Synovial involvement assessed by power Doppler ultra-sonography in systemic sclerosis: results of a cross-sectional study.

Objectives: To characterize hand synovial manifestations assessed by power Doppler ultrasonography (PDUS) in a cohort of unselected patients fulfilling the 2013 ACR/EULAR classification criteria for SSc and to evaluate the associations of these synovial manifestations with the main general clinical and biological features of SSc.

Methods: One hundred and three SSc patients were consecutively included and underwent PDUS evaluation of both hands assessing synovial and tenosynovial manifestations according to the OMERACT definitions. Clinical, biological and immunological SSc characteristics were recorded at the same time.

Results: Thirty-three patients (32%) had ultrasonographic synovial/tenosynovial involvement. The two main PDUS features were Doppler-positive/inflammatory synovitis (n = 18, 17.5%) and sclerosing tenosynovitis (TS) (n = 19, 18.4%). Inflammatory synovitis was more frequent in the wrist and MCP joints. Sclerosing TS was more frequent in men [odds ratio (OR) = 6.32, 95% CI: 2.17, 18.41; P = 0.001] and was associated with anti-RNA polymerase III antibodies (OR = 10.93, 95% CI: 1.84, 65.12; P = 0.01), diffuse SSc (OR = 18.24, 95% CI: 4.80, 69.32; P < 0.0001), interstitial lung disease (OR = 6.09, 95% CI: 1.86, 19.98; P = 0.001) and inflammatory arthralgia (OR = 14.64, 95% CI: 2.58, 83.10; P = 0.002). Inflammatory TS or synovitis were associated with CRP levels >5 mg/l (OR = 5.50, 95% CI: 1.81, 16.70; P = 0.001), pericarditis (OR = 7.81, 95% CI: 1.58, 38.71; P = 0.017) and inflammatory arthralgia (OR = 15.96, 95% CI: 2.80, 91.02; P = 0.002). Inflammatory synovitis and sclerosing TS were not significantly associated within an individual patient (OR = 2.77, 95% CI: 0.88, 8.70; P > 0.05).

Conclusions: Ultrasonographic synovial involvement is frequent in patients fulfilling the 2013 ACR/EULAR classification criteria and PDUS may have a part to play in a more accurate and precise description of musculoskeletal manifestations of the disease, especially as the question of a treat-to-target approach is arising for SSc.