Trigger thumb is a condition whereas the thumb (or other finger) painfully locks in a bent position and can sometimes be returned to its normal state under pressure with a "snap." It can be extremely painful, and can have numerous causes.
Causes
Trigger thumb occurs when the sheath encompassing the flexor pollicis longus tendon in the hand constricts and thickens, creating a tender nodule. When the tendon passes through the sheath, it has to force itself past the nodule, creating a large amount of localized resistance. In extreme cases, the nodule is large enough to cause the finger to "lock" in place once the tendon has passed through the sheath (as the finger is bent), and can only be returned to an extended form if pulled hard enough to snap back into place, forcing the tendon past the nodule into an extended position.
The cause of the swelling can vary depending on the patient. It is four times more likely to occur in women than men, and usually affects them in their 50s and 60s. People with inflammatory diseases like gout and arthritis, or those afflicted by a chronic infection are more likely than others to experience trigger thumb/finger. The swelling that causes trigger thumb/finger is usually itself caused by some manner of repetitive stress injury, usually one that involves gripping, such as holding power tools or gripping a steering wheel for prolonged periods. In some cases, a congenital defect causes trigger finger to occur in infants ages 1 to 4, although it is usually not accompanied by pain, and doesn't generally occur until infants are actively using their hands.
Symptoms
Patients with trigger finger typically exhibit a painful clicking in the affected finger, or a "popping" sensation in the affected joint. Pain is generally experienced when the finger is either extended or bent. This is usually accompanied by a tender spot at the base of the affected digits at the site of the nodule. In more severe cases, the above symptoms are accompanied by a finger that "locks" in place, which can often be straightened with a sharp snap.
Treatment
Trigger thumb/finger is a condition with few treatment options short of surgery. Cortisone shots can be used to reduce the swelling to stop the triggering, but as with most cortisone treatments, the results don't last long enough for consistent relief. Generally, surgery is the only option for long-term treatment of trigger thumb/finger, and can usually be performed in an outpatient basis. It generally involves simply dividing the tendon pulley and stitching the hand up, and is often done with a local instead of general anesthetic.
Prognosis
With nonsurgical treatments, such as a cortisone shot, effects of the treatment last for a very limited time and will almost certainly need to be repeated. For those who undergo surgical treatment, all that is necessary is bandaging of the incision until the stitches are removed, and basic care. Sometimes, therapy is prescribed for up to six weeks to improve dexterity and motor function in the affected area.
Complications
If the digit has been locked in position for an extended period of time, additional therapy may be required to stretch the tendon back to its original length in order to allow the thumb or finger to fully extend without pain or issue.
Tags: thumb finger, trigger thumb finger, causes trigger, finger usually, more likely, past nodule