Trigger finger is a condition that causes pain, stiffness, and a sensation of locking when you move your finger (bend and straighten). This is also known as “stenosing tenosynovitis.” The ring finger and thumb are most commonly affected by trigger finger, however, it can occur in the other fingers as well.
When the thumb gets affected, the condition is called a “trigger thumb.”
The flexor tendons are long cord-like structures that attach the muscles of the forearm to the finger bones. When these muscles contract, the flexor tendons allow the fingers to bend.
Each one of these flexor tendons pass through a tunnel in the palm and fingers. It allows the tendons to glide smoothly as the fingers bend and straighten. This tunnel is named the “tendon sheath.”
Along the tendon sheath, tissue bands called “pulleys” hold the flexor tendons closely to the finger bones. The tendons pass through the pulleys as a finger moves. The pulley at the base of the finger is called the “A1 pulley.” This is the one most often involved in trigger finger.
The tendon sheath attaches to the finger bones and keeps the flexor tendon in place as it moves. The A1 pulley is near the opening of the tendon sheath.
In a patient with trigger finger, the A1 pulley gets inflamed or thickened, making it harder for the flexor tendon to glide smoothly through it as the finger bends. Over time, the flexor tendon may also get inflamed and develop a nodule on its surface. On flexion, when the nodule passes through the pulley, there is a sensation of catching or popping. Often this is painful.
When the thickened nodule on the flexor tendon strikes the A1 pulley, it becomes difficult to straighten the finger.
In a severe case, the finger locks and becomes stuck in a bent position. Sometimes the patient must use the other hand to straighten the finger.
The causes of trigger finger are not well understood, but there are several factors that may increase your risk of developing the condition. These include:
- Medical conditions. Trigger finger is more common in people with certain medical conditions, such as diabetes and RA (rheumatoid arthritis).
- Forceful hand activities. The condition occurs after forceful use of the fingers and thumb.
Symptoms of trigger finger generally start without any injury. However, they may follow a period of heavy or extensive hand use, particularly pinching and grasping activities.
This patient’s finger is locked in a bent position.
Symptoms may include:
- A tender lump at the base of the finger on the palm side of the hand
- A catching, popping or locking sensation with finger movement
- Pain at bending or straightening the finger
Stiffness and locking tend to worsen after periods of inactivity, such as when you wake up in the morning.
In severe cases, the affected finger may become locked in a bent position.
Your doctor will be able to diagnose a trigger finger by understanding your symptoms and examining your hand. Typically, x-rays or other tests are not needed.
During an examination, your doctor will look for:
- Tenderness over the flexor tendon sheath in the palm of your hand
- Thickening or swelling of the tendon sheath
- Triggering when you bend and straighten your finger
During the examination, your doctor will check your finger for stiffness and any signs of locking.
Initial treatment for a trigger finger is generally nonsurgical.
Rest. Resting your hand and avoiding activities that worsen the symptoms may be enough to resolve the problem.
Splinting. Wearing a splint at night to keep the affected finger or thumb in a straight position may be helpful.
Exercises. Gentle stretching exercises can decrease stiffness and improve range of motion in the involved digit.
Medications. Over-the-counter medications, such as acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs), can help reduce/relieve pain and inflammation.
Steroid injections. Corticosteroid is an anti-inflammatory agent that can be injected into the tendon sheath at the base of the trigger finger. This may resolve the triggering within a period of one day to several weeks. If symptoms do not improve, a second injection may be given. If two injections do not help the problem, surgery can be considered.
Steroid injections, however are less likely to be effective in patients with diabetes, but may still help avoid surgery. They can potentially cause a short-term rise in blood sugar, so glucose levels in diabetic patients must be monitored after injection.
Steroid being injected into the A1 pulley.
If your finger does not get better with nonsurgical treatment, you may wish to consider surgery. Surgery is elective. The decision for surgery is based on how much pain or loss of function you have in your finger. If, however, your finger or thumb is stuck in a flexed or bent position, your doctor may recommend surgery to prevent permanent stiffness.
Surgical procedure. The surgical procedure performed for trigger finger is called “tenolysis” or “trigger finger release.”
The procedure is performed to release the A1 pulley that is blocking the tendon movement, so the flexor tendon can glide easily through the tendon sheath. Typically, the procedure is performed in an outpatient setting with local anesthesia injection to numb the area for surgery.
Surgery is carried out through either a small open incision in the palm or with the tip of a needle. The A1 pulley is released (divided) so that the flexor tendon can glide freely.
Complications. Complications are a side effect with any type of surgery. Your doctor will discuss the risks involved in the surgery and will take specific measures to help prevent any complications.
The most common complications following surgery for trigger finger or trigger thumb include:
- Stiffness in the involved finger.
- Inability to straighten the involved finger. If you were not able to straighten your finger completely before surgery, you may not be able to do so afterward.
- Temporary soreness or swelling at the surgery site
Some less common complications include:
- Persistent locking or clicking. This may indicate that still more of the pulley needs to be released or may be caused by any other problem in your finger.
- “Bowstringing.” In a small number of cases, the tendon may “bow” away from the bone, resulting in a reduced range of motion. Bowstringing occurs when one of the more important pulleys is released.
- Infection (rare)
- Digital nerve injury. This may cause numbness or tingle alongside the part of the finger affected.
Recovery. Most patients are encouraged to move the finger immediately after the surgery.
You may have some soreness in your palm. Elevating your hand above your heart level can help reduce pain and swelling.
Although your incision will heal within a few weeks, it may take about 4 to 6 months for the swelling and stiffness in your hand and fingers or thumb to go away completely.
If stiffness, swelling, or pain persists after surgery, your doctor may recommend you to a hand therapist.
Outcome. Patients who undergo surgery experience a significant improvement in function as well as relief from pain. Still, if a contracture or loss of motion was present before the surgery, complete range of motion may not return