Trigger Fingers

Written by Dr Richard Lawson FRACS - Hand Surgeon

Introduction

Fingers trigger when the flexor tendons, which bend the finger down into the palm, get caught on the edge of the flexor sheath pulley. The pulleys are rings of tissue which bind the flexors tendons down onto the bones, helping them to bend the fingers effectively. The flexor tendons usually run easily through the pulleys, but sometimes they start to catch on the edge of the pulley. If this occurs, then the flexor tendons can become irritated, and as a result a localized swelling or nodule of the flexor tendon may occur, which will lead only to more catching and more irritation; a vicious circle of catching and irritation can ensue, and eventually the fingers may lock down completely.

Who gets trigger fingers?

Trigger fingers are quite common, and can occur in anyone. They are somewhat more common in patients with diabetes and rheumatoid arthritis, and multiple fingers are often affected in patients with diabetes.

How are they treated?

Splintage is relatively ineffective. The initial treatment in most cases consists of an injection of corticosteroid and local anaesthetic around the nodule. This will act to decrease the inflammation, and in many cases will provide relief. If there is inadequate response to the injection then operative treatment may be required.

How is the corticosteroid injection done?
The solution is infiltrated around the nodule and tendon. There may be some discomfort for several days after the injection, but this typically settles down within two to three days. Applying ice to the hand is effective in treating pain and swelling. Some response to the injection is often seen within one to two weeks. I usually like to see patients around 8 weeks after the injection to assess the effectiveness of the treatment.

Does the corticosteroid have side effects?
The local effects can include temporary pain (common), and very uncommonly changes in pigmentation and/or “fat necrosis” where a small piece of fat around the injection site effectively atrophies, leaving a little indentation. These latter two complications occur well under 1% of the time.

Infection is always a possibility whenever an injection is performed, but the rate of this would be around 1/10 000. If there is increasing pain in the two-three days after the injection you should contact me on my mobile to rule out infection.

Patients with diabetes can notice a climb in their blood sugar levels for 4-5 days after the injection and they should carefully monitor their blood sugar levels and insulin requirements.

What happens if injections are ineffective?
Surgical division of the pulley causing the irritation of the tendon is a simple, effective day stay operation. After the operation it is most important to ensure that you fully straighten out the finger, at least 5 times every hour. The sutures are removed at around 2 weeks after the operation.

What complications can occur following surgery?
Infection occurs in around 1% and can usually be treated with oral antibiotics, or for more severe infections intravenous antibiotics. Much more rare is damage to the surrounding nerves or damage to the tendon itself. Re-operation may occasionally be necessary, but is quite rare.

The main avoidable complication is a flexion deformity of the finger, where the finger bends down at the first joint. This can be avoided if the finger is fully straightened on a regular basis.