Comparison of Ultrasonographic Features Among Healthy Individuals and Patients With Trigger Finger

The trigger finger is one of the leading causes of finger pain and triggering. The flexor tendons are stabilized by a fibrous band called the annular pulley. The first annular pulley (A1 pulley) is located at the level of the metacarpophalangeal joint. Trigger finger is characterized by thickening of the A1 pulley. There is a lack of clinical and ultrasonographic risk factors that may help clinicians. The main purpose of the study was to measure the thickness of the flexor tendon and A1 pulley in patients with trigger finger compared to healthy volunteers and to reveal risk factors of trigger finger.

The study included 30 healthy volunteers and 30 patients with trigger fingers. The thickness of the flexor tendon and A1 pulley were measured using ultrasound. Multiple regression analysis was also conducted.

In the healthy group, the mean thickness of the flexor tendon and A1 pulley were 3.21 ± 0.64 and 0.40 ± 0.09 mm, respectively. In the TF group, the mean thickness of the flexor tendon and A1 pulley were 3.78 ± 0.86 and 0.49 ± 0.16 mm, respectively. The differences were statistically significant (p = 0.010 and p = 0.009, respectively). The mean thickness of the flexor tendon and A1 pulley of trigger finger were significantly higher than adjacent and contralateral healthy digits of the patients with trigger finger (p = 0.001, p = 0.001, p = 0.019, p = 0.002, respectively). The risk of trigger finger was found to be 11.5 times higher in diabetic patients, 3.734 times higher in patients with a history of hand forcing, 2.912 times with a 1 mm increase in flexor tendon thickness, and 1.724 times with an increase of 0.1 mm in A1 pulley thickness.

In this study, the flexor tendon and A1 pulley were found to be more thickened in the trigger finger group compared to the controls. Diabetes mellitus, history of hand forcing, increased tendon, and A1 pulley thickness are among the risk factors associated with trigger finger.

Ultrasound Features of Trigger Finger, Registry number: NCT05675488.