How is trigger finger different from Dupuytren contracture?
As a reader of this website, you probably have a good idea about Dupuytren contracture, but not a clear idea of what is called a trigger finger.
Trigger finger defined
A trigger finger is a mildly to moderately painful condition in which any finger or thumb becomes suddenly stopped or blocked during finger movement while in a flexed or curled position. In severe cases, the trigger finger cannot be voluntarily straightened; in less severe cases of trigger finger the locked finger can only be straightened or unlocked with deliberate effort. The trigger finger name comes from the sudden release and snapping or popping sensation that occurs when the finger finally does straighten – much like the trigger of a gun that suddenly releases with a clicking sound.
To understand what happens when a trigger finger locks while it is flexed, it is necessary to understand a bit of hand anatomy. Those muscles that bend and straighten the fingers are not located in the hands – they are located in the forearms. These forearm muscles can operate the fingers because they are connected to the fingers by long tendons that extend to each fingertip. When these tendons pass through the palm on the way to the fingers, they are encased or covered with a fibrous sheathe (like a sword is kept in a sheath). The sheath protects the tendon, guides the tendon where it passes between bones, and keeps it lubricated to make movement smoother and easier.
A trigger finger develops when there is a narrowing or constriction in the tendon sheath and a nodule develops as a result of overuse or injury. When the finger is flexed, causing the nodule on the tendon to pass through the narrowed part of the sheath, the nodule or thickened are will catch or resist at that same point in the flexed position that brings the narrow area and the nodule together. The sudden snap release of the trigger finger occurs when the nodule or thickening suddenly passes the restricted portion and can again freely slide past it.
The cause of trigger finger is often related to a large sudden injury or small repeated injury or overuse of the hand, or as a result of a degenerative process as with aging or disease.
Most often a trigger finger will act up in the morning, or after a period of rest after heavy hand exertion. The finger will suddenly catch or lock while in the flexed or bent position and then with a little effort to straighten the finger it will suddenly straighten accompanied by a clicking sensation. A trigger finger occurs more often in the dominant use hand, since this is the one most subject to overuse and injury, and most often develops in the thumb, middle or ring finger. More than one finger can be affected at a time, as well as both hands can have a trigger finger.
Trigger finger different from Dupuytren’s contracture
Trigger finger is not the same as Dupuytren’s contracture; they are only similar in that both involve finger flexion. Dupuytren contracture is a condition in which thickening and shortening of the connective tissue occurs in the palm of the hand, that resemble cords and nodules, in which there is some finger flexion as a result. Both Dupuytren contracture and trigger finger can occur at the same time in the same hand, since the soft tissue changes of the former can favor development of the later.
In the experience of DCI working with this problem since 2002, we find that many of our Dupuytren contracture treatment ideas can help to reduce or eliminate a chronic trigger finger problem.