Stenosing tenosynovitis, commonly known as trigger thumb, is a condition in which the thumb becomes locked in a bent position. Due to irregularities of the underlying tendon, a child with stenosing tenosynovitis has difficulty extending the thumb and may experience pain after doing so. Trigger thumb can appear as early as infancy and accounts for 2 percent of hand complications in children, according to the Children's Hospital of Boston.
Description
Tenosynovitis constricts the motion of the finger, causing the joint to lock in place when the thumb is bent. Although tenosynovitis can appear in other fingers, it typically affects the thumb in children. When the child attempts to straighten the digit, the thumb catches or snaps before extending. In most cases, stenosing tenosynovitis is accompanied by pain and soreness, as well as the gradual formation of a node at the base of the thumb, says the Mayo Clinic. Without treatment, a trigger thumb can become fixed in the flexed position, making it difficult for the child to hold objects properly.
Causes
Placing frequent strain on the tendons can cause tenosynovitis in adults, but trigger thumb is often considered to be a congenital condition when it appears in children. In a healthy thumb, the flexor tendon connects the muscles to the bone, creating movement in the hand as it glides through a sheath known as the A1 pulley. Stenosing tenosynovitis occurs when the sheath is swollen or too small to allow smooth movement of the flexor tendon. Repeated friction between the tendon and the sheath eventually leads to inflammation.
Diagnosis
Parents should consult a physician for treatment before the joint becomes permanently locked, when the child experiences stiffness or inflammation. Trigger thumb is diagnosed through observation and a review of the patient's medical history, rather than an X-ray. The physician performs a physical examination to observe pain and the degree to which the thumb's movement is restricted. In some cases, the condition is resolved on its own, but the likelihood of spontaneous resolution decreases as the child gets older, says the Children's Hospital of Boston. Surgical release of the A1 pulley is commonly recommended for children over 1 year old.
Surgical Treatment
Surgery for trigger thumb is an outpatient procedure involving the loosening of the A1 pulley. The surgeon administers anesthesia, and then makes an incision between the base of the thumb and the palm. A cut is made in the sheath around the flexor tendon to allow the unhindered movement of the tendon. Once the sheath is cut, new cells grow in between the damaged areas during the healing process, making the A1 pulley wider after it heals.
After the Surgery
Factors such as inadequate release of the tendon sheath can cause recurrent trigger after the surgery, but such complications are rare. Following the procedure, the hand is sutured and wrapped in a bulky soft bandage for at least 1 week. The child should limit activities performed with the hand for a few weeks to allow full recovery. The stitches are typically removed two weeks after the surgery and parents can continue to dress the wound at home until the physician gives permission to leave the thumb uncovered.
