Trigger finger Stenosing tenosynovitis / trigger thumb

Trigger finger is a condition where it is difficult to extend the finger and the finger then unlocks with a snap. It is caused by localized thickening of the tendon that slides through a narrow tunnel in the hand.

If the thumb is affected, we call this trigger thumb.

The tendons that flex the fingers are located on the front of the hand. They run through small tunnels called "pulleys". The pulleys ensure that the tendon remains in position and that forces are passed on.

If localized thickening (a lump) forms in the flexor tendon, then this lump may not fit inside the tunnel. This causes the finger to "lock", particularly when extending the finger. In such situations, the flexor tendon is pulled toward the finger tips like a rope, meaning that the lump has to pass through the tunnel. There is some initial resistance and then it passes through the tunnel suddenly.

The problem is almost always in the tunnel that is located just below the base of the finger. However, the patient feels as if the symptoms are caused higher up, because the tendon moves the finger joints located higher up.

Trigger finger is more common in women. It is more common in the 40 to 70 age category and in children under the age of 6.

The symptoms usually start with an annoying or painful sensation just below the base of the finger. Next, the normal smooth movement of the flexor tendon is inhibited when the person bends or stretches the finger. The thickened tendon that is pulled through the pulley causes pain and results in the typical trigger finger effect.

The area also becomes more inflamed, because the tendon becomes trapped in the pulley. This in turn causes further swelling, making it even more difficult for the tendon to move through the pulley. Resulting in a vicious circle.

Usually, the diagnosis is quite straightforward to make, as this condition shows very characteristic symptoms. After an interview and a physical examination of the hand, it is usually quickly clear whether it is a trigger finger. The healthcare professional palpates the place where the tendon catches and asks you to actively bend and extend the finger. Further tests are not necessary.

If the symptoms developed very recently, a wait-and-see approach should be implemented first. If no improvement occurs, you could consider administering a corticosteroid injection (anti-inflammatories). This yields improvement in most cases. If this does not provide relief either, the pulley can be cut through surgically so that the tendon can move smoothly again.

Peters-Veluthamaningal, C., Willems, W., Smeets, J.G.E., Windt, D.A.W.M. Van der, Spies, M.N., Strackee, S.D., Vos, K., Wind, L.A. & Geraets, J.J.X.R. (2010) NHG-Standaard. Hand- en polsklachten Huisarts Wet. 2010:53(1):22-39.
Verhaar, J.A.N. & Linden, A.J. van der (2005) Orthopedie Houten: Bohn Stafleu van Loghum.