Trigger Finger
Stenosing tenosynovitis of the flexor tendon at the A1 pulley, producing catching, locking, and pain with finger flexion.
Overview
Trigger finger (stenosing flexor tenosynovitis) arises from a size mismatch between the flexor tendon and the A1 pulley, often with nodular thickening of the tendon. Repetitive grasping and metabolic conditions, particularly diabetes, are strongly associated. Any digit can be affected; the thumb, ring, and middle fingers are most commonly involved.
Epidemiology
Lifetime prevalence is 2 to 3 percent in the general population and 10 to 20 percent in people with diabetes. Peak incidence is in the fifth and sixth decades with a strong female predominance. Multiple digit involvement is common in diabetic and rheumatoid patients.
Symptoms
Pain and catching at the A1 pulley, progressive clicking or locking in flexion, and in severe cases a finger locked in flexion requiring passive extension. A palpable nodule is often present at the base of the affected digit.
Imaging
Trigger finger is a clinical diagnosis. Ultrasound may demonstrate A1 pulley thickening and tendon nodules and is useful when diagnosis is uncertain or for guided injection.