Trigger Finger

Part II

What causes trigger finger?

We do not know exactly what causes trigger finger, but we do know some things. The tendon is subjected to significant forces at the A1 pulley, which is where trigger finger occurs. Trigger fingers show changes in the substance of both the tendon and the pulley called "fibrocartilaginous metaplasia", which means that some of the cells change into cells that have the characteristics of cartilage cells such as those found in intervertebral disks. The cells show an increase in both the size of the cells and the number of cells. The smooth gliding layer of the tendon and the pulley change, with fraying and disintegration of the surface. We do not see these high forces or cellular changes in other areas of the flexor tendons, therefore we feel that these changes must be related to the disease called trigger finger. (Trigger Digits: Diagnosis and Treatment, by Miguel J. Saldana, MD; Journal of the AAOS, July/August, 2001, pages 246-252)

What are the symptoms of trigger finger?

The hallmarks of trigger finger is painful popping of the digit and pain in the palm at the A1 pulley level. The popping is usually worse in the morning when you first get up, but as the problem progresses, it can pop all the time. When it is really bad, the bump in the tendon cannot pass under the pulley and the finger is "locked", that is, it cannot straighten (or bend, if it is stuck out straight).

Who gets trigger finger?

Many people think trigger finger should come from a long history of hard work, but hard labor does not seem to be very related. It can come from an episode of overuse, but is usually not associated with any period of heavy use. It usually comes on gradually, and typically comes in our 40's, 50's, and 60's. It is about two to three times more common in women than in men, and the fourth finger is the most often involved. It is common for patients to get it in more than one finger. If they do, it is often either the same finger in both hands, or two adjacent fingers. I have only had one patient who had it in all 10 fingers, and he was a 60 year old who played handball. I think if you are 60 and go around whacking things with your palm, you should expect to get problems! Most patients will get it in only one or two fingers.

How is trigger finger diagnosed?

The diagnosis is made by listening to the patient and by examining the patient. Most patients will have a history of painful clicking and popping, without any history of trauma. There will be a painful nodule in the palm, exactly at the A1 pulley location.

How is trigger finger treated?

Making the diagnosis is usually quite simple. The next step is very important: patient education.  The third step in my general treatment regimen for all hand problems is activity modification. This step does not really apply much to trigger finger. It is usually not due to overuse.  The fourth step in my general treatment regimen for all hand problems is anti-inflammatory medication. This usually does not help in the treatment of trigger fingers. It is not strictly an inflammatory condition, since the changes are not just the changes of inflammation, but of fibrocartilangenous metaplasis (see section above for explanation).

The fifth step is splints. While they will work as long as you wear the splints, you will not be able to do anything with your hand. If the trigger digit was minimally symptomatic and you happened to do something that made you hand swell, a temporary splint may help. What is easy and can help is to tape the finger at night.  By placing a one inch piece of tape lightly around the joint helps to comfortably splint the finger in extension and avoids a common problem of a painfully locked finger in the morning.  Once up, remove the tape and start some normal use; some stiffness in the morning is common.  The sixth step in my general treatment regimen for all hand problems is hand therapy. While I use a lot of hand therapy in my practice, there is only a little that hand therapy can offer this condition.

The seventh step in my general treatment regimen for all hand problems is steroid injection, and this is a great way to treat trigger fingers. I presented a study at the American Society for Surgery of the Hand showing that one injection was curative (through 2 years of follow up) in 75% of cases, and a two injections in 90%, pretty good odds.  It is not a good idea, in general, to give more than 2 injections in any one location in the body, as it can cause some collagen degeneration. You can have 2 in each involved finger.

The final step is surgery.  About 10% of trigger fingers go on to surgery. The longer you waited to come see me, the greater the chance that you will need surgery. It is out-patient surgery (that is, you don't stay overnight in the hospital). You don't even have to eat the hospital food!

Continued on Page 3

Revised 10/7/09 wh