If a finger suddenly gets stuck while gripping something and then snaps forward abruptly, it is usually a case of trigger finger. This common condition, medically known as stenosing tenosynovitis or trigger finger, is caused by a narrowing of the flexor tendons within the tendon sheath. Due to a nodular thickening of the tendon or a thickening of the ring ligament, the tendon can no longer glide smoothly. Instead, it gets stuck when bending or straightening and often has to be released with the other hand, which is very painful. Whether conservative treatment with rest and cortisone is sufficient or whether a minor surgical procedure—a ring ligament release—is necessary depends on how severely the finger is locked.
Definition of Stenosing Tendovaginitis
Trigger finger is a usually painful gliding disorder of the flexor tendons on the palm side of the hand, above the metacarpophalangeal joint. Here, the superficial and deep flexor tendons glide beneath the so-called annulus, which holds the tendons close to the bone when they are taut. Thickening of the tendons and the surrounding tissue leads to narrowing beneath the annulus.
Often, an hourglass-shaped groove forms in the tendon beneath the annulus while at rest—usually at night in a relaxed flexed position. This causes the tendon to become blocked at that point, and the affected finger can only be extended again with a sudden, forceful jerk (the typical snapping phenomenon). One tendon, several at the same time, or several over time may be affected.
The symptoms most commonly occur in middle-aged women. Children and toddlers can also be affected; in these cases, it usually involves the thumb, with the distal joint locked in a flexed position.
Causes of Trigger Finger
The causes are unclear. Several possibilities are being considered:
- Excessive mechanical stress, such as repeated firm gripping
- Congenital thickening of the hand’s contours with age, leading to a faster increase in tendon cross-sectional area relative to the annulus
- Thickening of the tendons due to rheumatic or metabolic diseases (e.g., diabetes mellitus)
Diagnosis of Trigger Finger
The diagnosis is based on the typical symptoms.
Pain is usually felt over the corresponding ring ligament on the flexor side at the level of the metacarpophalangeal joint. The pain can be provoked by pressure. A hardening is often palpable in this area as well.
In advanced stages, a so-called snapping phenomenon may develop. In this case, the finger can only be straightened with the help of the other hand.
Special diagnostic imaging procedures, such as X-rays, are not usually necessary.
Treatment of Trigger Finger
The goal is to enable the tendon to glide smoothly without pain and to eliminate the snapping phenomenon. Both conservative (non-surgical) and surgical options are available.
Conservative measures include
- temporary rest (possible cast immobilization),
- anti-inflammatory medications (such as diclofenac and indomethacin),
- local cortisone injections, and
- local cooling
. However, these measures often do not lead to lasting success, especially if the snapping phenomenon is pronounced.
If surgery is necessary, it is usually performed on an outpatient basis under local anesthesia. To do this, after administering anesthesia, the surgeon makes an incision approximately 1 to 1.5 cm long along the transverse palmar crease. In doing so, he preserves the vascular and nerve structures running parallel to the affected tendon. The surgeon then cuts through the constricting ring-like band over the tendon at its center and partially removes it.
The surgeon then pulls the superficial and deep flexor tendons out of the surgical incision. This allows him to check that the tendon can glide freely again. Any other abnormalities in the tendon are also ruled out in this way.
The skin is then usually closed with a suture, and a compression bandage is applied.
Significant pain usually does not occur once the anesthesia wears off. If necessary, a mild pain reliever (e.g., ibuprofen) may be administered.
Risks and Complications of Trigger Finger Surgery
Complications such as
- a wound infection,
- injury to blood vessels or nerves, and
- the development of painful scars
are very rare.
Follow-up Care for Stenosing Tendovaginitis
One day after surgery, the compression bandage is removed and replaced with a simple adhesive bandage.
The patient should begin active finger exercises as soon as possible after surgery. This helps prevent the tendons from adhering to one another. These exercises can be performed independently following instructions.
After 1 to 2 follow-up wound checks, the sutures can be removed after 12 to 14 days. A bandage or adhesive dressing is then no longer necessary. The hand can then gradually be used to its full capacity again.
Only extreme strain, such as climbing or gripping with maximum force, should be avoided for approximately another two weeks.
Prognosis for Trigger Finger
In most cases, conservative treatment does not lead to lasting success. However, the prognosis is very good following surgical release of the ring ligament.
The scar in the palmar crease is generally no longer visible after several weeks to months, and function is fully restored.
FAQ: The 8 Most Important Questions About Trigger Finger
What are the first signs of trigger finger?
Initially, there is often tenderness in the palm, right where the finger meets the hand. Sometimes a small, nodular thickening of the tendon can be felt. Patients report an unpleasant grinding or catching sensation when moving the finger, especially in the morning. Later, the typical snapping sensation develops: The finger can be bent but gets stuck in the bent position and then snaps back into extension abruptly and painfully.
What causes trigger finger?
Trigger finger is caused by a mismatch between the diameter of the flexor tendon and the width of the tendon sheath or the annular ligaments. Due to overuse, chronic inflammatory processes, or metabolic disorders such as diabetes mellitus, the tendon sheath swells or the tendon thickens and becomes nodular. When this thickened portion of the tendon has to glide through the narrow first annulus, it gets caught like a thread in the eye of a needle, which causes the snapping.
How is trigger finger treated?
Once trigger finger is diagnosed, treatment often begins with conservative measures. These include immobilizing the affected finger with a splint and administering anti-inflammatory medications. A local cortisone injection directly into the inflamed ligament is often very effective in reducing the swelling. If this does not provide lasting relief or if the finger is already permanently locked, surgery is the treatment of choice.
How is trigger finger surgery performed?
The procedure, known as ring ligament release, is usually performed on an outpatient basis under local anesthesia. Through a small incision in the palm, the surgeon locates the constricted ring ligament and cuts it lengthwise. This removes the constriction, allowing the tendon to glide freely again. Immediately after the surgery, the doctor checks to see if the snapping has stopped. The wound is sutured, and the finger can and should be moved again right away.
Which fingers are most commonly affected?
The thumb (pollex flexus congenitus in children), the middle finger, and the ring finger are most commonly affected. In principle, however, any finger can be affected, and sometimes the condition occurs in several fingers at the same time. Statistically speaking, women are affected more often than men.
Are there any risks associated with trigger finger surgery?
As with any surgical procedure, there are general risks such as infection or impaired wound healing. Specifically in the hand, nerves can be damaged, which can lead to numbness in the finger; however, this is rare when performed by an experienced hand surgeon. A rare complication is that the finger becomes stiff after surgery or the snapping returns if the tendon was not sufficiently split.
Can trigger finger be prevented?
Since the exact cause of trigger finger is unknown or multifactorial (genetic predisposition, diabetes, rheumatism), targeted prevention is difficult. You should avoid one-sided, repetitive gripping motions or take breaks. Stretching exercises for the hand and specific exercises to move the fingers can help keep the tendons supple. At the first signs, such as morning stiffness, you should rest the finger and apply ice.
When should you see a doctor?
If you experience pain in the palm of your hand, if your fingers catch when bending or straightening, or if you can barely make a fist in the morning, it’s advisable to see a doctor. The earlier trigger finger is treated, the better the chances that conservative measures—such as cortisone injections—will be sufficient and surgery can be avoided.
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