Study: Patients with pain after Total Knee Replacement are more likely to have a poor outcomes
Pain After TKR Ominous Sign (written by Biloine Young @ OTW)
Experiencing pain before knee replacement surgery can be a trial, but being in pain following the surgery can be a disaster. Dr. Jeffrey N. Katz, professor of medicine and orthopedic surgery at Harvard Medical School, has found that patients who experience severe pain in the first three months after total knee replacement have worse pain and less successful outcomes after one to two years. And they are less satisfied with their procedure than are other patients.
Because of that, severe pain after the operation “is something that we ought to be intervening on,” said Katz.
Depressed, catastrophizing patients and those in severe pain before the operation are all at risk for severe pain afterward, Katz, the lead investigator of a study, told an audience at the 2011 World Congress on Osteoarthritis. Using cognitive-behavioral therapy and optimizing antidepressant dosages and pain control can help, both before and after the operation, he said. Katz also suggested that “people might consider operating sooner,” before pain becomes severe.
Of the approximately 600,000 total knee replacements in the United States every year, about 15% of patients have severe pain after the operation. Until now, it wasn’t known “whether that portends poor outcomes over time,” he said.
His team found that it did, at least in the 622 unilateral, primary, total knee replacement patients in their study. Overall, 62% were aged older than 65 years, 58% were women, 35% had a body mass index greater than 30 kg/m2; and about half had two or more comorbidities.
The patients’ mean preoperative function score on the WOMAC (Western Ontario and McMaster Universities) osteoarthritis index was 47, and their mean preoperative WOMAC pain score was 41 (with 100 being the best score on the WOMAC index and 0 the worst possible).
Following the surgery, 15% of the patients had WOMAC pain scores lower than 50 at three months, which indicated severe pain. The patients with severe pain at three months had mean WOMAC function scores of about 60 at both the one- and two-year follow-up. The 85% of patients without severe pain had function scores in the mid-70s at both points.
Similarly, the severe pain group had WOMAC pain scores in the mid-60s at both one and two years. The other patients had mean WOMAC scores in the mid-80s at both points.
About 60% in the severe pain group said they couldn’t walk five blocks at both one and two years. Among those without severe pain, about 40% said that they could not walk five blocks at both points.
The patients came from 12 referral centers in the United States, the United Kingdom, and Australia. The study did not capture the reasons for the pain, the problems with implants (if any), or the patients’ psychiatric histories.