Why Does My Finger Lock or Click? A Hand Surgeon Explains

It starts as a click. A finger bends into a fist and, on the way back out, hesitates for a moment and then jumps straight. Over the following weeks the hesitation lasts longer. Some mornings the finger is curled into the palm and has to be eased open with the other hand, and by mid-morning it is moving almost normally again. People describe it to hand surgeons in strikingly similar words: stuck, catching, locking, snapping, popping.

The classic explanation is trigger finger, a condition in which one of the tendons that bends the finger no longer glides smoothly through the tunnel that holds it in place. But clicking and locking are symptoms, not a diagnosis. Thickened tissue in the palm can pull a finger down so that it will not straighten. An arthritic knuckle can grind and stiffen. A tendon on the back of the hand can slip sideways over a knuckle after a blow. And plenty of fingers crack and pop with nothing wrong at all. Each of these has a different cause and a different treatment.

Nitin Goyal, MD, a hand, wrist and elbow surgeon at Midwest Orthopaedics at Rush, explains what is happening inside a finger that locks or clicks, how trigger finger differs from the conditions that can look like it, what treatment usually involves, and when a catching finger is worth an examination.

What Is Happening When a Finger Locks

The tendons that bend the fingers, the flexor tendons, are long cords that connect muscles in the forearm to the bones of the fingers and thumb. When those muscles contract, the tendons pull the fingers into a fist. Along the way, each tendon runs through a series of tunnels called pulleys that hold it close to the bone, a little like a fishing line running through the guides on a rod. The first of these, the A1 pulley, sits in the palm at the base of each finger and thumb.

In trigger finger, known medically as stenosing tenosynovitis, the tendon and that first pulley no longer fit each other. The tendon can thicken or develop a small bump, and the pulley can thicken and narrow, leaving less room for the tendon to pass. Instead of gliding, the tendon catches. When the finger bends deeply, the thickened part of the tendon squeezes through the pulley; when the finger tries to straighten, it catches at the edge of the pulley until enough force pulls it through and the finger snaps straight. That sudden release, like the pull of a trigger, gives the condition its name. When it involves the thumb, it is called trigger thumb.

In some cases the finger locks in a bent position and has to be straightened with the other hand, and in the most severe cases it cannot be straightened at all without a doctor's help. Less commonly, a finger locks straight and will not bend.

According to the American Academy of Orthopaedic Surgeons (AAOS), trigger finger affects about 2% of the general population. It can involve one finger or several, in one hand or both, and any finger or the thumb can be affected. Most cases have no clear cause, and symptoms often begin without any change in activity. It is more common in women between 40 and 60, in people with diabetes, rheumatoid arthritis or amyloidosis, and in people whose work or hobbies involve repetitive gripping or pinching. Cleveland Clinic also lists gout, thyroid disease and osteoarthritis among the conditions that raise the risk.

The Signs That Point to Trigger Finger

Trigger finger usually starts slowly and gets worse over time. The pattern that hand surgeons listen for has several parts:

• A catching, popping or locking sensation as the finger or thumb bends or straightens
• A tender lump in the palm at the base of the finger or thumb
• Pain at the base of the finger when it bends or straightens, which can travel up into the finger or down into the palm
• A finger that gets stuck bent and has to be helped straight
• Stiffness and locking that are worst after rest, especially on waking, and that ease with gentle use through the day

One detail surprises many people: although it is the finger that sticks, the problem, and usually the tender spot, is in the palm, at the base of the finger where the A1 pulley sits. A click or catch that seems to come from the back of the hand, or from a knuckle joint itself, raises the possibility of something else.

Other Reasons a Finger Clicks, Catches or Will Not Straighten

Several other conditions produce a finger that clicks, sticks, or stays bent. Some of them share the same lump in the palm or the same morning stiffness, which is why the distinction is made by examination rather than by the symptom alone.

Dupuytren's contracture

Dupuytren's disease affects the palmar fascia, the fibrous layer of tissue under the skin of the palm. In people who have it, the fascia gradually thickens and shortens. It usually shows up first as small, firm nodules in the palm that are fixed to the skin, sometimes with dimples or pits in the skin nearby. Over time the nodules can form thick cords that pull one or more fingers toward the palm, making them difficult or impossible to straighten fully. The cords can look like tendons, but the tendons themselves are not involved.

AAOS describes Dupuytren's disease as typically progressing very slowly, over years. The ring and little fingers are the ones most commonly affected, and the knuckle where the finger meets the hand is the joint most often drawn down. The nodules may be tender at first, but the tenderness usually fades. It is more common in men, in people of northern European and Scandinavian ancestry, in people with a family history of the condition, and in people with diabetes. The difference that tends to stand out from trigger finger is the movement: a finger with Dupuytren's contracture is gradually drawn down and stays down, rather than catching and then releasing.

Arthritis in a finger joint

Arthritis in the small joints of the fingers can also make a finger feel as though it is catching. According to AAOS, arthritis of the hand can produce a grating or grinding sensation or sound in the joint, called crepitus, along with a dull or burning pain that often follows heavy use, morning pain and stiffness, swelling, and in some cases a joint that looks larger than normal. When arthritis affects the joints nearest the fingertips, small cysts can form there. The location is the clue: arthritis grinds and aches at the knuckle joint itself, while trigger finger catches at the base of the finger in the palm. At the base of the thumb the two are easily confused, because both can leave a sore spot there and both can sit behind thumb pain when gripping.

A tendon slipping over a knuckle

The tendon that straightens each finger runs over the back of the knuckle where the finger meets the hand, held in the center of the joint by bands of tissue called sagittal bands. A direct blow to that knuckle, such as a punch, can injure those bands, an injury sometimes called "boxer's knuckle." The tendon can then slip off to one side of the knuckle as the hand makes a fist, causing a snap as the finger bends and straightens, and over time the finger can become hard to straighten at that knuckle. Because it also snaps as the finger moves, this injury is commonly mistaken for trigger finger. The differences are where the snap happens, on the back of the hand over the knuckle rather than in the palm, and the injury that usually came before it.

A finger that will not straighten after an injury

A fingertip that droops, or a middle knuckle that will not fully straighten after a ball or a fall strikes the finger, is not a trigger finger. Those patterns point to an injury of one of the tendons that straighten the finger, such as a mallet finger or a central slip injury, and they are among the injuries that can hide behind what looks like a jammed finger. Tendon injuries like these tend to do better when they are treated early, so a finger that stopped straightening after an injury is worth prompt attention.

A thumb that stays bent in a young child

Trigger finger is rare in children, but a condition called congenital or pediatric trigger thumb can leave a child's thumb locked in a bent position at the end joint. In children, a trigger thumb is more common than a trigger finger. It is a separate condition from adult trigger finger, with its own approach to treatment, and a young child's thumb that will not straighten should be evaluated by a specialist.

Painless cracking and popping

Many people can crack their knuckles, and some fingers pop now and then on their own. The familiar crack of a knuckle is thought to come from gas bubbles in the joint fluid as the space within the joint briefly widens. Harvard Health Publishing notes that in the absence of pain, swelling or other joint symptoms, these sounds are probably nothing to be concerned about, and a 1990 study it cites found that arthritis was no more common in habitual knuckle crackers than in people who did not crack their knuckles. A click that comes with catching, a tender lump, pain, or a finger that gets stuck is a different matter.

Locking, Clicking or Bent Fingers, Side by Side

What People Commonly Try First

For a finger that clicks or catches but still moves, the measures a clinician typically recommends first for trigger finger are simple ones: a break from the repetitive gripping or pinching that aggravates it, a splint worn at night to hold the finger straight while you sleep, an over-the-counter anti-inflammatory if it is appropriate for your health history, and gentle stretching exercises from your provider to ease stiffness. Many people have already tried some of these by the time they see a hand surgeon, and that is a reasonable place to start.

The same measures are not necessarily the right ones for the conditions that resemble trigger finger, and a finger that stopped straightening after an injury needs a diagnosis before it needs a splint. That is one reason a catching finger that is not settling is worth an examination rather than more weeks of guessing.

How Trigger Finger Is Diagnosed and Treated

A hand surgeon can usually diagnose trigger finger by asking about the symptoms and examining the hand. The examination looks for tenderness over the tendon sheath in the palm, thickening or swelling at the base of the finger or thumb, and a click or catch as the finger bends and straightens. According to AAOS, X-rays or other tests are typically not needed to diagnose trigger finger, although a provider may sometimes use an ultrasound or X-ray.

Injection

Another first-line option is a corticosteroid injection near the A1 pulley, given in the office. AAOS notes that in many cases the injection can resolve the condition, and that if symptoms do not improve, or improve and then return, another injection may be given. Cleveland Clinic notes that injections usually take a few weeks to relieve symptoms. Injections are less likely to work, though they may still help, in people with diabetes, in people who have had triggering for a long time, and in trigger thumbs. In people with diabetes who take insulin, the steroid typically raises blood sugar for about 10 to 14 days, so blood sugar needs to be monitored closely after an injection.

Trigger finger release

When symptoms are severe, when they do not improve with other treatment, or when the finger is stuck bent and cannot be straightened, a surgeon may recommend trigger finger release. It is an outpatient procedure, so you go home the same day. The area is numbed with an injection, and you can be awake or lightly sedated. Through a small cut in the palm, or with the tip of a needle, the surgeon opens the A1 pulley to give the tendon room to glide. Opening that pulley does not hurt hand function as long as the other pulleys are left in place. Occasionally, in people who have had triggering for a long time, part of the tendon also needs to be removed.

As with any operation, there are risks, which the surgeon will discuss beforehand; AAOS describes complications as rare but lists infection, stiffness and return of symptoms among them. Most patients are told to start moving their fingers right after surgery. AAOS notes that the incision usually heals within a few weeks, but that it may take 4 to 6 months for swelling and stiffness to go away completely. A finger that was locked bent for a long time before surgery may need a course of work with a hand therapist afterward to regain full straightening.

The timing of trigger finger surgery depends on the person. For people with diabetes, or with several fingers involved, injections may not last as long, and the conversation about surgery may come sooner. Which approach fits, and whether any procedure is needed at all, is a decision made with the surgeon after the examination.

When to Have a Locking or Clicking Finger Checked

A finger that clicks now and then without pain, swelling or catching rarely needs an appointment. These are reasons to be seen:

• A finger or thumb that is locked bent and will not straighten, or straightens only with force
• Catching or locking that keeps coming back or is getting worse over weeks
• A tender lump in the palm at the base of a finger, with pain when the finger bends or straightens
• A finger that is slowly being drawn toward the palm and will not fully straighten
• Clicking with pain, swelling or grinding at a knuckle joint
• A snap over the back of a knuckle after a blow to the hand
• A finger that stopped straightening after an injury
• A young child's thumb that stays bent
• Catching in more than one finger, especially if you have diabetes

Cleveland Clinic advises going to an emergency room if you suddenly cannot move or use a finger or thumb. For a finger that is locked bent, it is worth arranging a visit promptly rather than waiting it out, because the longer a finger stays locked, the more stiffness can develop around it.

Frequently Asked Questions

Why does my finger lock in the morning?

In trigger finger, stiffness and locking tend to be worse after a period of inactivity, which is why they are often at their worst on waking. They usually ease through the day with gentle use of the hand. Morning stiffness is also common with arthritis, so the timing alone does not settle the cause.

Is it a problem if my finger clicks but does not hurt?

Not necessarily. Painless cracking and popping without swelling or other joint symptoms is probably nothing to be concerned about. A click that comes with catching, a tender lump in the palm, pain at the base of the finger, or a finger that gets stuck is different, and it is worth having examined.

Can trigger finger affect more than one finger?

Yes. Trigger finger can occur in one finger or several, and in one or both hands. Cleveland Clinic reports that about one in three people with trigger finger have it in more than one finger at a time. People with diabetes can be more likely to have several fingers involved.

Is trigger finger the same as Dupuytren's contracture?

No. Both can cause a lump in the palm and a finger that is bent, but they involve different tissues. Trigger finger is a problem with a flexor tendon and its pulley, and the finger typically catches and then releases. Dupuytren's contracture is a thickening of the fascia under the skin of the palm, and the tendons are not involved; the finger is gradually pulled toward the palm and stays there.

Can carpal tunnel syndrome cause trigger finger?

They are separate conditions, but they can occur together. Carpal tunnel syndrome is listed among the conditions associated with trigger finger in adults. Numbness and tingling in the fingers point toward a nerve problem such as carpal tunnel syndrome; catching and locking point toward the tendon. Some people have both, which is one reason a hand surgeon examines the whole hand.

Do I need an X-ray for trigger finger?

Usually not. Trigger finger is typically diagnosed from the history and the examination, although a provider may sometimes use an X-ray or ultrasound. Arthritis in a finger joint, by contrast, is diagnosed by examination and X-rays, so an X-ray is more likely when arthritis is part of the picture.

The details of a clicking finger tell a hand surgeon a great deal: where the catch is felt, whether the finger releases or stays down, whether it began with an injury, and how it behaves first thing in the morning. A finger that locks, catches repeatedly or no longer straightens is one the hand and wrist specialists at Midwest Orthopaedics at Rush would rather examine early, while the simplest options are still on the table.

This article is for general information and is not a substitute for medical advice. Please consult a physician about your individual situation.

Header image: "Trigger finger - right middle finger" by RCraig09, via Wikimedia Commons, CC BY-SA 4.0, cropped.

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A finger that catches, locks or will not straighten deserves a closer look. Our fellowship-trained hand, wrist and elbow surgeons evaluate and treat trigger finger and the conditions that resemble it, and the first job is finding out which one you are dealing with.