Trigger thumb is a condition that causes your thumb get stuck in a bent (flexed) position. Trigger Thumb generally results from inflammation within a tendon sheath, restricting tendon motion. A bump (nodule) in the tendon also may form. Tendons work to make our thumbs move. They are like strings inside your thumb and are held in place by a tunnel system of ligaments (also known as “pulleys”). These tunnels or ligaments keep the tendon next to the bone and allow it to slide back and forth.
The flexed fixed deformity of the affected thumb causes difficulty with passive extension and this can cause painful triggering or snapping . Pathological findings of this condition are fusiform hypertrophy of the flexor pollicis longus (FPL) tendon producing a nodularity of the FPL tendon ( “Notta’s node”), palmar to the metacarpo-phalangeal (MP) joint, and flexion deformity at the thumb interphalangeal (IP) joint.
Incidence of Trigger thumb is 3 /1000 live birth, mostly in between age 1 and 3. Most often, it occurs in children at about age 2. Boys and girls have the same risk of developing Trigger thumb. Both thumbs can be affected in up to 30 percent of children and spontaneous improvement in 30% of cases.
Cause - The exact cause is not known. Children are not born with it. It does not occur from overuse, trauma, or injury.
Right trigger thumb with Flexion deformity at IP Joint
(1) Wait and watch to see if the flexion contracture goes away on its own. In children younger than one year of age, sometimes disappears without anything being done. Observation for spontaneous resolution up to the age of 12 months.
(2) Stretching and splinting the thumb - the thumb will be kept straight in a splint. child may need to wear the splint at all times or at specific times, such as when sleeping. Keeping the thumb in a straight position, without allowing movement, can help the swelling go down. Stretching and splinting are not always successful. Movement may be improved but full motion may not be achieved.
Surgery is done in an Day care procedure and has few risks. The surgery will be a small cut or incision at the base of the thumb at MCP Joint. The A1 pulley ligament is release either Open or percutaneous USG Guided procedure.
Post operative protocal – An extensor-type splint ( 10 cc Cut Syringe ) was used for immobilization at day /night time in all children’s for 15 days . Active and passive exercise was started at 1 week after surgery.
Case 1 – 3-year female child with deformity of thumb as Right Trigger thumb
