POS0548 OPTIMAL ASSESSMENT OF THE RHEUMATOID ARTHRITIS ANKLE AND HINDFOOT: A COMPARATIVE STUDY BETWEEN CLINICAL EXAMINATION AND ULTRASONOGRAPHY
Authors: K. Maatallah, H. Boussaa, H. Riahi, H. Ferjani, M. Habechi, W. Triki, D. Ben Nessib, M. Bouaziz, D. Kaffel, W. Hamdi
Journal: Annals of the Rheumatic Diseases (2021)

Background: Foot disease is a common problem in rheumatoid arthritis (RA). Therapeutic decisions are often based on clinical examination (CE) alone, which can be adversely affected by factors such as deformity, obesity, and peripheral edema. Ultrasonography (US) has previously been shown to be more sensitive than CE for detecting synovitis and tenosynovitis in RA forefeet, but few data exist for the hindfoot and ankle. Objectives: The aim of this study was to compare CE and US for the detection of hindfoot and ankle synovitis and tenosynovitis in patients with established RA. Methods: We conducted a cross-sectional study including patients with RA (ACR/EULAR 2010). Demographic data and disease parameters were collected. CE was performed by a rheumatologist for the presence or absence of tenderness, swelling, and mobility restriction of both ankles. The following tendons were examined for tenosynovitis: tibialis anterior (TA) and posterior (TP), fibularis longus (FL), and brevis (FB) (assessed together). In a second time, US examination of the tibiotalar, talonavicular, and subtalar joints and the same tendons as CE was performed by a blinded radiologist experienced in musculoskeletal imaging using a Philips HD11 device with a high-frequency linear transducer. The presence or absence of synovitis and tenosynovitis was recorded, and the composite synovitis score (power doppler / grayscale ultrasound (PDUS)) was measured for each joint. The US score of each patient was defined by the sum of the composite scores of the joints studied (0-30). A p-value &lt;0.05 was considered significant. Results: Sixty-two feet were examined in 31 RA patients (25 women and six men) with a mean age of 54.8±10.8 years old [32-70]. The mean disease duration was 8.5±7.2 years [1-37]. Rheumatoid Factor (RF) and Anti-Citrullinated Peptides Antibodies (ACPA) were positive in 61.3% and 83.8% of cases. The mean DAS28 ESR was 3.8±1.5 [0.6-7]. Clinical examination of ankles revealed tenderness in 57.4% of cases, swelling in 38.8% of cases, and restriction in the range of motion in 11.1% of cases. TA tenosynovitis was noted in 14.8% of cases, TP tenosynovitis in 22.2% of cases, and FL and FB tenosynovitis in 31.5% of cases. US showed tibiotalar synovitis in 59.3% of cases, talonavicular synovitis in 64.8% of cases, and subtalar synovitis in 46.3% of cases. TA tenosynovitis was noted in 5.6% of cases, TP tenosynovitis in 22.2% of cases, and FB and FL tenosynovitis in 25% and 11.1% of cases respectively. An association was found between clinical tenderness and US synovitis of the tibiotalar joint (p=0.013) and the talonavicular joint (p=0.027). No association was noted between clinical swelling and US synovitis in these joints. No association was noted between clinical and US tenosynovitis of TA (p=0.279), TP (p=0.436), FB (p=0.495) and FL (p=0.315). Conclusion: Clinical examination of RA ankles may be challenging and needs to be coupled with US, which is more sensitive and accurate in the detection of synovitis and tenosynovitis. Disclosure of Interests: None declared