Trigger finger is a condition in which one or more of your fingers may be difficult to bend or gets stuck in a bent position. The condition it is also known as stenosing tenosynovitis. It occurs when the flexor tendon can no longer slide easily under the A1 pulley at the base of the finger causing pain and locking.

What are the causes of trigger finger?

The flexor tendons are long cord-like structures that attach the muscles of the forearm to the bones of the fingers. When the muscles contract, the flexor tendons allow the fingers to bend. 
Trigger finger is caused by inflammation of the tendon sheath (tenosynovium) that covers the tendons. Along the tendon sheath, bands of tissue called “pulleys” hold the flexor tendons on the bone and prevent bowing. In trigger finger the A1 pulley at the base of the finger becomes inflamed and thickened making the gliding of the tendon difficult. The tendon may develop a nodule that clicks when it goes under the pulley. 

What are the symptoms?

In early stages difficulty in moving the affected finger is the only symptom. As the nodule forms a pop or a click can be heard when the finger unlocks and the nodule slides under the pulley. The area over the A1 pulley is tender to palpation. Occasionally the finger can get stuck in a bent position which makes everyday activities difficult.

What is the treatment for a trigger finger?

Treatment options for a trigger finger include analgesia, wearing a plastic splint, cortisone injections and surgery. If you have a trigger finger you should avoid activities that require repetitive gripping or grasping or use of vibrating hand-held machines until your symptoms improve. A splint that keeps the finger in extension may bring some relief too.
The most common treatment option is a steroid injection around the A1 pulley. This may improve symptoms permanently but occasionally the symptoms come back. A second injection is not recommended. 

What about surgery?

If your symptoms persist despite conservative treatment and you already had a steroid injection that relieved your symptoms temporarily you may be a candidate for surgical release of the A1 pulley.
The procedure is done under local anaesthetic as a day case. You will feel the improvement immediately.

Are the symptoms worst in the morning? YES. The triggering of the affected finger is worse in the morning when you initially start moving your fingers. In early stages the clicking goes away during the day.

What happens if the trigger finger is left untreated? Left untreated the finger may become permanently stuck in a bent position or rarely in a straightened position.