Trigger finger

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Trigger finger, trigger thumb, or trigger digit.

Refers to stenosing tenosynovitis.

Affects  2% of the general population and up to 20% of the people with diabetes.

It most frequently affects the ring finger and it is more common in women than men.

The thumb is the second most common phalanx to be affected.

Diabetics often have multiple affected digits with studies reporting prevalence of approximately 4 to 55%.

Characterized by catching, snapping or locking of the involved finger flexor tendon, associated with dysfunction and pain.

There is a disparity in size between the flexor tendon and the surrounding retinacular pulley system, most commonly at the level of the first annular (A1) pulley.

It occurs when smooth flexion and extension of the affected finger is lacking owing to a sized  discrepancy  between the tendon being larger or wider, and the flexor tendon sheath in which it resides being smaller or narrower.

The process results in difficulty flexing or extending the finger and the triggering phenomenon.

When the finger unlocks, it pops back suddenly, as if releasing a trigger on a gun.

Inflammation is not a predominant feature.

There is irregular connective tissue, chondrocyte metaplasia and lack of inflammatory changes within the first annular pulley of the flexor tendon sheath.

Such changes thicken the flexor tendon  sheath in the Palm and Flex or tendon causing mechanical obstruction during flexion or extension of the affected finger.

Speculated that repetitive forceful use of a digit leads to narrowing of the fibrous digital sheath in which it runs, but there is little scientific data to support this.

The relationship to work activities is debatable.

There is some evidence that triggering of the thumb is more likely to occur following surgery for carpal tunnel syndrome, and it may also occur in rheumatoid arthritis

Diagnosis is made almost exclusively by history and physical examination alone.

More than one finger may be affected at a time.

It usually affects the index, thumb, middle, or ring finger.

The triggering is usually more pronounced while gripping an object firmly.

It typically presents with subtle pain along with first annular  pulley distribution located in the distal Palm at the metacarpal head, crepitus with motion, or a palpable tendon nodule along the tendon.

With more advanced disease there is an inability to fully flex or extend the finger, locking of the finger in flexion, and painful popping of the finger with flexion or extension.

Differential diagnosis: infection, extensor tendinitis, arthritis, Duputren’s contracture, and carpal tunnel syndrome.

Injection of the tendon sheath with a corticosteroid is effective over weeks/months in more than half of cases.

When corticosteroid injection fails, the process can resolved by a simple surgical procedure, as a surgeon cuts the sheath that is restricting the tendon.

The most cost-effective treatment is two trials of corticosteroid injection, followed by open release of the first annular pulley.

The natural history of disease for trigger finger is uncertain.

There is some evidence that idiopathic trigger finger behaves differently in people with diabetes.

Recurrent triggering is unusual after successful injection and rare after successful surgery.

Difficulty in extending the proximal interphalangeal joint may persist, but benefits from exercises to stretch the finger straighter.

Trigger finger can leave the finger or thumb stuck in a crooked position.

Causes pain and stiffness and makes it hard to move the affected digit.

Characterized by the fingers getting stuck in a particular position.

It is stenosing tenosynovitis that allows the finger to get stuck in a particular position at one or more of the joints.

Can affect any finger or the thumb and can occur in one or more fingers.

When the tendon sheath becomes inflamed, it can make movement difficult and results in trigger finger.

The symptoms are: pain at the bottom of the finger or thumb when it moves or is pressed on, stiffness or a clicking sound when moving the finger or thumb, and with progression of the process the finger or thumb may curl and get stuck, before straightening suddenly

There is loss of the ability to bend or straighten the finger or thumb.

Can affect any digit.

Most commonly occurs in the fourth and fifth fingers of the hand and the thumb.

There are three types of surgery for trigger finger surgery.

A surgeon makes a small incision in the palm of the hand and then cuts the tendon sheath to give the tendon more room to move.

Percutaneous release surgery: a surgeon inserts a needle into the bottom of the digit to cut the tendon sheath.

Tenosynovectomy: if the first two options are not suitable, a tenosynovectomy involves removing part of the tendon sheath, allowing the finger to move freely again.

Open surgery has traditionally been pref2242ed.

Trigger finger surgery is usually effective, and the problem is unlikely to reoccur after surgery.

There is an equal level of long-term satisfaction with both open and percutaneous release.

If left untreated, trigger finger can become permanent,with the affected finger or thumb becoming stuck in one position.

It is curable without surgery in most cases.

Non-surgical treatments include:

Strapping or splinting the digit to stop it moving.

Anti-inflammatory medications

Injecting steroids into the base of the affected digit to reduce swelling, is effective.

Steroid injections are not as effective in insulin-dependent diabetics.

Steroid injections are associated with: fat necrosis, skin depigmentation, and rarely spontaneous rupture of the flexor tendons.

Surgical options include open or percutaneous first annular pulley release, which is transaction of the pulley where the tendon has restricted motion through an incision in the distal palm.

Surgery is associated with improved symptom resolution and lower recurrence rates than steroid injection.

Percutaneous release compared to open surgery have similar efficacy.

Reducing or temporarily stopping the activity that causes pain.

Around 20 to 50 percent of patients need surgery to correct the condition.

Trigger finger in children can often be treated with stretching and splints.

There is lack of benefit for long-term use of orthoses.

Complications if surgery include:

scarring

infection

pain, stiffness