What is trigger finger?
Trigger finger, also known as stenosing tenosynovitis, is a painful condition that affects the tendons in the hand. When the finger or thumb is bent towards the palm, the tendon gets stuck and the finger clicks or locks.
Trigger finger can affect one or more fingers. The symptoms can include pain, stiffness, clicking and a small lump of tissue at the base of the affected finger or thumb (known as a nodule).
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What causes trigger finger?
Tendons are fibrous cords that join bone to muscle. They allow the bone to move when the muscle contracts. In the hand, tendons run down the bones in the fingers and are attached to the muscles in the forearm.
The tendons are held in place by strong bands of tissue, known as ligaments, which are shaped in arches over the tendon. These ligaments form a tunnel on the surface of the bone, which the tendons slide through. This tunnel is known as a tendon sheath.
Trigger finger occurs if there is a problem with the tendon or sheath, such as swelling, which means the tendon can no longer slide easily through the sheath. This makes it harder to bend the affected finger or thumb. If the tendon gets caught in the opening of the sheath, the finger can give a painful click, like a trigger being released, as it is straightened.
The cause of trigger finger is not known, but several things may increase the likelihood of it developing. For example, it is more common in:
- people who are over 40 years of age
- people with certain medical conditions
Conditions that can make trigger finger more likely include conditions that affect the hand, such as, although this is rare. They may also include some long-term conditions, such as diabetes. Around 10% of people with diabetes develop trigger finger.
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Treating trigger finger
In around 20–29% of people, trigger finger may get better without treatment. For other people, several treatment options are available, including
- Rest and medication – painkillers and non-steroidal anti-inflammatory drugs (NSAIDs) may be used to reduce swelling.
- Splinting – this involves strapping the affected finger to a plastic splint to relieve pain and aid recovery.
- Corticosteroid injections – steroids are medicines that may be used to reduce swelling.
- Surgery on the affected sheath – surgery involves releasing the affected sheath to allow the tendon to move freely again. This is a relatively minor procedure that is generally used when other treatments have failed. It can be up to 100% effective, although you will need to take two to four weeks off work to fully recover.
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If trigger finger is not treated, the affected finger could become permanently bent, which will make performing everyday tasks difficult.
Although most cases of trigger finger only affect one finger, it is possible for several fingers to be affected. If you have trigger finger in more than one finger the first time you notice a problem, you are three times more likely to have another finger affected in the future.
Trigger finger symptoms
Trigger finger usually affects your thumb, ring finger or little finger. More than one finger can be affected and the condition may develop on both hands. It is more common in the right hand, possibly because most people are right handed.
Symptoms of trigger finger can include:
- pain at the base of the affected finger or thumb (or both) when you move the finger or thumb, and if you press on the area
- a nodule (a small growth or lump of tissue) at the base of the affected finger or thumb
- stiffness or clicking when you move the affected finger or thumb, particularly first thing in the morning
If the condition gets worse, your finger may get stuck in a bent position and then suddenly pop straight. Eventually, it may not fully straighten.
Trigger finger in children
In a very small number of children between the ages of 18 months and three years old, trigger finger can affect the thumb. The main symptom will be an inability to fully straighten the thumb.
Causes of trigger finger
Trigger finger is caused by a problem in the tunnel that the tendon in your finger runs through (the tendon sheath). This makes it difficult for your tendon to slide through the tunnel and causes the pain and stiffness associated with trigger finger.
Problems with the tendon sheath
The most common problem involves one of the ligaments that make up the tendon sheath, usually the first ligament at the base of your finger. Because of its position, it is exposed to the most pressure in your hand, for example when you grip something. Over time, this ligament can become thicker than it should be.
As the ligament thickens, it partially blocks the opening of the sheath, making it harder for the tendon to slide in and out of the sheath.
When you bend your finger or thumb, the tendon slides down the sheath towards your arm. As you straighten your finger or thumb, the tendon should slide back up the sheath into your finger. If the sheath is partially blocked, the tendon cannot enter the sheath and your finger becomes temporarily stuck in a bent position.
The stuck tendon may suddenly pop past the swollen ligament into the sheath, releasing your finger like the release of a trigger.
Once the tendon in your finger starts getting stuck, the condition usually gets progressively worse. This can happen in one of three ways:
- The constant irritation or friction from the tendon getting stuck can cause the tendon to swell, making it harder for it to fit into the sheath.
- The irritation from the tendon can cause the lining of the sheath to become inflamed (swollen), making the sheath narrower.
- The irritation from the tendon can cause a small growth or lump of tissue (nodule) to form in the sheath, partially blocking it.
As the cycle of irritation repeats itself, the tendon eventually gets stuck and the finger becomes locked in a bent position. Sometimes, the tendon will pop free and your finger will be able to move again, but it may become stuck in a permanently bent position.
The cause of these problems is not fully understood and, in most cases, is never known. However, several things may make trigger finger more likely:
- Trigger finger is up to six times more common in women than men.
- It is more common in children under six years of age or in adults over 40, and is most common in people in their 50s or 60s.
- It is more common if you have injured the base of your finger or palm.
You may be more likely to develop trigger finger if you have any of the following conditions:
- diabetes – a long-term condition that is caused by too much glucose in the blood
- – a long-term condition caused by a problem with your immune system (the body’s defence system), resulting in pain and stiffness in your joints
- – a short-term condition that causes inflammation (swelling) in one or more of your joints
- – a condition where abnormal protein called amyloid builds up in organs, such as your liver
- – your body does not produce enough of certain hormones
- mucopolysaccharide storage disorders – a group of rare disorders that cause progressive physical and sometimes mental disability
- – a condition that affects the nerves in your wrist, causing pain and tingling
- – a condition that causes one or more fingers to bend into the palm of your hand
- De Quervain’s disease – a condition that affects the tendons in your thumb, causing pain in your wrist
Trigger finger treatment
The treatment of trigger finger depends on the severity of your symptoms and how long you have had them.
Some cases of trigger get better without treatment, so your doctor may recommend that you avoid activities that cause the pain to see whether this helps relieve your symptoms.(NSAIDs), such as , may help relieve the inflammation (swelling), as well as reducing the amount of pain.
Strapping your affected finger or thumb to a plastic splint may ease your symptoms. Splinting will stop your finger from moving, preventing the tendon from becoming irritated and reducing inflammation. This should help relieve the pain and any other symptoms you have.
If your finger is particularly stiff in the morning, it may help to use a splint overnight. Your doctor will tell you how long you need to wear the splint for. In some cases, it could be up to six weeks.
Using a splint is thought to be an effective treatment for around 50–70% of people.
Corticosteroids (steroids) are medicines that may be used to reduce swelling. Liquid corticosteroids are injected into the tendon sheath (the tunnel that the tendon slides through), at the base of your affected finger or thumb.
Corticosteroids are thought to work because they reduce swelling of the tendon. This allows the tendon to move freely again.
Corticosteroids are an effective treatment for 57–93% of people. They are most effective if:
- You have had your symptoms for less than six months.
- Only one of your fingers is affected.
- You do not have further complications, such as diabetes.
- You are having your first corticosteroid injection for trigger finger.
Serious side effects of corticosteroids are rare, but include:
- tendon rupture (when the tendon bursts)
- infection at the site of the injection
- dermal atrophy (where the skin or fat cells in your finger waste away)
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If the above treatments do not work, surgery is usually recommended. Surgery involves cutting through the thickened ligament that attaches the tendon to the bone in your finger, so that your tendon can move freely again.
Whether you have surgery will depend on how much pain you are in, whether it is associated with other medical problems, such as, and how much it is affecting your life.
In most cases, trigger finger is a nuisance rather than a serious condition. However, if it is not treated, the affected finger or thumb may become permanently stuck in a bent position or, less commonly, in a straightened position. This can make it difficult to carry out everyday tasks.
Surgery is 90–100% effective, although you will need to take some time off work and there can be complications (see below).
The operation takes around 20 minutes, and you will not need to stay in hospital overnight. The procedure is usually performed under, so you will be conscious but unable to feel any pain in your hand.
There are two types of surgery:
- open trigger finger release surgery
- percutaneous trigger finger release surgery
If you have rheumatoid arthritis, these types of surgery may not be recommended because they can cause your finger to drift sideways. Instead, a special procedure, called a tenosynovectomy, may be necessary. This involves removing part of the tendon sheath to allow the tendon to move again.
Open trigger finger release surgery
If you have open trigger finger release surgery, the surgeon will give you an injection of local anaesthetic into the palm of your hand.
A small incision (cut) is made in the palm of your hand along one of the natural creases, so that the scar will be less noticeable. The surgeon carefully cuts through the thickened ligament to release the tight opening of the tendon sheath. The wound will then be closed with stitches and covered with a light bandage.
Percutaneous trigger finger release surgery
Percutaneous means "through the skin". As with the open method of surgery, the surgeon will inject your hand with a local anaesthetic. However, instead of making an incision in your palm, a needle is inserted into the base of the affected finger. The needle will be used to slice through the ligament.
As percutaneous surgery does not involve an incision, you will not have a wound or scar. However, the procedure is slightly more dangerous than open surgery. Important nerves and arteries are very close to the tendon sheath and these can easily be damaged. For this reason, open surgery is usually the preferred method.
Recovering from surgery
After the procedure, you should be able to move your finger straightaway. The dressings can be removed after a few days to make movement easier, and full movement should return within a week or two.
If you have had open surgery, your palm may feel sore immediately after the procedure, but any discomfort should pass within two weeks.
- After surgery, you can start driving again as soon as you feel it is safe for you to drive.
- You may be able to write and use a computer immediately.
- You can play sports after around two weeks, once your wound has healed and you can grip again.
- When you can return to work will depend on your job. If you have a desk job or a job that involves light manual duties, you may not need any time off work. If your job involves heavy manual labour, you may need around three weeks off.
- If you have had surgery on more than one finger, your recovery period may be longer.
- If you have had percutaneous surgery rather than open trigger finger release surgery, your recovery period may be shorter, as you will not have a wound on your palm.
Caring for your wound
If you have had open surgery, your surgeon should tell you how to care for the wound in your palm. Washing it with mild soap and warm water is all that is usually required.
If you have stitches, you will be told if you need to return to hospital to have them removed. Some stitches are dissolvable and will disappear on their own in around three weeks.
You may be left with a smallrunning along your palm, where the incision was made.
If your finger was quite stiff before surgery, you may need specialised hand therapy after your operation to loosen it. Discuss this with your surgeon before the operation. The type of therapy may include:
- – manipulation, massage and exercise can help improve your range of movement.
- Occupational therapy – if you are struggling with everyday tasks and activities, either at work or at home, an occupational therapist will give you practical support to make those tasks easier.
Complications from surgery
Trigger finger release surgery is a safe procedure. However, as with any type of surgery, there are some risks. Complications are rare, but could include:
- stiffness in the finger
- pain in the finger
- nerve damage (if a nerve is damaged during surgery, you may never recover the full sensation in the affected area)
- tendon bowstringing, where the tendon is in the wrong position
- (CRPS), which causes pain and swelling in your hand after surgery – this usually resolves itself after a few months, but there can be permanent problems
There is a small chance that the surgery may not be successful or that your trigger finger returns. Trigger finger comes back after surgery in around 3% of cases.
Before your operation, ask your surgeon about the possible complications and risks.