Arthritis Today—July 5, 2013
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.
Dr. Goodman says the study doesn’t explain why there are differences between the OA and RA patients getting hip replacements. She speculates that RA hip replacement patients may be putting off the surgery too long (as evidenced by their poor pre-operative function).
Dr. Goodman points to another interesting factor: Researchers found that patients who expected that they would do well with surgery were in fact more likely to do well and less likely to report bad pain and function scores.
“Having poor function was less of a predictor of your outcome than feeling like you can do well, which I think is fascinating,” Dr. Goodman explains. “The message there is we really need to talk to our patients about what they can expect from a single joint [replacement]. I think patients who go into this with a good attitude and patients who have spoken to their doctors and have a good plan for their rehabilitation and keep their RA under good control – they probably will do as well as OA patients.”
Dr. Goodman says the bottom line for RA patients is that joint replacements are an important and effective surgery.
“We have no evidence RA patients have more adverse events. They do improve significantly and they are very satisfied with the outcomes – they just aren’t hitting the mark the OA patients are,” Dr. Goodman says. “Absolutely get the knees done when you meet the criteria and watch the hips carefully. It may be you are waiting too long. The timing of the surgery might be a place to look when it comes to what we can do differently.”
Read the full story at arthritistoday.com.