Trigger Finger

The snapping of the finger during release is comparable to the pulling and release of a trigger. This gives the condition this name. The official name for the condition is actually stenosing tenosynovitis. When it affects the thumb, it is known colloquially as “trigger thumb”

Trigger finger is caused by inflammation in the sheath that surrounds the tendon controlling the  finger. That inflammation narrows the space in the sheath and makes tendon movement difficult. When the condition is severe, it can cause the finger to be locked in the bent position. The patient then has even greater difficulty trying to straighten the finger.

Trigger finger tends to affect people who work in occupations requiring plenty of gripping movements of the wrist and fingers.

Home based treatment can include use of painkillers or nonsteroidal anti inflammatory drugs (NSAIDs). In addition, resting the affected finger, using a finger splint and special stretching exercises can help. If these fail, doctors may suggest steroid injections and other surgical procedures.

Causes Of Trigger Finger

The movement of each finger is controlled by a “flexor” tendon passing through the middle of the finger. The tendons  connect to muscles at the base of each finger.  Each tendon is encased in a protective sheath.

In a healthy finger, the tendon moves freely up and down the sheath as the finger is straightened or bent.

However, the sheath containing the tendon may become irritated and inflamed. Once this happens, there is less room for the tendon to glide through the middle of the sheath. The finger is then more difficult to bend or straighten and trigger finger develops.

If the condition is not treated, the tendon may develop scars and bumps that impede finger movement even more. These bumps are called nodules.

The irritation and inflammation of the tendon sheath usually happens in response to repetitive finger movements over an extended period. Trigger finger is therefore an example of an overuse or repetitive stress injury (RSI)

Trigger Finger Risk Factors

As with any RSI, there are a number of factors that may increase the risk of developing the condition. In the case of trigger finger, these are:

• Repeated gripping activity, perhaps due to occupational responsibilities or recreational pursuits;
• Research suggests that heath problems such as diabetes or rheumatoid arthritis  are linked to trigger finger;
• Gender- the condition is more common in women than men;
• Some people develop trigger finger in the aftermath of surgery to correct carpal tunnel syndrome.

Symptoms

Symptoms of trigger finger include the following:

• Finger stiffness and reduced range of motion, particularly just after awakening;
• Hearing or sensing a popping or clicking when finger movement is attempted;
• The base of the affected finger may feel “tender to the touch”;
• The appearance of a bump at the base of the affected finger;
• The finger may be locked for a while in a bent position and then suddenly straighten with a “pop”;

Trigger finger occurs sometimes in more than one finger and may sometimes occur in the thumb.

Diagnosis

Trigger finger diagnosis generally requires only a review of the patient’s medical history and a physical exam.

The review of medical history will be to determine whether there are any previous hand or wrist injuries that may be contributing to the problem.

As part of the physical exam the patient may be asked to open and close the hand. The doctor will check for painful areas while this is done.He or she will also check the extent of finger/thumb locking and stiffness.

Another telltale sign of trigger finger that the doctor may look for is a bump on the palm at the base of the affected finger. During movement of the fingers, the doctor will probably check for corresponding bump movement. This would indicate that the bump is actually on the tendon moving the finger – a sign of trigger finger.

Treatment

As with most RSIs, treatment of trigger finger should start with non-invasive home based methods. Surgery and/or more invasive approaches should be tried only if conservative methods fail.

Home Based

This stage of the treatment will usually include:

• Resting the injured flexor tendon by avoiding gripping or grasping activity. The patient will also be advised to avoid hand held vibrating machinery as this will also tend to engage the flexor tendon in gripping activity;

• Use of NSAIDs to relieve pain and inflammation;
• Using a finger sprint to keep the finger straight. This may be required for around 6 weeks before the symptoms ease. For trigger thumb, a thumb brace like the BioSkin Thumb Spica would be a good choice.
• Working with a physical therapist who will design a program of thumb/finger stretching exercises.

Surgical Treatments For Trigger Finger

If the above home based treatments do not bring relief, doctors may suggest progressively more invasive options:

• Injecting a steroid medication into (or near) the tendon sheath to reduce inflammation.
• Inserting a needle into the tissue around the affected tendon. The needle is then moved (together with the finger) to break up any tissue that may be obstructing finger movement. The needle movement may be controlled by ultrasound energy. This is known as percutaneous release;
• A surgeon can make a small cut near the base of the finger and then cut open the tendon sheath to allow more room for finger movement.