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It's occupations and activities that involve repetitive gripping actions such as gardening, or playing musical instruments that make trigger finger more likely to occur.

Mild symptoms may only need the hand to be rested and for repetitive overuse of the finger to be avoided for the problem to be overcome. In more serious cases, anti-inflammatory drugs or a steroid injection into the affected tendon to decrease swelling and restore normal tendon function often solves the problem. When these measures aren't successful, however, day case surgery to remove the problematic tissue, often followed by a course of hand therapy, will be recommended

Trigger finger

Dr Rob Hicks

You don't have to go near a gun to develop trigger finger. It's occupations and activities that involve repetitive gripping actions such as gardening, or playing musical instruments that make trigger finger more likely to occur.


What it is

Medically termed as stenosing tenosynovitis, trigger finger is a common problem that interferes with the normal functioning of the fingers or thumbs. For some it's just a nuisance, whereas for others it can be painful.

Its name doesn't come from the finger that's affected since any finger may be affected by this condition. The name trigger finger originates from the process of trying to bend and straighten the affected finger or thumb, which then gets stuck in a bent or flexed position as if ready to pull a trigger, and only when enough force is produced does the affected digit suddenly straighten or extend.

If you make a fist and then relax it again allowing your fingers and thumb to straighten you'll feel how the movement of your digits is smooth and continuous. Bending and straightening fingers and thumbs in this way involves pulleys and tendons in the hand. The tendons are like long ropes that connect muscles of the forearm with the bones of the fingers and thumb. When the muscle contracts these tendons pull the digits into a fist. Part of the course that the tendons follow is through a sheath or tunnel that, like the tendons, has a smooth lining. This allows the tendon to glide easily to and fro. When trigger finger occurs, this ease of movement is inhibited.

What happens

Trigger finger arises when a nodule, or knot, develops in one of these tendons. Inflammation or scaring is believed to be responsible for this, usually due to repetitive overuse of the tendons as occurs in repeated gripping actions, or inflammatory medical conditions such as rheumatoid arthritis.

It's more likely to arise in those people who have medical conditions such as gout and diabetes. Sometimes there's no reason to explain why a nodule has developed.

Imagine passing a piece of string through some piping and then tying a knot in one end of the string. As you pull the string back through the piping once the knot reaches the entrance to the piping, if the knot is larger than the diameter of the piping, the passage of the string becomes obstructed. Pull hard enough though and the knot may suddenly enter the piping and may even pass through it.

This is similar to what happens in trigger finger when the nodule reaches the tunnel. The problem arises because the size of the nodule makes it difficult for it to pass into the entrance to the tunnel. Overcoming this resistance results in a snapping of the trigger finger when straightening the finger or thumb. If the condition worsens, the trigger finger may need to be forcibly straightened, or may not straighten at all and remain locked in a bent position.

Treatment

Despite appearing to be a problem of the joints within the finger, the problem is at the finger joint nearest the hand. When trigger finger has developed, a bump may be felt at this part of the hand when it's examined.

To overcome the problem of trigger finger, any obstruction to normal tendon movement needs to be removed. Specific treatment used to achieve this depends upon how severe the symptoms are and how trigger finger is affecting an individual.

Mild symptoms may only need the hand to be rested and for repetitive overuse of the finger to be avoided for the problem to be overcome. In more serious cases, anti-inflammatory drugs or a steroid injection into the affected tendon to decrease swelling and restore normal tendon function often solves the problem. When these measures aren't successful, however, day case surgery to remove the problematic tissue, often followed by a course of hand therapy, will be recommended.

This article was last medically reviewed by Dr Rob Hicks in December 2005

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