Background/Purpose: Though rheumatoid arthritis (RA) commonly affects ankle joints, ankle joints are not included in widely used composite measures of disease activity with 28-joint counts. Furthermore, precise clinical examination (CE) is difficult because of its complex anatomical structure. Aim of this study is to clarify the utility of ultrasonographic assessment (US) for evaluating ankle joints by means of comparison to CE in daily clinical practice for RA.

Methods: Sixty RA patients (female 85.0%, age 60.9 ± 15.2 y.o., disease duration 6.92 ± 8.02 years, DAS28-ESR 3.93 ± 1.63) were included. US, CE and patient’s visual analog scale for pain (pVAS) of each bilateral ankle were assessed. Bilateral tibiotalar joints and three tendon sites (anterior sites; tibialis anterior, extensor hallucis longi, extensor digitorum longi, medial sites; tibialisposterior, flexor digitorum longi, flexor hallucis longi, lateral sites; peroneus longi and brevis) were assessed by gray scale (GS) and power Doppler (PD) US. Intra-articular synovitis(synovitis) and tenosynovitis were separately assessed using semiquantitative grade (0-3). Positive US findings were defined as GS score ≥2 and/or PD score ≥1, and positive CE findings were defined as joint swelling and/or tenderness.

Results:

A total of 120 ankles were evaluated. Positive US findings were found in 19 (15.8%) tibiotalar joints, 5 (4.2%) anterior sites, 16 (13.3%) medial sites, 13 (10.8%) lateral sites, respectively. When positive US findings were defined as a gold standard, sensitivity and specificity of positive CE findings were 0.68 and 0.81 for synovitis, respectively, and 0.76 and 0.88 for tenosynovitis, respectively. The concordance rate of CE and US were poor (κ = 0.39) for synovitis, whereas were moderate (κ = 0.58) for tenosynovitis. When we devided the cases into 4 groups based on the existence of synovitis and tenosynovitis, the group with both US-based synovitis and tenosynovitis showed the highest pVAS (Table). Positive CE findings were highly detected in the joints where US tenosynovitis was positive.

Table. pVAS and clinical examination of ankle among the groups divided according to US-based ankle involvement.

 ＊ P<0.0001     ANOVA test, ＊＊P<0.0001   Kruskal-Wallis test

Conclusion: CE and pVAS often reflect tenosynovitis rather than intra-articular synovitis. US sensitively detects RA involvement in the ankle joints, particularly intra-articular lesions, which are often missed by CE.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ultrasonographic-assessment-covers-clinical-examination-in-the-localization-of-ankle-pathology-in-rheumatoid-arthritis/