Trigger Finger

 
 
What is Trigger Finger?

Trigger finger presents with pain and stiffness when moving the finger. It may demonstrate snapping during movement and in the later stages may become locked in a flexed position, needing help to extend it, or it may only be able to have limited flexion.

This happens when there is swelling and narrowing of the tendon sheath in the palm (the hood anchoring the flexor tendons to the bone), causing constriction of the flexor tendon at the entrance of the sheath. A nodule forms when the tendon fibres bunch up at the entrance and when the tendon is finally force through, it “triggers”.
What causes it? How to diagnose?

There is no single cause and most cases are a result of accumulated wear and tear and overusage of the hand. The middle, ring and thumb are commonly affected. Typical age of patients presenting are from the 5th decade onwards. Symptoms are often worse in the morning and improves as the day progresses. Diagnosis is by history and physical examination.

Treatment

Mild cases can afford a trial of splinting and rest.
Injection of the flexor sheath with a small dose of steroids is an effective way to treat trigger fingers. The triggering takes a few days to resolve after the injection and is curative for 50% of the cases. If it recurs, a second injection can be repeated. Steroid injection needs to be done with aseptic technique because it is important to prevent infections with steroid injections.

Surgical treatment

Surgery is curative for recurrent cases. The aim of surgery is to release the thickened sheath, allowing the tendon to glide freely during bending and straightening the finger. This short procedure is usually done as a day surgery under local anaesthesia.

The affected digits should recover normal function after surgery. Therapy is needed for patients with advanced triggering with finger joints contracted. This can take 3 months to straighten out the joint. Early treatment gives the best results.