Objective To evaluate the prevalence of joint inflammatory abnormalities and erosions detected by grey-scale and Doppler ultrasound (US) in the small joints of hands and feet in healthy subjects.

Methods US of the dorsal surface of 32 joints (10 metacarpophalangeal, 10 proximal interphalangeal, 10 metatarsophalangeal (MTP) and 2 wrists) was performed in 207 healthy subjects without joint symptom. Synovial effusion (SE), synovial hypertrophy (SH) and power Doppler (PD) signal were scored using a semiquantitative grading scale (0–3) and erosion binary.

Results One-hundred and eighty-two subjects had at least one US abnormality: 52% of the subjects had SE alone, 13% SH alone (5% with and 8% without PD) and 35% both SH and SE. US findings were detected in 9% of the total joints examined, mostly in the feet, and in particular in the MTP1 (33% of the positive joints). SE was the most frequently detected finding (68% of the positive joints), followed by SH (31%). Severity was mild (grade 1 in average) whatever the finding recorded (SH, SE or PD). Four erosions were detected (MTP1).

Conclusions This study describes for the first time, in a large cohort of healthy subjects, the prevalence and location of US signs of joint inflammation and of structural damage in small joints of hands and feet. US abnormalities were quite common, and mostly located in the feet. Further studies are needed to define which US components may allow to discriminate between pathological and physiological findings in the joints commonly affected by inflammatory arthritis conditions.