Trigger Finger Treatment & Surgery

What is Trigger Finger?

Trigger Finger is a very common cause of pain and stiffness in the fingers.

The tendons that flex or bend the fingers become stuck in the palm, at the entrance to a tunnel called the flexor sheath that goes into the finger. This tunnel keeps the tendons close to the bone when the finger flexes, helping them flex the finger more effectively. In trigger finger, the entrance to the tunnel, called the A1 pulley, becomes thickened and narrowed, restricting the tendon movement. The friction of the tendon rubbing against the narrowed A1 pulley each time it passes through makes it become more swollen and stiffer and makes its movement painful.

This happens when there is swelling and narrowing of the tendon sheath in the palm (the hood anchoring the flexor tendons to the bone), causing constriction of the flexor tendon at the entrance of the sheath. A nodule forms when the tendon fibres bunch up at the entrance and when the tendon is finally force through, it “triggers”.

Each of the fingers and the thumb have a flexor sheath and may be affected by trigger finger.

How Do I Know I Have it?

In the early stages, you may just have some pain in the palm and a bit more difficulty flexing and extending the affected finger. Most people will ignore this and carry on with their activities as normal.

In the next stage, you will notice that the finger “jams” or “catches” when you try to extend it from a fully flexed position. This is called “triggering” as it is similar to when the trigger of a gun is pulled, it has some resistance initially and then suddenly moves freely after it passes the catch. The finger can still extend fully after it has overcome this resistance. This is often painful but not always. Sometimes you may wake up with the finger stuck in flexion and needing to be pulled straight. The finger movement improves after doing some exercises to loosen your hand, after which it may be fine for the rest of the day.

Eventually, everything becomes so stuck that the finger cannot bend fully without using a lot of force, and once it does, it becomes stuck in flexion and cannot be extended without being pulled straight using the other hand. It is usually very painful when this happens.

If you leave the finger stuck in flexion for too long, it becomes impossible to straighten it even with the other hand. This is the final stage of trigger finger.

What Causes Trigger Finger?

There is no single cause, and most cases are a result of accumulated wear and tear and overusage of the hand. The middle, ring and thumb are commonly affected. Trigger finger in most people is a repetitive strain injury. It is caused by frequent gripping, for example when doing weight training, playing golf or tennis or other racquet games, carrying heavy shopping bags, and doing housework with a lot of wringing and scrubbing. Driving for long hours every day can also cause it, and it is quite common amongst drivers. You may not associate it with these activities, because the thickening builds up slowly over time and is not noticeable until it is bad enough.

Usually this takes years or decades. It is most common in people between 40-60 years of age. Symptoms are often worse in the morning and improves as the day progresses. Diagnosis is by history and physical examination.

People with diabetes, kidney problems or thyroid problems, have increased risk of getting trigger finger, as these conditions make the tendons and flexor sheath stiffer.

How is Trigger Finger Treated?

Conservative Treatment

If it is mild or early (within a few weeks), trigger finger can be treated by resting the finger in a splint, anti-inflammatory medication, and gentle exercises to free the tendons. Ultrasound or laser therapy by a certified hand occupational therapist can also help. You need to rest and avoid activities requiring any strong gripping for at least 2-3 months.

Steroid Injections

If it has been present for more than a month, or you are no longer able to flex the finger or the finger gets stuck when flexed, then a steroid injection is needed. A small amount of steroid is injected with a very fine needle around the A1 pulley in the palm. This reverses the changes in the pulley and tendon, making them softer and looser. The finger usually goes back to normal within 1-2 weeks of the injection. The triggering takes a few days to resolve after the injection and is curative for 50% of the cases. If you do not want to wait 2-3 months for it to recover with rest and therapy, this is also a very good option for mild or early trigger finger.

If it recurs, a second injection can be repeated. Steroid injection needs to be done with aseptic technique because it is important to prevent infections with steroid injections.

Risks of steroid injection for trigger finger are very rare. These include infection, increased pain and swelling for a day or two after injection (steroid flare reaction) and thinning of the skin. It is extremely rare to have tendon ruptures.

Surgery

Unfortunately, whether with rest and therapy or steroid injections, 30-50% of patients who recover from trigger finger will experience it again in the same finger within 3-6 months of recovery. This is because the changes in the tendon and A1 pulley may not have reversed completely and returning to the same activities will cause them to thicken and tighten once again.

If it comes back, or if it is so bad that the finger cannot straighten any more, then surgery is the best option. This is a minimally invasive, 10-minute procedure done under local anaesthesia either in the clinic or hospital as a day surgery. Through a tiny cut hidden in a line in the palm, the A1 pulley is cut open, freeing the tendons. The incision is then stitched up with one or two stitches that do not need to be removed. The wound heals in one week, and finger movement returns to normal over 1-4 weeks. There are typically no visible scars, and the condition never comes back again in the operated finger.

While surgery is necessary for those who have failed rest and therapy or steroid injections, it is also an excellent and simple solution for those at any stage who want a fast and permanent solution instead of going through either prolonged therapy or an injection, only to risk it recurring after a few months.

Surgery is curative for recurrent cases. The aim of surgery is to release the thickened sheath, allowing the tendon to glide freely during bending and straightening the finger. The affected digits should recover normal function after surgery. Therapy is needed for patients with advanced triggering with finger joints contracted. This can take 3 months to straighten out the joint. Early treatment gives the best results.

Risks of surgery are minimal when done by experts. These include infections (<0.001%) and pain or stiffness requiring more than a month to go away (5%). Those with diabetes or kidney problems have a slightly higher risk but in general do just as well as those without.

How Do I Prevent it?

The only way to prevent trigger finger is to avoid or minimise activities requiring frequent or strong gripping, especially with impact to the palms. This means avoiding many types of sports and gym exercises, wringing, or squeezing actions, and carrying heavy bags in the hand. Those with diabetes should optimise their long-term blood sugar control to prevent stiffening of the tendons and sheath.

How To Manage Trigger Finger Symptoms?

video source: 96.3好FM
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