Trigger Finger

Trigger Finger, also known as stenosing tenosynovitis, is a condition in which one of the fingers becomes stuck in a bent position and then suddenly snaps straight, similar to pulling and releasing a trigger. It occurs due to narrowing of the sheath surrounding the tendon in the affected finger, which interferes with smooth tendon gliding. Although any finger can be involved, the ring finger and thumb are most commonly affected.

Trigger finger can occur in adults of any age but is most common between the ages of 40 and 60 years. It is more frequently seen in women than in men. While generally not life-threatening, the condition can cause significant discomfort, reduced grip strength, and limitations in daily activities.

Anatomy and Mechanism

The fingers bend and straighten with the help of flexor tendons, which run from the forearm muscles to the fingertips. These tendons glide through protective tunnels called sheaths, stabilized by pulley-like structures that hold the tendons close to the bone.

In trigger finger, inflammation or thickening occurs at the level of the A1 pulley (located at the base of the finger or thumb). This causes narrowing of the tunnel and sometimes a small nodule develops on the tendon. As a result, the tendon cannot glide smoothly. When the finger bends, the swollen tendon may get stuck behind the pulley, and when it straightens, it snaps with a jerky motion, producing the characteristic “triggering.”

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Causes and Risk Factors

The exact cause of trigger finger is not always clear, but several factors increase the likelihood of developing the condition:

Repetitive hand use or gripping – Frequent forceful movements can irritate the tendons.
Medical conditions – Trigger finger is strongly associated with diabetes, rheumatoid arthritis, gout, and hypothyroidism.
Gender – Women are more commonly affected.
Age – Middle-aged and older adults are at higher risk.
Previous hand injury or surgery – Trauma may predispose tendons to irritation.

Clinical Features

The symptoms of trigger finger may develop gradually or suddenly. Common signs include:

Pain and tenderness at the base of the affected finger, especially in the morning.
Swelling or a palpable nodule at the palm near the base of the finger.
Catching or clicking sensation during finger movement.
Locking of the finger in a bent position, sometimes requiring the other hand to straighten it.
Stiffness, particularly in the morning or after inactivity.
In severe cases, the finger may remain locked in a bent or straight position.

Diagnosis

Physical examination: The physician checks for tenderness at the base of the finger, presence of a nodule, and observes the triggering or locking phenomenon.
Medical history: Information about risk factors such as diabetes or repetitive activities is considered.
Imaging: X-rays are rarely necessary, as they usually appear normal. Ultrasound can sometimes show tendon swelling, but it is not routinely required.

Treatment

Treatment of trigger finger depends on the severity of symptoms, duration, and patient-specific factors such as underlying medical conditions.

1. Non-Surgical Management

Rest and activity modification: Avoiding repetitive gripping or heavy hand use may reduce symptoms.
Splinting: Wearing a splint to keep the finger straight can rest the tendon and decrease irritation.
Nonsteroidal anti-inflammatory drugs (NSAIDs): Medications like ibuprofen help relieve pain and reduce inflammation.
Steroid injections: A corticosteroid injection into the tendon sheath is highly effective in many cases, reducing swelling and restoring smooth tendon movement. Success rates are high, though recurrence may occur, especially in diabetic patients.

2. Surgical Management

Complications

Permanent contracture – The affected finger may become stiff and remain bent.
Loss of function – Difficulty in gripping and performing daily activities.
Tender scar or nerve irritation – Possible after surgery, though rare.
Recurrence – Triggering can occasionally return after treatment, especially in patients with diabetes.

Prognosis

The outlook for trigger finger is excellent. Many patients respond well to conservative treatments such as rest, splinting, or injections. For those requiring surgery, long-term results are generally very good, with most regaining full finger motion and strength.

Conclusion

Trigger finger is a common hand condition that interferes with normal finger movement, often causing pain, stiffness, and locking of the digit. It results from narrowing of the tendon sheath at the A1 pulley, leading to impaired tendon gliding. While the condition can be bothersome, it is usually not dangerous and has effective treatments ranging from rest and splinting to steroid injections and minor surgery. Early recognition and treatment can prevent complications and restore full hand function, allowing patients to return to their regular activities without limitation.

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