Trigger finger is a disorder that causes you to experience a “locking” or “catching” sensation when you try to bend or straighten your finger. You also experience finger stiffness and pain around the base of the finger as part of the condition. The technical name for this condition is “stenosing tenosynovitis”.
The fingers that are most often affected are the thumb and ring finger but trigger finger can sometimes affect the other digits also. “Trigger thumb” is the name sometimes used for the condition when the thumb is affected.
This condition is more common in women than in men. It also appears to be linked to certain other health conditions such as diabetes.
The forearm muscles connect to the finger bones by way of flexor tendons. These tendons pass through a tunnel that extends through from the base of the finger and continues along its length.
In a healthy finger, this tunnel (or sheath) allows the tendon to glide smoothly along its interior as you bend and straighten your finger.
Bands of tissue (known as pulleys) lining the sheath keep the flexor tendon in close proximity to the bone that it controls. The pulley at the base of the finger is called the A1 pulley. It is this pulley that usually causes trigger finger (see below).
As you move your finger, the tendons pass through the pulleys.
What Causes Trigger Finger?
Trigger finger is the result of a pulley (usually the A1 pulley) thickening due to becoming irritated and then inflamed. Once this happens, the flexor tendon cannot easily pass through the tendon sheath when you try to bend or straighten your finger.
With the passage of time, the friction between the tendon and pulley causes the tendon itself to become inflamed. Small bumps (called nodules) form on the surface of the tendon. These increase the difficulty of pulling the tendon through the sheath and this in turn causes further inflammation.
In the early stages, you may simply experience “snapping” or “popping” when you try to bend or straighten your finger. You may also feel some pain with these sensations.
Ultimately, if the condition is left untreated, the finger may become locked in a bent position. Progressively greater effort is required to straighten it. In some cases, the trigger finger patient may have to use the other hand to straighten the bent finger.
Researchers have not definitely established what causes the flexor tendon to become inflamed. However, research as established that the following tends to increase your risk of developing the condition:
Being female, as trigger finger occurs more frequently among women;
Working in a job that requires plenty of forceful gripping movements with the fingers and thumb.
The symptoms of trigger finger usually include the following:
Finger stiffness and reduced range of motion due to resistance to bending or straightening the digit;
A catching, locking or “popping” sensation when you try to bend or straighten your finger;
Pain that accompanies bending or straightening of your finger;
A lump on your palm at the base of the affected finger. .
The finger stiffness and popping may be worse upon awakening in the morning or after a period of inactivity.
In severe cases, the patient may find the finger locked in a bent position and be unable to straighten it without using the other hand.
Your doctor will likely ask you about your symptoms and conduct a physical examination of the affected hand and fingers.
The physical exam will involve looking for the telltale bump (described above) at the base of the affected finger. The doctor will also verify the finger snapping or popping when you try to move the digit.
Treatment Of Trigger Finger
As with most injuries of this type, initial treatment plans usually focus on non invasive homed based protocols. These may include:
Resting the hand and fingers by avoiding activities that require powerful or frequent gripping;
Wearing a finger sprint such as the BioSkin Thumb Spica (in the case of trigger thumb). These splints will keep the finger fixed in a straight position and avoid further tendon aggravation due to finger movement.
Physical therapy stretching exercises may help to reduce finger stiffness and restore range of motion;
Use of nonsteroidal anti inflammatory drugs (NSAIDs) to reduce tendon inflammation and relieve pain.
If home based treatments do not produce the required results, your doctor may suggest cortisone steroid injections. The cortisone will be injected into the tendon sheath at the base of the finger. A repeat injection may be tried if the symptoms do not improve.
If things do not improve after two injections, your doctor will probably suggest surgery.
If all else fails, surgery can be performed to cut open the tendon sheath and allow the tendon more room to move freely.