Sometimes, it is locked in acute flexion and cannot be extended. Trigger thumb is due to thickening and constriction of the fibrous flexor sheath the surrounds the Flexor pollicis tendon at the base of the thumb. The constriction does not allow for free movement of the tendon within the sheath. This causes the thumb to be stuck in the flexed position. The condition may present at birth, or during infancy.
Treatment is often conservative.
Parents are taught to stretch the thumb and gently extend the thumb, even in the thumb that is locked in flexion. Over a period of 18 to 24 months, the triggering may resolve spontaneously. In cases where the thumb is locked in acute flexion and does not allow any extension, surgical release of the fibrous flexor sheath is indicated by age 2 to prevent permanent contracture. The information presented is for your information only, and not a substitute for the medical advice of a qualified physician. Neither the author nor the publisher will be responsible for any harm or injury resulting from interpretations of the materials in this article.