A trigger thumb, or finger, occurs due to thickening of the flexor tendon to the thumb at the level of the A1 pulley on the palmar surface of the hand. This is approximately at the level of the metacarpo-phalangeal joint (MCP). There is usually a palpable thickening, termed Notta’s node, at this location which you or the parents can easily feel.
This is a clinical diagnosis and made when the parents notice that their child cannot straighten the thumb all the way. The involved thumb is “bent” at the interphalangeal joint of the thumb. Occasionally the child may be able to straighten the thumb after some time but feels a pop or click when this happens.
This is often worrying to parents, and although it affects the child’s ability to straighten their thumb, it is rarely painful, causes no functional problems and often gets better without any treatment. Occasionally it may be painful for a week or so but it usually passes quickly.
Many trigger thumbs in children resolve spontaneously with no treatment although this may take a year or so. There is no evidence that splintage or exercises make any difference to this.
There for the vast majority we pass on our reassurance that it is quite safe to simply observe this and hope that the triggering settles down over time.
Referral is usually only necessary if any of the following are present:
- Age over 3
- History of fixed deformity over 12 months
- Uncertain diagnosis
- Unable to relieve parental concerns.