Trigger Finger (Digitus saltans, Tendovaginitis stenosans)
Trigger finger is most commonly caused by degenerative thickening of the flexor tendon of the finger. The tendon is held onto the bone by ring-like series of ligaments called annular pulleys. The rings of the annular pulleys are normally wide enough to allow the tendon to slide freely along the bone during finger bending and extension. Thickening of the tendon makes passage through the narrow pulleys difficult. As a result, the tendon can get stuck under a pulley, and a large amount of force is needed to overcome the resistance. A popping sensation can be felt as the tendon snaps past a tight spot. Trigger finger occurs mainly in old age and predominantly affects women. The thumb, middle finger and ring finger are most commonly involved.
The diagnosis is usually obvious on clinical examination and no further diagnostic tests are needed. However, an X-ray may be obtained if needed for assessment of degenerative processes in the affected region.
If the symptoms are mild, cortisone can be injected directly into the tendon sheath as for first-line conservative treatment. Cortisone reduces inflammation.
If this fails to provide relief, surgical treatment can be considered. The surgery is performed under local anaesthesia. Surgical access to the area is obtained through a small skin incision. The ligament causing the tendon entrapment is then cut. After surgery, the finger does not have to be immobilised and can be used immediately.