Ultrasound effectively identified joint and tendon inflammatory involvement at the ankle level in patients with rheumatoid arthritis (RA), which explains the reason for ankle pain when present, according to cross-sectional study results published in Clinical Rheumatology.

The investigators sought to describe and compare the prevalence and distribution of clinical and ultrasound pathologic findings at the ankle level in patients with RA. Patients in the study were recruited consecutively and independently of disease status or treatment, as well as regardless of the presence of pain at the ankle level. An experienced rheumatologist recorded the presence of spontaneous pain and performed a physical examination of both ankles to elicit tenderness. Another rheumatologist who was experienced in musculoskeletal ultrasound carried out a bilateral ultrasound examination of the ankles.

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Clinical evaluation was performed to detect the presence or absence of spontaneous pain and tenderness at 4 different ankle locations (anterior, lateral, medial, and posterior). Ankle movements were evaluated with the knee flexed. Ultrasound assessments were performed based on the European League Against Rheumatism and Outcome Measures in Rheumatology indications.

A total of 224 ankles in 112 patients with RA were examined; 89.3% were women. Mean participant age was 51 years and the mean duration of RA was 72 months.

Spontaneous ankle pain was observed in 56.2% of patients. Moreover, in 62.5% of participants ultrasound detected ≥1 pathologic sign that was indicative of joint or tendon pathology. With the use of grayscale ultrasound, joint involvement was reported more frequently than tendon pathology (37.5% vs 22.3%, respectively). In contrast, there was no considerable difference observed between the prevalence of power Doppler signal at the joint and tendon levels.

A significant correlation was reported between clinical findings (spontaneous pain referred by the patient and tenderness elicited during physical examination at the lateral side of the ankle) and ultrasound findings indicative of tibiotalar joint synovitis and peroneal tenosynovitis (P <.0001). No significant correlations were demonstrated between pain and tenderness, and no additional associations were reported.

A major limitation of the study is the fact that it was conducted at a single center. Moreover, 2 ultrasound systems were used, and the 28-joint Disease Activity Score was not systematically recorded in all patients.

The investigators concluded that the utilization of ultrasound in patients with RA who have ankle pain allows for sensitive detection and exact identification of joint or tendon inflammatory involvement, thus explaining the reason for the ankle pain when present and revealing the existence of subclinical disease in  patients with asymptomatic ankles.

Reference

Hernández-Díaz C, Sánchez-Bringas G, Ventura-Ríos L, Robles-San Román M, Filippucci E. Ankle pain in rheumatoid arthritis: comparison of clinical and sonographic findings [published online April 2, 2019]. Clin Rheumatol. doi:10.1007/s10067-019-04532-2