Trigger Finger

What is Trigger Finger?

Trigger finger – also known as stenosing tenosynovitis – is a condition that causes one of your fingers to get stuck in a bent condition. It is caused by inflammation, which narrows the space in the sheath surrounding the tendon. Your finger may bend or straighten with a snap or may become completely locked in a bent position. The condition is more common in women and people whose jobs or leisure pursuits require them to make repeated gripping motions.

It can affect any finger, as well as the thumb, and more than one finger can be affected at the same time. It is normally worse in the morning.

What causes trigger finger?

The sheath that surrounds the tendon in the affected finger becomes irritated or inflamed which prevents the tendon from sliding smoothly through the sheath and causes it to stick. If the irritation is prolonged it can produce thickening, scarring and the formation of nodules on the tendon which makes it even more difficult for the tendon to move smoothly. Certain factors can increase the risk of developing the condition, including:

• Activities that involve prolonged gripping and repetitive hand use.
• Health conditions such as diabetes or rheumatoid arthritis.

What are the symptoms of trigger finger?

The symptoms, which may start relatively mild and become more severe over time, include:

• A clicking or popping sensation when you move your finger
• Stiffness in your finger, particularly in the morning
• A lump or pain in the palm at the base of the affected finger
• Your finger locking in a bent position before popping straight
• Being unable to straighten your finger

How is trigger finger diagnosed?

A physical examination will be used to diagnose trigger finger. Your consultant will ask you to open and close your hand and will check for evidence of locking and pain as well as examining your palm for lumps.

How is trigger finger treated?

A physical examination of your arm, elbow and hand will test for strength, sensation and signs of nerve irritation. An X-ray may be used to rule out other causes of elbow pain such as injury, trauma or arthritis. An MRI or ultrasound scan can provide a detailed view of the tissues of the arm and hand. An orthopaedic consultant may use an electromyogram to measure the electrical impulse travelling along the nerves, nerve roots and muscle tissue. By inserting a tiny needle electrode through the skin into the muscle, it is possible to measure the amount of electricity generated by the muscle cells when activated by the nearby nerves. If the little finger or ring finger feels numb or tingly, the consultant may carry out a nerve conduction study to assess for nerve damage. The nerve is stimulated and the time it takes to respond is measured.

An injection of corticosteroids into the tendon sheath may help to reduce inflammation so the tendon can move smoothly again. You may also be offered a percutaneous release treatment which entails inserting a needle into the tissue around the affected tendon and moving it, along with your finger, to break up anything that is constricting the tendon sheath. This is normally done under local anaesthetic and using ultrasound to guide the needle.

In more severe cases, you may be offered surgery to release the affected tendon. A small incision will be made near to the base of your affected finger and the surgeon will cut open the constricted sections of tendon sheath. The incision will be closed with sutures.