Overall satisfaction rates are high for patients with rheumatoid arthritis (RA) who had total knee replacement or total hip replacement surgery, according to two new studies presented recently at the European League Against Rheumatism (EULAR) 2013 Annual Congress. The studies also found that RA patients were as likely as osteoarthritis (OA) patients to see important improvements in pain and function after either surgery, even though some RA patients did not do as well as OA patients after hip surgery.

The findings call into question conventional wisdom, which holds that RA patients who undergo joint replacement surgery have worse outcomes than OA patients. Historically, RA patients, possibly because of their underlying disease, have not fared as well. But many of the studies were done before biologics were in widespread use.

“RA patients were just as likely to have significant improvement and on the questions of satisfaction, they were as satisfied. They were doing much better than when they went into the surgery,” explains lead author of both studies Susan M. Goodman, MD, a rheumatologist at Hospital for Special Surgery in New York City. “But the likelihood of not doing well is higher for that RA group [getting a hip replacement] even though their absolute improvements are the same. They improve and are very satisfied with it – they just aren’t doing as well as OA patients.”

The two studies analyzed data from Hospital for Special Surgery’s Total Joint Replacement Registry, which was started in 2007. Both studies assessed patients’ pain and functional abilities before surgery and two years later, as well as patient satisfaction.

In the knee study, investigators compared 178 RA patients and 5,206 OA patients who had total knee replacements (TKR). RA patients had much worse pain and function before the surgery, but after the procedure they had similar outcomes and satisfaction rates as the OA patients.

The knee study also looked at patients who had revision knee replacement surgery (a second procedure on the same knee). The 32 RA patients and 342 OA patients had similar pain and function before the second surgery. But two years later, RA patients were doing better than OA patients: They had less pain and better function than the OA patients and a higher percentage of them (90 percent) were satisfied with the outcome compared to the OA patients (67 percent).

The same high level of improvement was not found when researchers compared RA and OA patients undergoing hip replacements. Among 202 RA patients and 5,810 OA patients having hip replacements, the RA patients had worse function and higher pain before surgery. Two years later, even though nearly all patients in both groups had a significant 10-point improvement in their function scores, 18 percent of RA patients still had poor function compared to only 4 percent of OA patients.

Similarly, 92 percent of RA patients (compared to 96 percent of OA patients) had significant 10-point improvements in their pain scores, yet 12 percent of RA patients still had poor pain scores compared to only 3 percent of OA patients. A significantly higher percentage of OA patients (96 percent) were very or somewhat satisfied compared to RA patients (89 percent).

Results were similar among RA patients who had revision hip replacements: The absolute outcomes were not as good as OA patients, even though they had significant improvements in pain and function.