The thickness of the A2 pulley and the flexor tendon are related to the severity of trigger finger: results of a prospective study using high-resolution ultrasonography.

We aimed to investigate the relationship between the pulley-tendon complexes and the severity of trigger finger. The thickness of the A1 and A2 pulleys, and the cross-sectional area of the flexor tendon under the pulleys, were prospectively assessed using 17 MHz high-resolution ultrasonography, in 20 patients with trigger finger (31 fingers). A control group comprised 15 asymptomatic fingers. The thickness of the A1 pulley and the proximal part of the A2 pulley, and the cross-sectional area of the flexor tendon under the A2 pulley, were significantly increased in the patient group. Clinical grade was significantly correlated with the thickness of the A1 pulley, the thickness of the proximal part of the A2 pulley, and the cross-sectional area of the flexor tendon under the proximal part of the A2 pulley. This study confirmed that the thickness of the A2 pulley and flexor tendon under the A2 pulley seems to be related to the severity of trigger finger. LEVEL OF EVIDENCES: Level III.