Trigger finger, trigger thumb, or trigger digit, is a common disorder of later adulthood characterized by catching, snapping or locking of the involved finger flexor tendon, associated with dysfunction and pain. A disparity in size between the flexor tendon and the surrounding retinacular pulley system, most commonly at the level of the first annular pulley, results in difficulty flexing or extending the finger and the “triggering” phenomenon. The label of trigger finger is used because when the finger unlocks, it pops back suddenly, as if releasing a trigger on a gun.
Diagnosis is made almost exclusively by history and physical examination alone. More than one finger may be affected at a time, though it usually affects the thumb, middle, or ring finger. The triggering is usually more pronounced in the morning, or while gripping an object firmly.
Typical treatment is gentle mobilization/manipulation to the joint, accompanied by laser therapy and/or interferential current and heat. Therapeutic exercises are also indicated once the condition has decreased in severity. Treatment typically takes longer for this condition because it is very common that fibrosis (scar tissue) will also be present.