You reach over to straighten your toddler’s thumb and it won’t move. Or it goes straight with a small click, like a hinge popping loose, then springs back. The thumb sits bent at the top joint, and it may have been that way for weeks before anyone noticed. This is trigger thumb, more common in small children than most parents realise, and in most cases it settles without surgery.
What follows is what causes it, how it’s treated in Singapore, and when a hand surgeon gets involved.
Trigger thumb is a thumb stuck or clicking in a bent position, caused by a swelling on the tendon called a Notta node. It usually appears between one and three years old, doesn’t hurt much, and often resolves with time or splinting.
Surgery is a small day procedure, considered only when the thumb stays locked and affects how the child uses the hand.
What trigger thumb is
The tendon that bends the thumb runs through a narrow tunnel of tissue. In trigger thumb, a small lump forms on the tendon, and the lump catches at the entrance to the tunnel, like a knot trying to pass through a too-tight loop. The result is a thumb that clicks as it passes, or gets stuck bent and won’t straighten on its own.
The lump is called a Notta node, and you can often feel it as a small firm bump at the base of the thumb on the palm side. Dr Anthony Foo, a hand surgeon at the National University Hospital, has explained that whether the node is present from birth or develops afterwards isn’t fully clear, because parents usually only notice the bent thumb months later, once the baby is using the hands more. Newborn hand and mouth behaviours like the rooting reflex in babies announce themselves in the first days; a stiff thumb hides in plain sight until the grabbing starts.
How to spot it
- The thumb is held bent at the top joint and is hard to straighten
- It clicks, catches or pops when it does straighten
- You can straighten it by pulling with your other hand, but it springs back
- The child can’t straighten it using their own thumb muscles
- There’s a small firm bump at the base of the thumb
It usually shows up between one and three years old. It can affect one thumb or both. Other fingers can develop the same problem, but in children the thumb is by far the most common.
Does it hurt?
Usually not. Children with trigger thumb tend to carry on as normal, and parents often say it doesn’t seem to bother the child at all, though it can hurt if someone forces it straight. Because children adapt and use their other fingers, a stuck thumb doesn’t necessarily limit what they can do, which is part of why it’s often noticed late. Quiet conditions get spotted slowly, the way puffy eyes from nephrotic syndrome in children can be written off as a bad night’s sleep for weeks.
How common it is
NUH’s Hand Centre has estimated the rate at about 15 in 1,000 children seen, so it’s not rare. Doctors also note that a good number of cases in the youngest children settle on their own before treatment is needed.
Treatment in Singapore
Watching and waiting
In very young children the thumb often improves without any treatment, so a doctor may simply review it over time. This is a reasonable first step when the child is still an infant.
Splinting and stretching
Dr Foo has described splinting as the mainstay of treatment, with up to half of children recovering within a year or two. A splint holds the thumb straight, usually at night, to stretch the tendon through its tunnel. Gentle stretching exercises may be shown by a hand therapist. This is the standard non-surgical route.
Surgery
Surgery is considered when splinting hasn’t worked, the thumb is constantly locked, and the child’s hand use is clearly affected. The operation, called an A1 pulley release, is a small day procedure done under general anaesthetic: the surgeon makes a tiny cut at the base of the thumb and opens the tight part of the tunnel so the tendon glides freely. Recovery is quick.
On timing, Dr Foo has said the decision weighs the child’s age, the size of the thumb and their developmental milestones, and that many hand surgeons prefer to operate before the child starts preschool, so a visibly different thumb doesn’t become something they’re self-conscious about among classmates.
When to see a doctor
Any thumb or finger that stays bent, clicks or won’t straighten is worth having checked. Your GP or paediatrician can refer you to a hand surgeon, and in Singapore the hand centres at NUH, SGH and KKH all see children. This one sits on the non-urgent list, unlike the risks that need fixing the same day, window and fall safety at home being the obvious example. Still, an assessment settles whether to watch, splint or plan surgery, and takes the guesswork out of it.
Common questions
What causes trigger thumb in children?
A small swelling on the thumb’s flexor tendon, called a Notta node, catches as it passes through a narrow tunnel of tissue, so the thumb clicks or locks in a bent position. Whether it’s present at birth or develops later isn’t fully clear.
Does trigger thumb go away on its own?
Often, especially in very young children. Splinting helps up to half of children recover within a year or two, and surgery is reserved for thumbs that stay locked and affect hand use.
Is trigger thumb painful for a child?
Usually not. Most children aren’t bothered by it and adapt using their other fingers, though forcing the thumb straight can hurt.
At what age does trigger thumb appear?
Most commonly between one and three years old, often noticed once a child is using their hands more.
What’s the surgery for trigger thumb?
An A1 pulley release, a small day surgery under general anaesthetic in which the surgeon opens the tight part of the tendon tunnel through a tiny cut at the base of the thumb. Recovery is quick.
Where can I get trigger thumb treated in Singapore?
The hand surgery centres at NUH, SGH and KKH all treat children. Ask your GP or paediatrician for a referral.
Getting that thumb looked at
A bent, clicking thumb in a toddler rarely hurts, and time or a night splint sorts out plenty of them. Book the referral anyway, because knowing which path you’re on beats stretching the thumb yourself every evening and hoping. And if it comes to surgery, it’s a quick day procedure, usually done before preschool starts, well before your child is old enough to wonder why their thumb looks different from everyone else’s.
More on children’s health
- Mummy thumb: the wrist pain new parents get, and exercises for it
- Newborn reflexes every new parent should know
- Hidden hand hazards at home
Clinical detail is from Dr Anthony Foo of the National University Hospital Hand and Reconstructive Microsurgery Centre, as told to theAsianparent, with general treatment information from Seattle Children’s Hospital. Your child’s own doctor’s assessment takes precedence.