Trigger finger, medically known as stenosing tenosynovitis, describes the condition of trying to straighten a bent finger, but having it catch or lock temporarily before suddenly, and sometimes painfully, popping straight.
Tendons are strong cords of fiber that connect muscle to bone. When a muscle contracts or relaxes the tendon, due to its attachment to the bone, causes the body part to flex or extend, that is, bend or straighten. Tendons are kept in place next to the bones by a protective tunnel of tissue called the tendon sheath, through which the tendon slides. The sheath is lined with tenosynovium, a lubricating substance that helps the tendon move smoothly.
In the hand, the particular tendons involved in the movement of the fingers are flexor tendons, which extend from muscles in the forearm through to the bones of the fingers and thumb. They run along the underside, or palm side, of the fingers.
The tenosynovium lining the tendon sheath can become inflamed and thickened through repetitive use or due to a condition such as rheumatoid arthritis. This may cause the available space through which the tendon must slide to narrow, making movement of the tendon more difficult. If this happens and the smooth sliding of the tendon is hindered by constriction at the mouth of the tendon sheath, there can be a sticking or catching before the sudden release and straightening of the finger. Each time the tendon catches, it worsens the inflammation and eventually bumps, called nodules, can form, and permanent thickening and scarring of the sheath can occur. This sets up a vicious cycle of more catching, more inflammation and more swelling.
It can be experienced in more than one finger simultaneously, and sometimes both hands are affected. If it is particularly severe, the finger may become locked in a bent position. It is more common in the dominant hand and the thumb, middle or ring fingers are most often affected.
Trigger finger is caused by the thickening of the tendon sheath and the resulting inability of the tendon to slide smoothly through the restricted space. Certain conditions may predispose people to develop it.
- Being between 40 and 60 years old.
- Being female.
- Having diabetes, rheumatoid arthritis, hypothyroidism or tuberculosis.
- Straining the hand through repetitive or extended gripping. Musicians, people who work with power tools, or industrial workers are the sorts of people who might be at particular risk of developing trigger finger.
- Trying to straighten a bent finger or thumb but having it catch or lock before suddenly shooting straight.
- Pain with snapping or clicking sensation on bending or straightening the finger.
- Tender lump at the base of the affected finger.
- Finger possibly getting stuck in a bent position.
- Stiffness in the finger, especially after inactivity; better after movement.
Your doctor will take a medical history from you, and perform a physical assessment. You may be asked to move your hand in certain ways so your doctor can determine what causes difficulty of motion or discomfort. A simple physical examination is usually sufficient for diagnosis, and x-rays or other tests are not needed.
Treatment for a trigger finger will depend on the severity of the symptoms, and how long you have been afflicted.
Mild cases are usually successfully treated with non-surgical methods.
For symptoms that are more severe, you may be advised to take NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen (Advil) or naproxen (Aleve). These work to lessen inflammation, which may reduce the constriction in the tendon sheath, making it easier for the tendon to slide smoothly. Painful symptoms would therefore be relieved.
- Resting of the affected hand for 4-6 weeks will normally cure the condition.
- Altering your activities to avoid any repetitive gripping motions will allow the hand to rest.
- Massage will relieve pain, but will not reduce inflammation.
- Soaking the hand in warm water in the morning, when the catching is worst, may ease symptoms. This can be repeated throughout the day if it is found to be useful.
- Doing finger exercises are good at maintaining flexibility in the finger.
- Splinting the finger for 6 weeks.
A corticosteroid injection can be administered to the tendon sheath, which also reduces inflammation. These can be very effective, but are sometimes not suitable for people with certain medical conditions such as diabetes or rheumatoid arthritis.
A medical procedure, known as percutaneous trigger finger release, can be performed to release a locked finger and is usually very successful. Moving the finger soon after surgery is recommended to avoid stiffness in the joint.
Performing these exercises will help improve range of motion, flexibility and strength in the fingers. Be guided by your health care professional as to when you can start doing these.
Passive range of motion:
With your good hand holding the affected finger or thumb, gently bend and straighten the finger as far as it will go, without forcing. Repeat 10-15 times.
With the palm of your affected hand facing the floor, hold the trigger finger with your other hand and gently stretch it up towards the ceiling as far as it will go. Hold the stretch 5-10 seconds and then gently stretch it down towards the floor. Repeat the hold and then release. Do this 3-5 times.
Gently squeeze a rubber ball, hold the squeeze for 10 seconds, then release. Repeat 10 times. As strength in the hands builds, you will be able to squeeze harder.
What to look for in a splint:
A splint may have to be worn for several weeks, so a comfortable fit is important, snug enough to prevent movement but not so tight as to be constricting. Construction that includes ventilation for the skin will help to prevent sores. You will probably be able to remove the splint when bathing, just make sure that your skin is thoroughly dry before putting the splint back on.
- Avoid activities that involve extended gripping, if possible.
- Keep your hands and fingers strong and flexible.