The forearm muscles are attached to the bones of fingers with the help of tendons. In a healthy finger, the flexor tendons are covered by a tendon sheath with an associated pulley, allowing the tendon to flex and extend smoothly when the muscle contracts and relaxes. A trigger finger is caused when the tendon in the finger gets enlarged, or sheets around the tendon get thicker, and the tendon gets stuck in it. Due to this, the affected finger gets stuck in a bent position at the level of the A1 pulley and gets locked. A popping sound is produced when we try to unlock the finger and extend it. The condition may also be known as stenosing tenosynovitis. A similar condition can occur in the thumb, called the trigger thumb.
The cause of the trigger finger is the inflammation of the tendon sheath due to any irritation. If the inflammation in the tendon sheath stays long-term, scarring and thickening of the sheath can occur. A nodule can also be formed on the tendon, which makes bending and extending the finger more painful and produces popping sounds. People who make use of their fingers or thumb forcefully, more frequently, and make gripping and grasping movements with their fingers are prone to developing this condition because it is most commonly due to repeated aggressive movements of fingers or thumb.
Trigger fingers can occur at multiple levels depending upon their severity.
● Level 1 trigger finger is when there is pain experienced in the palm and tenderness at the A1 pulley.
● Level 2 trigger finger presents with the locking of the digit.
● In level 3 trigger finger, locking of the digit occurs, but it is corrected passively.
● Level 4 trigger finger has the digit locked and fixed.
Common risk factors for trigger finger are;
● Conditions like diabetes mellitus, rheumatoid arthritis, hypothyroidism, and gout put a patient at higher risk.
● Generally, women are affected more than men.
● People with jobs requiring them to make forceful gripping and grasping movements are more likely to develop this condition.
● People who have had carpal tunnel syndrome surgery have a higher risk of developing trigger fingers, especially in the first six months after getting the surgery.
Trigger finger occurs in approximately 2% of the general population in the United States and is mostly seen in women in their fifth or sixth life decade.
If you are suspected of having a trigger finger, these are the symptoms you should look for;
● Painful sensation while flexing or extending the finger.
● A bump present near the joint of the finger; is called a nodule.
● A clicking sound is produced while bending or straightening the finger.
● Your finger gets locked frequently, and you cannot straighten it.
You experience stiffness in the finger after waking up.
When diagnosing a trigger finger, your doctor will ask you to flex and extend your fingers to check if the finger gets stuck in between. He may also examine your fingers for the presence of any thickening or lumps and any tenderness over the tendons. Usually, there are no x-rays required to diagnose a trigger finger.
Conditions that are related to a trigger finger, maybe;
● Dupuytren’s contracture – a condition in which one or more fingers are pulled into the palm in the bent position.
● De Quervain’s disease – a condition in which the thumb tendons are affected and cause pain in the wrist.
● Flexor tendon sheath tumor.
● Focal dystonia of hands – muscle twitches.
● Metacarpophalangeal joint sprain.
● Fraction or dislocation of the bones in hands.
Its treatment depends on how severely and long the finger is affected. Few non-surgical treatment processes are;
Rest – your doctor must advise you to stop making forceful movements that put any strain on your tendons.
Splinting – you will be given a splint to wear overnight for up to 6 weeks to keep your finger in an extended position, which will help it to rest.
Stretching – light stretches may help improve stiffness and range of motion.
Steroid injections – are injected into the flexor tendons at the base of the finger and help relieve the symptoms.
Medications –non-steroidal anti-inflammatory drugs may relieve the pain without treating the swelling. They include ibuprofen, naproxen, and acetaminophen.
When the non-invasive treatments don’t work, doctors suggest surgical procedures to treat a severe trigger finger completely and make the finger as normal as before. They include;
1. Percutaneous release
In this procedure, the doctor inserts a needle around the affected tendon after numbing the palm area. Then the needle is moved around the constricted area to help loosen it out and release the A1 pulley. This procedure is done with the help of ultrasound to ensure there is no damage to the actual tendon or nearby nerves by the needle.
This procedure is performed in an operating room. First, an oblique, transverse, or longitudinal incision is made at the base of the affected finger. The doctor releases the A1 pulley through the incision, causing the tendon not to move freely.
Patients with diabetes have a non-favorable prognosis. Some cases of the trigger finger may resolve themselves spontaneously, while in others, there is progressive pain over the A1 pulley, which progresses to a locked flexed digit. Up to 90% of non-diabetic patients are relieved after only injections.
Certain lifestyle changes, such as minimizing the strain on your finger and avoiding forceful movements, often prevent trigger fingers from occurring again.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on June 01, 2023.
Trigger Finger - Trigger Thumb - OrthoInfo - AAOS
Trigger finger: An overview of the treatment options : JAAPA (lww.com)