What is trigger finger?

Why would your finger get stuck in a bent position? Trigger finger (and trigger thumb) is a real condition affecting the tendons in the hand, which can lead to a rapid decline in the ability to grip and perform basic tasks. Expert orthopaedic surgeon Mr James Nicholl is here to explain.

What is trigger finger?

Trigger finger or trigger thumb is a fairly common wear-and-tear condition, which results in the digit locking in a bent position. It can be difficult to straighten again, with the patient often experiencing pain and a clicking sensation and/or sound.

Patients with diabetes and rheumatoid arthritis seem to be more prone to developing trigger finger.

How trigger finger happens

Trigger finger occurs due to wear and tear of the tendon that controls the digit. The tendon in the affected finger snags in the sheath (tube in which it is supposed to glide). This snagging happens at the mouth of the tube, which is situated just at the crease of the palm.

The tendon starts to tear slightly at the point where it snags, almost like a frayed rope, and a nodule develops. The collar at the end of this tube also becomes thickened and inflamed, creating a tight ring for the slightly degenerate tendon with a lump on it to pass through.

Trigger finger is usually worse first thing in the morning. This is because during sleep, we don’t flex our fingers very much. Moving the fingers is what disperses the natural lubricant – synovial fluid – in the tube; without this fluid, the finger is more liable to seize up.

Worsening with time

Trigger finger is a progressive problem. Patients often try to avoid bending the finger as much as possible, as gripping can cause the finger to get stuck. However, this leads to a decline in hand function, making day-to-day tasks like getting dressed and driving very difficult.

• In the early stages, it is simply a clicking sensation that can be overcome by moving the finger
• In the second stage, patients might only be able to straighten the digit by using their other hand to do so
• In the final stage, straightening the finger may prove impossible.

Occasionally the digit locks straight and cannot be easily bent.

Congenital trigger thumb

Sometimes, trigger thumb can occur in babies during their first year of life, due to a tendon nodule that prevents the tendon from passing into its sheath, and therefore preventing the thumb from straightening. Congenital trigger thumb is first managed by the parents gently massaging and stretching the thumb straight; if this fails, surgery may be required under general anaesthetic.

For more information or to book an appointment, visit Mr Nicholl’s Top Doctors profile.