OMAHA, NE — Total knee arthroplasty (TKA) is effective in reducing pain for patients with rheumatoid arthritis (RA) but not as much as with osteoarthritis (OA) patients, according to a new study.

The report, published recently in the journal Arthritis & Rheumatology, identified patients with rheumatologist-diagnosed arthritis undergoing primary TKA during 1999-2012.

Researchers from the VA Nebraska-Western Iowa Health Care System and University of Nebraska Medical Center, both in Omaha, obtained indications of pain — overall, index knee, and contralateral knee — and health-related quality of life (HRQOL) in three consecutive six-month intervals: preoperative (baseline), perioperative, and postoperative (recovery) for 18,897 patients.

Of those, 834 with RA (5.3%) and 315 with OA (10.2%) had undergone index TKA at similar mean ages, 65 and 68 years. After surgery, significant improvement was observed in pain, function and HRQOL for both groups, although the impact was greater in those with osteoarthritis than rheumatoid arthritis. The greatest effect was relief of knee pain, according to the study.

Study authors report that the Health Assessment Questionnaire II and the Short Form 36 physical component summary were the most responsive HRQOL indices in detecting post-TKA improvement in RA. A lower degree of improvement in index knee pain after knee arthroplasty was associated with a diagnosis of RA, lower income and preoperative anxiety, according to the results.

“TKA is highly effective in reducing clinically relevant knee pain (to a greater extent than its effect on other subjective HRQOL indices in patients with RA), although this improvement is less marked as compared to that among patients with OA,” the authors conclude. “TKA serves as a ‘time machine’ via which patients can return to a lifestyle with less disability, before the arthritis process catches up in RA.”

1 Dusad, A., Pedro, S., Mikuls, T. R., Hartman, C. W., Garvin, K. L., O’Dell, J. R. and Michaud, K. (2015), Impact of Total Knee Arthroplasty as Assessed Using Patient-Reported Pain and Health-Related Quality of Life Indices: Rheumatoid Arthritis Versus Osteoarthritis. Arthritis & Rheumatology. 67:2503–2511. doi:10.1002/art.39221