Trigger Finger /Trigger Thumb

Trigger finger is a common disabling condition which usually present in the surgical clinic.

The presentation would be pain, stiffness and sensation of locking of finger/thumb when it is flexed. Patient should passively manipulate the finger/thumb to get it into the extended position. Even though this condition can affect any finger most commonly thumb (Trigger Thumb) and the ring finger (Trigger Finger) are affected.

This triggering is caused by the fibrous thickening of the flexor tendon sheath usually at A1 pulley where the tendons enter the tendon sheath.

Tendon Sheath and A1 Pulley

Exact cause unknown and occasionally congenital and traumatic. Most of the time it is associated with diabetes and rheumatoid arthritis.

Common signs and symptoms of trigger finger are

  1. Locking or catching during active flexion-extension activity  
  2. Triggering on active or passive extension by the patient
  3. Palpable snapping sensation over the A1 pulley
  4. Feel pain( Tenderness) when press over  the A1 pulley
  5. May be a palpable nodule
  6. Fixed deformity can be seen in untreated conditions
  7. There may be early feature of triggering in other fingers

The diagnosis is done with clinical history and examination. No laboratory test or imaging is not needed. But most of the times a fasting blood sure or HbA1c would be done for excluding diabetes, and sometimes rheumatoid factor if history suggestive of rheumatoid arthritis.

When you are having such symptoms you should be consult a general surgeon, orthopedic surgeon or a plastic surgeon.

I you have mild pain, symptoms and no significant disability can be observed with pain killers and physiotherapy.

But most of the time injection of corticosteroid to the tendon sheath would be the first line treatment. This would be done in the clinic setup. Under sterile conditions, doctor would inject steroid with local anesthetic agents (about 1ml) into the tendon sheath at the base of the trigger finger. Patient may feel instant symptomatic relief if drug is injected correctly, but it will take over a period of one day to several weeks for recovery.

But if symptoms do not improve another injection may be given. But if two injections do not improve the condition, surgery would be considered.

The goal of the surgery is to release the tendon sheath (A1 pulley), so the tendon can freely glide without friction. 

Usually it can be done as an outpatient procedure under local anesthesia, but ideally it should be done in an avascular field with a tourniquet. Therefore it any done under general anesthesia.

Surgery is performed through either a small open incision in the palm. The A1 pulley is released, therefore the flexor tendon can glide freely. Even though the bowing of the flexor tendon after dividing the tendon sheath is a problem, it would not cause significant disability in the future.

As in any surgery, there are common complications like wound infection and pain. The specific complications here are as mentioned previously the bowing of the tendon and possibility of damaging the digital nerve which may cause tingling sensation over the side of the finger.

Skin would be sutured with non-absorbable sutures most of the time, and the sutures would be removed after two weeks.

Alternatively ultrasound guided percutaneous incision of the sheath is commonly practiced in other countries but less common in Sri Lankan setup.

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