According to a new study, total knee arthroplasty is highly effective in reducing clinically relevant knee pain to a greater extent than other subjective health-related quality-of-life indicies in patients with rheumatoid arthritis, although this improvement is less marked as compared to outcomes in patients with osteoarthritis. These study findings were published online ahead of print July 20 in Arthritis & Rheumatology.
The study included patients with rheumatologist-diagnosed arthritis undergoing primary total knee arthroplasty during 1999 to 2012. Indices of pain knee, and health-related quality of life were obtained in 3 consecutive 6-month intervals: preoperative, perioperative, and postoperative. Descriptive statistics and 1-way analysis of variance were used to compare total knee arthroplasty outcomes by diagnosis. Effect sizes and standardized response means were calculated between baseline and recovery.
Kaleb D. Michaud, PhD
Of the participating 18,897 patients, 834 people with rheumatoid arthritis, and 315 people with osteoarthritis had undergone index total knee arthroplasty at mean ages 65 and 68. Post total knee arthroplasty, significant improvements were observed for most domains of pain, function, and health-related quality of life within both disease groups, with greater impact in osteoarthritis. Based on the standardized response means, the maximum improvement was shown in index knee pain.
The Health Assessment Questionnaire II and the Short Form 36 physical component summary were the most responsive health-related quality of life indices in detecting post-total knee arthroplasty improvement in rheumatoid arthritis. A diagnosis of rheumatoid arthritis, lower income, and preoperative anxiety were independently associated with a lower degree of improvement in index knee pain following total knee arthroplasty.
Senior author Kaleb D. Michaud, PhD, Associate Professor in the Division of Rheumatology and Immunology at the University of Nebraska Medical Center in Omaha, and colleagues said that total knee replacement can serve as a “time machine” by which patients can return to a less disabled lifestyle, before the arthritic process catches up.
“A new knee can give osteoarthritis patients 10 to 20 years of painless use, whereas rheumatoid arthritis continues to affect the joint soon afterward,” the researchers said. “It’s an important and effective treatment, but patients with rheumatoid arthritis shouldn’t expect the same, often dramatic results experienced by their osteoarthritis counterparts,” Dr. Michaud said.