Trigger finger

Trigger finger affects the flexor tendons in the palm of your hand. They're responsible for making your fingers and thumbs open and close.

Flexor tendons are tough, string-like structures that attach bones in finger joints at one end and forearm muscles at the other. They're enclosed in a fluid-filled sheath that helps the tendons to glide smoothly. These sheaths are attached to the inside of the finger and thumb joints with small loops or pullies.

When the muscle contracts it pulls the tendon and the joint moves.

In trigger finger, the tendon becomes inflamed or thickened and can’t pass easily through the sheath. This makes it hard to move the affected finger or thumb.

Sometimes the tendon bunches into a small, lumpy knot. This lump catches on the pullies when you try to bend and straighten your finger — it's often painful and can make a clicking sound. Sometimes the tendon can’t go through the pully and your finger is stuck in a bent position.

Trigger finger most often affects the thumb (trigger thumb), ring finger or little finger. Although it can affect any finger. It can also affect one or more fingers at a time and one or both hands. You’re more likely to get it in the hand you use most — as most people are right-handed, trigger finger is, therefore, more common in the right hand. 

Tendonitis and Dupuytren's contracture can also affect trigger finger. You may need surgery to correct trigger finger but sometimes it can go away by itself.

Trigger finger symptoms include:

• A lump at the base of your finger, on the palm-side
• Pain and tenderness when you flex — this is usually in the base of the finger or thumb
• Stiffness and clicking when you bend and flex a finger or thumb — likely to be worse when you wake up
• Your finger may become locked into a bent position and be difficult to straighten — the locked finger may then suddenly pop straight

Symptoms may be worse when you firmly grasp an object or straighten your finger. 

Your doctor can diagnose trigger finger through a physical examination and your medical history — no tests will be needed. They will ask you to open and close your hand, and will examine your hand for:

• Lumps on the palm — if a lump is due to trigger finger, it will move when your finger moves; this is because the lump is swelling in part of the tendon that moves your finger
• Tenderness
• Thickening or swelling
• Signs of locking and ‘triggering’ when you bend and straighten your finger
• Stiffness

What your doctor will need to know

When you see your GP, bring a list of the medications and supplements you regularly take. Your GP may ask you a series of questions about your symptoms including: 

• What are your symptoms? 
• How long have you had your symptoms? 
• Do your symptoms come and go or are they constant?
• Does anything make your symptoms better or worse?
• Are your symptoms worse in the morning or at any time of day?

They may also ask if you perform repetitive tasks for your work or hobbies and if you have recently had a hand injury. 

It is not known exactly what causes trigger finger, but it’s more common:

• If you have certain medical conditions, including carpal tunnel syndrome, diabetes and rheumatoid arthritis
• If you have Dupuytren's contracture —  the connective tissue in the palm of your hand thickens, which causes one or more fingers to bend into the palm
• If you're over 40
• If your work or hobbies involve repeated gripping 
• In women

It can often be caused if you put prolonged pressure on the palm of your hand, such as using a screwdriver.

Trigger finger is less common in children than adults but it does sometimes occur in children aged six months to three years. It can affect their ability to straighten their thumb but it usually goes away without treatment. It is not usually painful. 

If treatment is needed, this usually involves splinting and/or hand stretches.

In some cases, trigger finger doesn't need treatment and will get better by itself.

However, if it doesn’t improve, treatment is needed otherwise the finger or thumb may become permanently bent.

Treatment options include:

Physical treatments

• Resting your hand (and using painkillers)
• Stretching exercises to maintain your finger's range of movement
• Using a splint on the affected finger to rest it — this involves strapping your affected finger to a piece of rigid plastic to stop it moving; splinting overnight may help if your finger is particularly stiff in the mornings

Using a splint can help some people but there are other more effective treatments, such as medications and surgery. 

Medications

• Non-steroidal anti-inflammatory drugs (NSAIDs) eg ibuprofen or naproxen — these can reduce your pain but are unlikely to reduce the swelling of your tendon, which is causing it to get trapped in the sheath
• Steroid injections to reduce the swelling in the tendon — this is the most common medical treatment and is effective in 50-70% of people; its effects can be felt after a few days but it usually takes a few weeks and lasts for a year or more; you may need more than one steroid injection and injections can be less effective in people with diabetes or rheumatoid arthritis; side effects are rare but include infection and thinning or colour changes in the skin around the injection site
• Using painkillers (and resting your hand)

Surgery

If physical treatments and medications are not effective or are unsuitable, your doctor may recommend trigger finger surgery. This involves releasing the trapped tendon by cutting through the affected part of the sheath surrounding it.

Before recommending surgery, your doctor will consider factors including: 

• How much pain you are in
• How much trigger finger is affecting your life
• If your pain is linked to other medical conditions eg rheumatoid arthritis

Percutaneous release surgery

Percutaneous means 'through the skin'. This procedure involves your surgeon numbing the palm of your hand and then inserting a needle through your skin into the tissue around your affected tendon. Moving the needle and your finger will break up any tissue constricted around your tendon so it can move freely.  

Open trigger finger release surgery

An injection of local anaesthetic will be given into the palm of your hand to numb it. Your surgeon will make a small cut into your palm along a natural crease — this will make the scar less obvious. Next, they will cut through the tendon sheath to make it wider so your tendon can move freely. The cut will be closed, stitched and covered with a bandage.