Rheumatoid Arthritis Patients Have Low Expectations After Knee Replacement Surgery

Compared with osteoarthritis patients, individuals with rheumatoid arthritis who undergo total knee replacement surgery have lower expectations about their postsurgical outcomes, according to a new study by researchers at Hospital for Special Surgery (HSS) in New York City. These reduced expectations, which may be unnecessary, could cause some patients to slack on their postsurgical rehabilitation leading to worse outcomes, say doctors. The study will be presented November 7 at the annual meeting of the American College of Rheumatology.

“If rheumatoid arthritis patients are healthy enough to have surgery, they should really expect good outcomes. If patients have lower expectations, then maybe they don’t push their physical therapy, and perhaps don’t recover as well,” said Lisa Mandl, M.D. M.P.H., a rheumatologist at HSS who was involved with the study. “It would be a real shame if these patients could have significantly improved function, but for some reason they don’t attain it, perhaps connected to their expectations.”

Before this study, researchers had known that patients with rheumatoid arthritis (RA) who undergo a total knee replacement are often very satisfied with the surgery, even though they have inferior outcomes to patients with osteoarthritis who undergo the operation. Because satisfaction is determined not only by improvements in pain and function, but by fulfillment of pre-operative expectations, investigators set out to determine if the expectations of the two patient groups differed.

The researchers turned to the HSS Total Joint Replacement Registry, a prospective registry started in 2007 that includes, among other things, data on all patients who seek care at HSS for knee replacement surgery, also known as total knee arthroplasty (TKA). Because roughly 90 percent of patients who undergo TKA have osteoarthritis, they first used the registry to identify patients with RA. They then mined the registry to find osteoarthritis patients that matched these RA patients in terms of age, gender and function. Investigators gauged function using the Lower Extremity Activity Score (LEAS), a score that quantifies how much activity a person is capable of performing. The scale ranges from a person being confined to bed all day to participating in vigorous physical activity such as competitive level sports.

The researchers identified 62 RA patients and matched them to 124 osteoarthritis controls; 81.7 percent were women and the average age was 64.7 years. The average LEAS was 8.7, which corresponds to being able to walk around the house and for several blocks without assistance.

The investigators measured pain, stiffness and function prior to surgery, using a tool called the Western Ontario and McMaster Universities Arthritis Index (WOMAC), and found that patients with RA had worse scores. "Even when you try to match these patients to make them similar, it really does seem like this chronic disease makes these patients sicker, less happy, less functional and clearly they have worse expectations," Dr. Mandl said.