Background There have been some reports that total arthroplasty can improve the disease activity in RA patients. The RA disease activity is commonly assessed using composite measures. These include five components: inflammation markers, the swollen joint count, tender joint count, patient's global VAS and evaluator's global VAS. Therefore, total arthroplasty can improve all of these components if there is improvement of arthritis, even if it is only in the surgical site. It is still unclear whether the improvement of disease activity is only at the surgical site or includes other joints.

Objectives The aim of this study was to assess the arthritis of systemic large joints at baseline and 12 weeks after TKA using 18FDG-PET (PET)/CT in patients with RA.

Methods Seventeen RA patients who underwent TKA were included this study. We assessed the FDG-PET, CRP, ESR, MMP-3, DAS28-ESR, DAS28-CRP, CDAI, SDAI, HAQ-DI, HSS score and Knee ROM at baseline (just before TKA) and 12 weeks after TKA.

Results The median age of the patients was 68 years old, and the disease duration was 23 years. Concomitant MTX and PSL treatment was being administered to 71% of the patients. One patient was treated with infliximab, two used etanercept, one used tocilizmab and two used abatacept. The CRP, MMP-3, all of the composite measurements, the HAQ and the knee function improved significantly 12 weeks after TKA. These data show the changes in the SUV of each joint. The SUV of the bilateral wrist joints decreased significantly 12 weeks after TKA. However, the SUV of other large joints were unchanged.

Conclusions TKA can improve not only the ADL and knee function, but also the disease activity in RA patients. However, TKA has limited effectiveness against the arthritis of the joints not undergoing surgery.

1. Kanbe K, Inoue K.; Efficacy of arthroscopic synovectomy for the effect attenuation cases of infliximab in rheumatoid arthritis. Clin Rheumatol. 2006

Disclosure of Interest None declared