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Mathias Masem, M.D.
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Shoulder | Elbow | Wrist | Hand

Trigger Finger (Stenosing Tenosynovitis)

What is trigger finger or stenosing tenosynovitis?

Figure 1: Normal anatomy flexor sheath showing pulley, tendon, and tenosynovium.

Stenosing tenosynovitis, commonly known as "trigger finger" or "trigger thumb", involves the pulleys and tendons in the hand that bend the fingers. The tendons work like long ropes connecting the muscles of the forearm with the bones of the fingers and thumb. In the finger, the pulleys are a series of rings that form a tunnel through which the tendons must glide, much like the guides on a fishing rod through which the line (or tendon) must pass. These pulleys hold the tendons close against the bone. The tendons and the tunnel have a slick lining that allows easy gliding of the tendon through the pulleys (Figure 1).

Figure 2: Abnormal anatomy showing tendon catching thick, tight pulley. Sometimes the tendon will be locally enlarged and thicker.

Trigger finger/thumb occurs when the pulley at the base of the finger becomes too thick and constricting around the tendon, making it hard for the tendon to move freely through the pulley. Sometimes the tendon develops a nodule (knot) or swelling of its lining. Because of the increased resistance to the gliding of the tendon through the pulley, one may feel pain, popping, or a catching feeling in the finger or thumb (see Figure 2). When the tendon catches, it produces inflammation and more swelling. This causes a vicious cycle of triggering, inflammation, and swelling. Sometimes the finger becomes stuck or locked, and is hard to straighten or bend.

What causes trigger finger / stenosing tenosynovitis?

Causes for this condition are not always clear. Some trigger fingers are associated with medical conditions such as rheumatoid arthritis, gout, and diabetes. Local trauma to the palm/base of the finger may be a factor on occasion, but in most cases there is not a clear cause.

What are the signs and symptoms of trigger finger / stenosing tenosynovitis?

Trigger finger/thumb may start with discomfort felt at the base of the finger or thumb, where they join the palm. This area is often tender to local pressure. A nodule may sometimes be found in this area. When the finger begins to trigger or lock, the patient may think the problem is at the middle knuckle of the finger or the tip knuckle of the thumb, since the tendon that is sticking is the one that moves these joints.

What can you do to help?
  • Ice for five to fifteen minutes at a time on the area swollen and tender.
  • "Over the counter" non-steroidal anti inflammatory medication (NSAID), such as aspirin, ibuprofen, or naprosyn. Check with your pharmacist regarding possible side effects and drug interactions.
  • Avoid activities that involve a sustained grip. Discontinue the use of grip strengthening devices or exercises involving repetitive squeezing - these put stress on the irritated tendon.
  • If fingers bend and lock during the night and are painful to straighten in the morning, it may be helpful to wear a splint to keep them straight while sleeping.
What can a therapist do to help?
  • Help identify aggravating activities and suggest alternative postures.
  • Massage, heat, ice and other treatments aimed at making the area more comfortable.
  • Fabricate a custom splint which limits the finger from bending can help.
What can a doctor do to help?
  • Confirm that this actually is the problem.
  • Prescribe stronger NSAID medication or cortisone type medication.
  • Prescribe hand therapy and/or a custom prescription splint.
  • Give a cortisone shot into the sore area. Usually, no more than two shots are given into one finger because more may Perform surgery.
What is the treatment of trigger finger / stenosing tenosynovitis?

The goal of treatment in trigger finger/thumb is to eliminate the catching or locking and allow full movement of the finger or thumb without discomfort. Swelling around the flexor tendon and tendon sheath must be reduced to allow smooth gliding of the tendon. The wearing of a splint or taking an oral anti-inflammatory medication may sometimes help. Treatment may also include changing activities to reduce swelling. An injection of steroid into the area around the tendon and pulley is often effective in relieving the trigger finger/thumb.

If non-surgical forms of treatment do not relieve the symptoms, surgery may be recommended. This surgery is performed as an outpatient, usually with simple local anesthesia. The goal of surgery is to open the pulley at the base of the finger so that the tendon can glide more freely. Active motion of the finger generally begins immediately after surgery. Normal use of the hand can usually be resumed once comfort permits. Some patients may feel tenderness, discomfort, and swelling about the area of their surgery longer than others.

What happens if you have no treatment?
  • It depends on how much it is bothering you - it really is a quality of life issue. This is not a problem that can spread to other parts of your body. Some people have triggering which resolves over a period of months.
  • Other than persistent pain and stiffness, a permanent partial bend of the middle joint of the finger may occur depending on the length of time the triggering has been going on.
  • Some people will have a mild problem that flares up from time to time. Others have a severe problem that prevents them from doing many things with their finger. At that time, surgery may become a choice.