Surgery in New York City.

Historically, RA patients have had worse outcomes after joint replacement surgeries, however, whether this was caused by poorly controlled disease or disease treatment was unclear. Starting in the 1980s, effective disease-modifying drugs became available to treat patients with RA. In the late 1990’s, etanercept, infliximab, and other biologic medication came on the market. Today, at HSS over 70% of patients are on disease modifying drugs and over 50% are on biologics.

In the two new studies, investigators at Special Surgery set out to examine whether outcomes remained worse for RA patients in a cohort with a high prevalence of potent disease-modifying drugs and biologic agents. Patient pain and function was assessed prior to surgery and two years after surgery using the Western Ontario and McMaster Universities Arthritis Index (WOMAC). This tool measures pain, stiffness, and functional limitation.

Knee Replacement

In one study, investigators used the HSS Total Joint Replacement registry to identify 178 rheumatoid arthritis patients and 5,206 osteoarthritis patients who underwent a TKR. Patients with RA were sicker—while 72% of osteoarthritis patients had no comorbidities, only 34% of rheumatoid arthritis patients fell into this category.

Although TKR patients with RA had worse pain and function prior to surgery compared to controls, these differences disappeared after suYoanjii