What is a trigger finger?
Trigger finger, also known as “stenosing tenosynovitis of the finger,” is a condition affecting the hand function of many people. Symptoms occur when there is a size mismatch between the flexor tendons of the fingers or thumb and the sheath which surrounds the tendons. Instead of gliding smoothly through the sheath, the tendons can meet resistance within the tight sheath, which can be painful. Some patients report “catching” or “clicking” of the finger with range of motion. Some people may feel a tender nodule or “bump” at the base of the finger/thumb. In advanced cases, the finger can become stuck or “locked” in flexion, requiring the person to straighten the finger with the other hand. These symptoms are often worse in the morning
What causes trigger finger?
The cause of trigger finger is unknown in most cases. Repetitive, forceful gripping or trauma may contribute to the process. Sometimes rheumatoid arthritis (RA), diabetes, gout, and thyroid disorders are associated with trigger finger. In some conditions, the tenosynovium, which is normally thin tissue surrounding the tendons, becomes thickened and obstructs tendon gliding.
Who is at risk for trigger finger?
Trigger finger is more common in females than males. It typically occurs in people between 40 and 60 years of age. Diabetics and patients with RA have a higher risk. Despite the name, trigger finger can occur in any finger, and it is common in the thumb. Children may also have a trigger finger, however, this is much less common. “Congenital trigger thumb” is occasionally diagnosed in infants who cannot fully straighten the end of the thumb.
How is trigger finger diagnosed?
Trigger finger can be diagnosed by history and physical exam. Laboratory tests, x-rays, ultrasound, and MRI are usually not necessary to confirm the diagnosis. Often a cyst or nodule arises from the tight sheath, which can be felt in the palm.