What is trigger finger?
Trigger finger, also known as stenosing tenosynovitis, is pain or stiffness when straightening or bending the finger.
Swelling of the tendon lining (a tunnel in which the tendons glide to bring about motion) lessens the gliding motion of the tendons, causing finger joint pain or a 'catching' feeling when you try to flex your finger. This condition may also cause the finger to become locked or stuck in a bent position.
Also called trigger thumb, trigger finger usually affects those who perform repetitive gripping movements in their line of work or hobby.
What are the symptoms of trigger finger?
The symptoms of trigger finger include:
- A nodule (swollen lump) at the base of the finger
- Finger joint pain
- Tightness at the base of the finger or stiff fingers
- Triggering or locking when opening or closing the fingers. When the finger begins to trigger or lock (stuck in a bent position), there may be pain felt in the middle of the finger or thumb
- A painful snapping or popping sensation upon bending and straightening the finger
- An aching sensation
What are the causes of trigger finger?
Tendons are a strong band of fibrous connective tissues that link the muscle to the bone. These tendons are protected by another layer of connective tissues called the tendon sheaths.
When the tendon sheaths on the finger are inflamed, the normal gliding motion of the tendon through the tendon sheath is disrupted. When the tendon sheath is irritated or inflamed for a long period, the tendons can be scarred, thickened and may develop bumps or nodules.
This can interfere with the tendons' movement, which can lead to stiffness and pain in the finger, a condition known as trigger finger.
While the causes of trigger finger are not always clear, they may include:
- Rheumatoid arthritis
- Injury to the palm or base of the finger
What are the risk factors for trigger finger?
Factors that put you at risk of developing trigger finger include:
- Occupation and hobbies. People whose occupation or hobby requires them to regularly execute repetitive and prolonged hand gripping have a higher risk of developing trigger finger.
- Gender. Trigger finger is a condition more common in women. Though it is only a theory, it is said that hormone changes in women play a role in the development of trigger finger. Changes in oestrogen levels have something to do with increased swelling in tendons and joints. This makes trigger finger more likely for women.
- Pre-existing health conditions. People with rheumatoid arthritis and diabetes are at risk of developing trigger finger. People with diabetes are at a higher risk of developing trigger finger as it is said that chronically elevated blood glucose levels can make the connective tissues glycated. This causes damage that can lead to trigger finger.