Trigger finger

Trigger finger (stenosing tenosynovitis) is a painful condition that affects the tendons in the hand. As the finger or thumb is bent towards the palm, the tendon gets stuck and the finger clicks or locks.

Tendons

Tendons are white, fibrous cords that join bone to muscle. They allow the bone to move when the muscle contracts. In the hand, tendons run down the bones in the fingers and are attached to the muscles in the forearm.

The tendons are held in place on the bones by a series of ligaments (strong bands of tissue) called pulleys. These are shaped like arches over the tendon, attaching it to the bone. The pulleys form a tunnel, or sheath, on the surface of the bone, which the tendons slide through.

Trigger finger occurs when a problem with the sheath means that the tendon can no longer slide easily through it. As a result, it becomes harder to bend the affected finger or thumb. The tendon can get caught in the opening of the sheath and the finger gives a painful click, like a trigger, as it is straightened.

How common is trigger finger?

Around 2-3% of people develop trigger finger. While the cause of trigger finger is not known, certain factors may increase the likelihood of it developing. For example, it is more common in:

• females,
• people who are over 40 years of age, and
• people with certain medical conditions. 

These medical conditions include other conditions in the hand, such as Dupuytren’s contracture, and some long-term conditions, such as diabetes. Around 10% of people with diabetes develop trigger finger.

Outlook

In around 20-29% of people, trigger finger may get better without the need for treatment. For others, surgery is generally the standard treatment and can be up to 100% effective. It is a relatively minor procedure, although it will require two to four weeks off work to fully recover.

Glossary

Tendon
A tendon is a white, fibrous cord that joins bones to muscle. It allows the bone to move when the muscle contracts.

Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

Ligaments
Ligaments are the fibrous connective tissues that link two bones together at a joint.

Connective tissue
Connective tissues help provide support and structure to other tissue and organs.

Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.