Congenital trigger thumb is a pediatric condition which
results in flexion deformity of the thumb at the IP joint. There will be
triggering and flexion deformity of the IP joint of the thumb and a nodule can
be felt at the base of the thumb over the MCP joint of the thumb. The condition
can be developmental or congenital. Congenital trigger thumb is bilateral in
25% of cases. The flexor pollicis longus tendon is thickened and its diameter
is increased compared to the A1 pulley. Thickening of the tendon will interfere
with normal gliding of the tendon and will cause some triggering which can lead
to fixed contracture of the thumb. Spontaneous resolution of the symptoms is
unlikely after the age of 2 years. It is a flexion deformity at the thumb IP
joint. The flexor tendon may have a nodule called “Nota’s Node”. The patient
may not be able to extend the IP joint due to fixed flexion deformity. X-rays
are usually normal. Treatment is extension splitting in the first year. If the
patient is less than one year of age, the treatment is observation, stretching,
and splinting. Do passive extension exercises with intermittent extension
splinting. There will be about 50% resolution of symptoms. Surgery is done if
there is failure of conservation treatment or if there is fixed deformity after
1 year of age. If there is no spontaneous correction of the deformity by 1
year, do release of the A1 pulley. During the A1 pulley release surgery, you
must protect the radial digital nerve which may cross the field. Avoid release of
the oblique pulley because this may lead to bowstringing of the flexor tendon.
Usually multiple fingers are affected. There will be distal triggering as the
flexor digitorum profundus passes through the sublimus decussation at the level
of the A2 pulley (not the A1 pulley). Treatment is usually excision of one
sublimus slip to allow for smooth gliding of the FDP tendon.
