TRIGGER FINGER
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What is a Trigger Finger?
A Trigger Finger is described as the catching or locking of a finger in a bent (flexed) position. Its very common. About 3% of people will experience this condition at some point in their life.
Trigger finger is caused by inflammation that prevents the tendon from gliding smoothly.
Our muscles form tendons that attach to our finger bones and this is how we bend our fingers. Our tendons are covered by a sheath ("tendon sheath"), which bathes the tendon in a very fine layer of fluid (think of it as motor oil), and this helps our tendons glide smoothly. Inflammation within that sheath can cause the tendon to becomes thickened. The thickened tendon cannot glide smoothly.
As we bend our fingers, the natural tendency of our tendon is to bowstring. Our body prevents this by using small straps (called "Pulleys") to hold the tendon against the finger bones. The problem is that an inflamed tendon becomes too thick to glide past these pulleys and it catches.
Many people wonder what causes the inflammation to develop within the tendon sheath. There are many causes for the inflammation, such as diabetes, or rheumatoid arthritis, or direct trauma to the finger, but most times a trigger finger occurs for reasons that doctors don’t understand.
There are different levels of severity.
A mild case is when there is tenderness at the base of the affected finger due to inflammation around this A1 pulley. A moderate case occurs when the finger feels like it is catching but is able to still move. A more severe case occurs when the finger can actually lock in a flexed position, but it can be straightened by using your other hand. Lastly, the most severe cases are when the finger gets locked and cannot be corrected.
How is a Trigger Finger diagnosed?
A trigger finger is suspected based on the symptoms a patient reports. Diagnosis of the condition is confirmed by the examination of the hand and affected finger. Doctors look for the symptoms of pain at the base of the finger, and catching and locking of the affected finger.
There are no x-rays or MRI scans required.
How is a Trigger Finger treated?
A Trigger Finger should be treated in a stepwise fashion, first with the least invasive treatments, moving to more invasive if the condition persists. Initial treatment is anti-inflammatory medication, like Motrin, as well as activity modification (dont hold things with a strong grip: heavy grocery bags are the worse, because your hand is completely flexed trying to hold the thin handle). Also taking time every morning to soak your fingers in warm water, and to slowly start moving them, like kneading dough, can loosen up the tendons and reduce the inflammation.
If this fails, then often a steroid shot can successfully decrease the inflammation and prevent future locking. Its effective in about 50% of cases. Sometimes a second injection is given, and this often causes the inflammation to go away completely.
Lastly, if steroid injections and therapy fails, then surgery can be performed to cut the A1 pulley which is catching on the tendon. This surgery, if done correctly, will definitively fix the problem because theres no long any tissue to cause the locking. There is little long term side effects of the procedure, other than post operative pain and patients typically do very well from the surgery.
The surgery can be done while you are awake (just the finger needs to be numbed-up with a local injection...like going to the dentist to get your tooth fixed). Here is a video from YouTube of an actual Trigger Finger Release surgery.
What is the long term outcome?
A single steroid injection cures trigger finger in about 45% of people (the issue hasn't returned by 5 years). Women benefit more than men (it cures their trigger finger 55% of the time vs. men only 35%). If you come in with multiple affected fingers, it drops the success of a single injection to about 35%. However, many people will benefit from a second shot, which pushes down the inflammation even more, and cures the problem.
Surgical treatment of trigger finger, when performed correctly, will cure the issue in 99.99% of cases (once the band is cut, its not coming back).
Note that for reasons not fully understood, some people are predisposed to getting trigger finger, and will see the condition develop in multiple fingers (after one finger is successfully treated).
Sometimes a trigger finger can flair up when there are other issues going on in the hand, like carpal tunnel syndrome. Doctors don't fully understand the link.
References
1) Wojahn RD et al. Long-term outcomes following a single corticosteroid injection for trigger finger. JBJS 2014; 96; 1849-1854. full article. single shot works 45%, better in women then men, worse in multiple fingers, diabetes has no effect.
2) Ryzewicz M, Wolf JM. Trigger digits: principles, management, and complications. J Hand Surg Am 2006; 31: 135-46. full article. review.
3) Patel MR, Bassini L. Trigger fingers and thumb: when to splint, inject, or operate. J Hand Surg Am 1992; 17: 110-3. full article. splinting works in 70%, injection in 90% of failed splint, surgery 100% of failed injection.
4) Newport ML et al. Treatment of trigger finger by steroid injection. J Hand Surg Am 1990; 15: 748-50. full article. 70% improved overall 50% after 1, 23% after 2, 5% after 3.
5) Rhoades CE et al. Stenosing tenosynovitis of the fingers and thumb. Results of a prospective trial of steroid injeciton and splinting. CORR 1984; 190: 236-8. full article. 70% improvement, only 40% if sx over 4 months.
6) Baumgarten KM. Corticosteroid injection in diabetic patients with trigger finger. A prospective, randomized, controlled double-blinded study. JBJS 2007; 89: 2604-11. full article. inject didnt help diabetics, 80% improve in normal peeps.
7) Rozental TD et al. Trigger finger: prognostic indicators of recurrence following corticosteroid injection. JBJS 2008; 90: 1665-72. full article. linear failure of injection to one year fu, only 50% good at 1 yr, young, diabetes, multi-finger risk for fail.