Congenital trigger finger

Congenital trigger finger presents in the young child as a finger locked in flexion or extension. The finger can be fixed in one position - flexion or extension - or have a range of motion up to the point where the node impinges upon the pulley. Congenital trigger thumb is a much more common clinical variant of this problem and a similar acquired clinical condition is seen in adults - see submenu. Most cases are idiopathic but there is an association with obstetrical brachial plexus palsy.

A number of pathogenetic mechanisms have been suggested and the abnormal anatomy may not be as clearly defined as with congenital trigger thumb:

• excessively large tendon for size of surrounding sheath; indicated by a palpable and possibly tender Notta's node swelling at the level of the A1 pulley. Similar in aetiology to congenital trigger thumb
• a constriction or attachment between the flexor digitorum superficialis (FDS) and flexor digitorum profundus tendons that prevents their differential glide
• proximal decussation of the FDS tendon
• constriction at the level of pulleys within the digit (distal to A1)

If left, there is a risk of flexion contracture and as such, surgical treatment is generally favoured with release of the A1 pulley under general anaesthetic. The incision is either transverse within the digital crease or chevron-shaped. If A1 pulley release fails to resolve the restriction in movement, then other potential anatomical causes should be considered.