Trigger finger is a painful condition that causes the fingers or thumb to catch or lock when bent. In the thumb its called trigger thumb.
Trigger finger happens when tendons in the finger or thumb become inflamed. Tendons are tough bands of tissue that connect muscles and bones. Together, the tendons and muscles in the hands and arms bend and straighten the fingers and thumbs.
A tendon usually glides easily through the tissue that covers it (called a sheath) because of a lubricating membrane surrounding the joint called the synovium. Sometimes a tendon may become inflamed and swollen. When this happens, bending the finger or thumb can pull the inflamed tendon through a narrowed tendon sheath, making it snap or pop.
What Causes Trigger Finger?
Trigger finger can be caused by a repeated movement or forceful use of the finger or thumb. Rheumatoid arthritis, gout, and diabetes also can cause trigger finger. So can grasping something, such as a power tool, with a firm grip for a long time.
Who Gets Trigger Finger?
Farmers, industrial workers, and musicians often get trigger finger since they repeat finger and thumb movements a lot. Even smokers can get trigger thumb from repeated use of a lighter, for example. Trigger finger is more common in women than men and tends to happen most often in people who are 40 to 60 years old.
What Are the Symptoms of Trigger Finger?
One of the first symptoms of trigger finger is soreness at the base of the finger or thumb. The most common symptom is a painful clicking or snapping when bending or straightening the finger. This catching sensation tends to get worse after resting the finger or thumb and loosens up with movement.
In some cases, the finger or thumb locks in a bent or straight position as the condition gets worse and must be gently straightened with the other hand.
How Is Trigger Finger Diagnosed?
Trigger finger is diagnosed with a physical exam of the hand and fingers. In some cases, the finger may be swollen and there may be a bump over the joint in the palm of the hand. The finger also may be locked in bent position, or it may be stiff and painful. No X-rays or lab tests are used to diagnose trigger finger.
How Is Trigger Finger Treated?
Most trigger digits in adults can be managed successfully with local steroid injections and splinting. Oral or topical pharmacologic measures have not been demonstrated to be effective.
The outcome of conservative treatment for pediatric trigger thumb is somewhat controversial. A report by Baek et al on the natural history of this condition demonstrated after a follow-up period of 5 years or more in patients who received no treatment for pediatric trigger thumb, complete resolution of flexion deformity occurred in 66 out of 87 thumbs (75.9%), and partial improvement occurred in the remaining 21 thumbs.
Another study, by Lee et al, reported that extension splinting for 12 weeks led to improvement in 71% of thumbs, compared with 23% improvement in patients not receiving any treatment. See also the current recommendations described by Ogino.
The chief indications for surgical management of trigger finger (TF) are as follows:
- Failure of splinting and/or injection treatment
- Irreducibly locked TF
- Trigger thumb in infants (without surgical release, these infants are likely to develop a fixed flexion deformity of the interphalangeal [IP] joint)
Although the results of percutaneous release are well established, the open technique is absolutely essential for the thumb or little finger or in the presence of proximal interphalangeal (PIP) contractures. Percutaneous release should be reserved for the index, middle, and ring fingers.
In a study from Oxford comparing percutaneous and open surgical methods, both procedures displayed similar effectiveness and proved superior to conservative corticosteroid-injection treatment regarding trigger cure and relapse rates.
In children, triggering has varying causes. Release of the A1 pulley alone does not always correct the problem. Additional treatment (eg, resection of 1 or both limbs of the flexor digitorum superficialis [FDS] tendon, A3 pulley release) may be required and is recommended in rheumatoid arthritis (RA) tenosynovitis.
In infants, the nodule on the flexor pollicis longus (FPL) tendon can be resected with good results. Corticosteroid injections are generally not helpful in these cases of trigger thumb.
How Long Does Recovery From Trigger Finger Take?
The time it takes to recover from trigger finger depends on how bad it is. The choice of treatment also affects recovery. For example, splinting may be necessary for six weeks. But most patients with trigger finger recover within a few weeks by resting the finger and using anti-inflammatory drugs.