Abstract
Introduction
The systematic effects of joint replacement in rheumatoid arthritis (RA) patients are that inflamed synovium and pathological articular cartilage has dissipated. Expectations of total knee arthroplasty (TKA) are reduction of inflammatory cytokines, decreased disease activity and improvement of drug efficacy and ADL. Remission of rheumatoid arthritis is defined as having a Disease Activity Score DAS28 (ESR) of less than 2.6 and Health Assessment Questionnaire (HAQ) – Disability Index, less than 0.5.
Purpose
We investigated whether TKA could reduce disease activity and improve ADL, and subsequent remission levels of DAS and HAQ or not.
Material and Methods
We analyzed the Knee Society Score (KSS), KOOS score and DAS28 in 15 patients, 23 rheumatoid arthritic knees at pre-operation and 1 year after operation. Preoperatively patients had used non-steroidal anti-inflammatory drugs, prednisolone, disease-modifying anti-rheumatic drugs including methotrexate. TKA (Zimmer NexGen LPS Flex Knee implants and Stemmed Tibial component with stem) was performed with the modified gap technique or modified anatomical technique using original tensor with synovectomy.
Results
Preoperative and postoperative KSS are 45.7±18.1 and 88.7±17.7 (P<0.01) respectively, and function scores were 40.1±21.7 and 74.8±24.0 (P<0.01) respectively (Figure 1). Preoperative and postoperative KOOS score (%) were ‘pain’ 50.6±37.8 and 95.4±19.3 (P<0.01), ‘symptom’ 56.6±32.8 and 94.7±18.6 (P<0.01), ‘ADL’ 60.6±27.9 and 89.5±32.4 (P<0.01), ‘QOL’ 28.4±32.1 and 63.6 ±22.9 (P<0.01) and ‘sport’ 20.56±29.52 and 47.10±33.9(P=0.06), respectively (Figure 2). Preoperative and postoperative DAS28(CRP) were 4.48±1.08 and 3.58±1.11(P<0.01), and DAS28 (ESR) were 4.90±1.02 and 4.13±0.99 (P=0.02) (Figure 3).
Discussion
Each scores except ‘sport’ and DAS28 (ESR) improved statistically 1 year after operation.
Function score, ‘ADL’ and ‘QOL’ scores also improved. HAQ score includes 2 categories related to walking ability and TKA was expected to improve the HAQ score, although the HAQ score is highly affected by upper arm function. The ‘sport’ score did not improve because almost all patients did not do sports preoperatively and postoperatively.
DAS28 (ESR) and DAS28 (CRP) correlate strongly, but in this study there were statistical discrepancies in improvement. This might be because age, sex, disease duration, and existence of rheumatoid factors, anti-cyclic citrullinated peptide antibody and DLA-DRB1 shared epitope have been shown to influence ESR.
DAS28 improved by a little less than 1.0, but there was limited control of disease activity. It was reported that the average DAS 28 didn't drop below 3.2 in 3 years follow-up after TKA.
In this study we did not assess depending on preoperative disease activity, but it was reported that TKA had a systematic effect on severe or moderate RA activity, not low disease activity.
