Background Biologics improved Rheumatoid Arthritis (RA) treatment dramatically and we have abundant evidence on its high efficacy, especially on preventing joint destruction. However, we do not have enough evidence on its efficacy in halting progression of weight bearing joint destruction. There is a study reporting that biologics can stop joint destruction under Larsen Grade (LG) II, while joint destruction continues for LG III and IV. 1
Objectives In our experiences, we have many cases that required total knee arthroplasty (TKA) even when baseline LG was II or lower. X-ray may not be sensitive enough to detect inflammation, but Magnetic Resonance Imaging (MRI) can detect inflammation more accurately and precisely. MRI evaluation is expected to play a role in predicting prognosis early, which may possibly prevent TKA. We therefore hypothesized that the MRI findings on RA knees lower than LG II will give additional prediction on the severity of inflammation and chances of TKA.
Methods We performed retrospective analysis on RA patients with knee complaints at our institution. Inclusion criteria include patients treated on Etanercept with knee symptoms and underwent MRI evaluation before Etanercept was initiated. We analyzed the relationship between baseline MRI findings (presence of synovitis, T1 low/T2 high) and the chances of having TKA despite Etanercept treatment.
Results We identified total 116 RA patients on Etanercept, and TKA was performed in total 35 knee joints of 28 patients among them. TKA was performed in 12.3% of the patients in LG 0-II, and 45.5% in LG III, IV, which showed statistically significant difference (p<0.001). Those knee joints in LG0-II with MRI findings suggesting synovitis underwent TKA significantly more often than those without MRI findings (16.4%, 4.9%, p=0.0496). Similarly, baseline LG0-II joints with and without T1 low, T2 high signals showed statistical difference in the frequency of TKA (34.5% vs 0.0%, p<0.001) (Table 1).
Conclusions Once the knee joint destruction progress to LG III and IV in RA patients with knee complaints, joint destruction continues and more often results in TKA. RA patients with knee complaints would be benefited from MRI evaluation before biologics treatment, even if the knee X-ray suggests LG0-II. If MRI suggests synovitis or T1 low, T2 high findings, the disease may progress to joint destruction. We advocate MRI is a necessary test in order to predict prognosis. We also advocate that Etanercept treatment needs to be initiated in the earliest stage possible, ideally before progression to LG II.
Seki E, et al. Clin Rheumatol 2009;28:453-460
Disclosure of Interest None Declared
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