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 which help the tendons to glide smoothly. These sheaths are attached to the inside of 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

It most often affects the thumb, ring finger or little finger of either – or both – hands. You’re more likely to get it in the hand you use most.

Tendonitis can also affect trigger finger, as well as dupuytren's contracture. You may need surgery to correct trigger finger, but sometimes it can go away by itself.

Trigger finger symptoms include:

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

Your doctor will discuss your symptoms with you and examine your hand for:

• Tenderness
• Thickening or swelling
• Stiffness
• Signs of locking and ‘triggering’ when you bend and straighten your finger

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

• In women
• If you're over 40
• If you have certain medical conditions, including carpal tunnel syndrome, diabetes and rheumatoid arthritis

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

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:

• Resting the hand and using painkillers
• Using a splint on the affected finger to rest it
• Steroid injections to reduce the swelling in the tendon
• Trigger finger surgery to remove the sheath - your doctor may advise this if other treatments haven’t worked