What is a trigger finger or trigger thumb?

Trigger finger or thumb is a condition in which a finger or thumb clicks or locks on straightening it out from bent, often painfully.

• What causes triggering?

The tendons on the palm side of the finger and thumbs run in tight tunnels on the bones.  A trigger happens when the edge of the tunnel in the palm catches on the tendon as the finger straightens.  This part of the tendon then swells causing pain and more catching.  Triggering is more common in people with diabetes but most cases occur in people without diabetes.

• Symptoms of triggering

In the early stages there may only be some clicking as the finger straightens.  This can progress to locking, where the finger sticks in the palm.  It may be possible to overcome this or pull it out using the other hand.  This is often painful.  Severe trigger fingers can get completely stuck risking permanent stiffness.

There may a lump in the palm at the base of the finger where the tendon is swollen.

• Treatment of trigger finger and thumb

Steroid injection is an effective treatment and relieves pain and triggering in around 7 of 10 cases.  As it works by reducing swelling it can take a few days to several weeks to work.  If it is unsuccessful or wears off then a second injection can be tried although the chances of success are lower.

Surgery is also generally effective for trigger finger and can be useful if steroid injections don’t work.  It can be done under local anaesthetic.  A small cut is made over the swelling in the palm and the edge of the tunnel that catches is released.  An advantage of local anaesthetic is that you can then move your finger allowing the surgeon to check the trigger has definitely gone.  Recurrence is unlikely.