In Western films it is not unusual that when the trigger is pulled against the hero, a fire does not follow, and the crowd cheers that part of the mechanics inside the firearm got stuck. This is similar to what happens with trigger finger: one’s finger is stuck bending and cannot be smoothly straightened.
When we move our finger, the muscle pulls the bone via the tendon, a fibrous cord connecting the muscle to the bone. While we move our finger numerous times a day, we don’t have to worry the wear and tear of the tendon, because it is surrounded by a sheath and protected from abrasion. However, if the sheath narrows down by inflammation or other tissue changes, the tendon can be trapped so that we cannot pull the trigger, our finger, freely.
Trigger finger can happen spontaneously. Some jobs like operators of concrete vibrators and farmers, or some hobbies like gardening and bowling, require repetitive, prolonged, or strenuous gripping and may increase the risk. Women at the age of 40 to 60, and patients with diabetes, rheumatoid arthritis, etc., are more susceptible to trigger finger. It is also one of the complications from the surgery to treat carpal tunnel syndrome, especially within the first 6 months.
Symptoms can start with morning stiffness of the affected finger, along with some popping movements. In the cases that the sheath grows too thick, a bump can be felt on the palm, most often at the finger base. It would be wise to see a doctor if the finger is locked in a bent position, with numbness, or the joint feels hot, painful, and inflamed. Trigger finger can usually be diagnosed with history and some specific physical exams of the hand. Imaging is generally not required.
Conservative therapies are the mainstays to manage trigger finger. Rest the affected finger if possible, or use padded gloves for protection. A splint to keep the finger straight for up to 6 weeks facilitates the rest. Exercise of stretching the finger gently may also help. Meanwhile, over-the-counter medications such as ibuprofen and naproxen can be used to control the pain for a short term (less than 2-4 weeks). Although they belong to the family of nonsteroidal anti-inflammatory drugs, studies have found that they improve little of the inflammation. Instead, a corticosteroid injection is effective in reducing the swelling and allowing the tendon to slide smoothly within the sheath again, and the relief can last for one year in some patients. Unfortunately, patients with diabetes are reported not responding to steroid injection as well as others.
Surgical procedures can be considered if conservative treatments fail. In the office, a doctor can numb the finger, use ultrasound to guide a needle through the skin, and break the narrow part of the tendon sheath. Alternatively, a hand surgeon can cut open the constriction in the operating room, and provide immediate release of the tendon. Recurrence of symptoms happens in around 5% of patient from 6-12 months after an open surgery. In contrast, the recurrence rate can be up to 40% after corticosteroid injection.
So, if your finger gets stuck see your doctor who can work on the mechanics and free it.