It is when the tendon of the finger gets stuck in a bent position, towards the side of the palm of the hand (picture a finger when it is in a position to pull the trigger of a gun). This causes the finger to remain bent because of an inability of the tendon to slide through a tunnel. Trigger finger can affect any of the fingers, including the thumb and usually gets worse over time until your finger is unable to straighten at all. Most patients complain of pain and a clicking sound when they pull their finger straight.
How does a trigger finger develop?
The tendons in the hand need to slide through a narrow opening and these openings consist of rings of rigid bands of tissue. Like a rope that is pulled along a pipe needs to be kept in position by anchors to keep the rope in place as the rope slides forwards/backwards. We call these anchors pulleys. These pulleys keep the ropes (tendon) in position against the bone. The tendons straighten and bend the bones in your fingers by using the pulleys as anchor points. If there is a thickening of the ropes(tendon) before it passes through the pulley, it will block the tendon from sliding through the narrow channel. It may stop the movement of the tendon and your finger will stay bent.
During a trigger finger, the tendon itself becomes inflamed and swollen, which results in a thickening of the tendon on the one side of the pulley. In the early stages of a trigger finger you may be able to force the thickened part of the tendon through the pulley, by forcefully straightening your finger. This may cause considerable amount of pain because it is forcing the tendon through the narrow channel of the pulley. A clicking sound might be present as the finger is straightened.
Eventually the tendon will be unable to slide through the channel and leaving your finger stuck in a bent position.
Imagine trying to pull a rope with a knot through a hose pipe…
Causes of Trigger finger
Repetitive movements may put excessive strain on the tendon which leads to a Tenosynovitis. Tenosynovitis is an inflammation of the sheath that surrounds a tendon.
The repetitive friction caused by the tendon passing through the pulley will inflame the outer membrane of the tendon, leading to a cycle of progressive thickening of the tendon that will eventually stop the tendon’s movement.
In some cases any hard blow to the palm of the hand over the first knuckle may trigger the same effect, like catching a cricket ball, slamming your hand in a door.
Symptoms of Trigger finger
- Nodule on the palm side of the knuckle
- 2nd knuckle gets stuck in a bent position
- Painful to straighten the ‘stuck’ finger
- Hearing a clicking sound when straighten the knuckle.
Bend your finger to make a fist, if you try to open all your fingers, you will find that one will stay bent. If you have to use your other hand to help the finger straighten and you hear a click or its quite painful, the test is positive for a trigger finger.
How bad is it?
If your finger is still able to open to a straight position, it is still in the early stages, especially if you only experience it every now and then, but be warned that it could progress and get much worse.
If you are unable to straighten your knuckle, it has entered a more severe stage, and may cause permanent impairment.
We are experienced in testing the different types of problems that can cause your finger pain. Our specialists use a variety of tendon gliding techniques to determine the extent of the damage. The core of the assessment involves testing of the tendon’s ability to move & slide. We develop a certain dexterity to detect a pulley problem.
If your test results prove that we suspect that you may have another problem relating to the tendon, we will require further investigation. The first on the list will be a Sonar.
X-rays will be an unnecessary test, as the bones are still normal, and the joints are not influenced. So X-rays will be redundant in this case.
This is a very useful tool to see in detail the extent of the damage, but any skilled hand therapist will be able to diagnose a trigger finger without an expensive MRI.
Sonar (Diagnostic Ultrasound):
A sonar can determine the thickness, and degree of swelling of the tendon. Even better, the sonographer will be able to show you a live video that shows the thickened part of the tendon as it is unable to glide through the pulley. This is called a functional sonar.
Why is a trigger finger not going away? (Cycle)
The normal healing process is a inflammatory reaction which involves a lot of cells that need to infiltrate the area (swelling), this means that there is an accumulation of a lot of cells in a confined space in your finger. This swelling can contribute to the problem by causing the tendon to thicken even more.
We use our hands every second of every day, these movements may cause repetitive friction of a vulnerable part of the tendon that can cause the tendon to become swollen and prevent healing to take place.
What makes a Trigger finger Worse
Every time the tendon has to be forced through the pulley (narrow channel) it may trigger more swelling and cause the finger to get stuck more frequently accompanied by more pain.
A big problem we see with a Trigger finger these days:
After a patient has had surgery there is scar tissue formation on the wound that forms into a scar. Scar tissue is a dense tissue that looks like a spider web. It helps to close a wound very well, but in some cases, it can restrict the normal slide of the tendon. Seeing a therapist is very important to ensure that scar tissue is guided to prevent any restriction on the tendon as it glides through the pulley.
Waiting too long
When you wait too long before getting treatment the tendon damage can progress too far, making it very difficult to regain full use of the finger. Research has shown that if moderate symptoms occur for longer than 6 months, the effects of conservative treatment is less successful. If your pain does not relieve in 2 weeks you might want to consider asking our advice.
OT Hand therapist treatment for Trigger finger:
Splinting – We protect the flexor tendon by immobilizing the PIP joint using a custom splint. The splint is made on the finger and will fit perfectly.
Exercises – We focus on getting the muscles and tendon stronger by guiding your through a gradual progression as you get stronger. The tendon will need gradual loading exercises to recondition the tendon.
Tendon gliding – Getting the tendon free from the obstruction, and the restoring its normal slide through the pulley tunnel.
Sensory retraining – To restore the normal feeling in your fingers.
Oedema management – Reduce swelling in and around the hand and fingers
Ergonomics – Changing or adapting activities, tasks or the environment to reduce the risk of a repetitive strain or injury.
Phases of Rehabilitation & Treatment:
Immobilization (Approx 2 weeks)
- Reduce pain, Inflammation
Regain normal tendon glide (2 weeks)
- Regain active pain free Range
- Restore normal joint movement without finger getting stuck
Strength & Conditioning (4 weeks)
- Isometric Strengthening
Overall total recovery of a trigger finger may take 6 – 8 weeks, depending on how willing you are to follow our instructions and exercise program.
- Corticosteroid injections – always must be combined with a finger splint and immobilization protocol.
Surgery of a Trigger finger
Only after our conservative treatment program has failed, any respectable orthopedic surgeon will first consider sending you to our practice before putting you under the knife.
If the trigger finger has been fixed in a bent position for more than 2 years, the joint and surrounding soft tissue structures may be past the point of normal recovery and you will need surgery to correct the deformity.