Trigger fingers are some of the more common things that I see as an orthopedic surgeon.

To first understand what a trigger finger or trigger thumb is, I want to first explain the anatomy of the hand. There are two flexor tendons for each finger including the index, middle, ring and pinky fingers. The thumb has one flexor tendon.

The flexor tendons allow you to bend your fingers in a position that allows you to grasp and grip objects. The flexor tendons are on the palmar (front part) of the hand. The tendons are not just “sitting there.” They wouldn't function very well if they didn't have some mechanical restraints on them.

Each tendon goes through a tendon sheath. The tendon sheath is lined with cells similar to the cells that line our joints (synovial cells) that produce fluid which lubricates the tendon as it goes through the sheath so that there is very limited friction. Having a sheath is not enough.

As you bend your fingers down, if there weren't some restraints on the tendon sheaths, the tendons would “bow string” and lack mechanical advantage. This would result in significantly decreased grip strength compared to what we have. Therefore, each finger has several pulleys over the tendon sheaths that help prevent bow stringing and improve the mechanical leverage of the tendons.

Unfortunately, with repetitive activity such as typing or activities that put pressure on the actual palm of the hand, directly on the tendons themselves, can cause inflammation and swelling within the tendon sheath. That can also lead to some swelling of the tendons themselves.

If a specific area of the tendon starts to get swollen, it will sometimes start to catch as it goes through the pulley. Patients will notice a catching type feeling but the finger won't necessarily lock. If the irritating activity or agent is not taken care of, this can get worse and the swelling within the tendon sheath can become an actual nodule or lump within the tendon itself. The nodule can slide trough the tendon sheath and through the pulley in one direction but unfortunately it gets caught as it comes back. If the nodule gets large enough, the finger can actually get stuck and will lock.

In order to get it straight or unlocked, it is often very painful and requires physical force. Hence the term “trigger finger.”

If this is caught early enough, a cortisone injection into the sheath will shrink the inflammation within the sheath (the tenosynovitis) and hopefully shrink the nodule/tendon itself to the point where it slides easier through the sheath and the trigger finger goes away. Sometimes it will take one injection, sometimes more.

Usually if two injections do not resolve the inflammation, then they probably are not going to work and the next step would be surgical intervention. There are some people for whom the shot will work for an extended period of time. They may need another one or periodic one down the road and they can avoid surgery.

However, if the shots don't work, there really isn't any other conservative treatment that is reliable. Surgical treatment becomes the next option. It usually is not a very difficult surgery but it is still surgery. It is usually done under local anesthetic but still has to be done under sterile conditions just like any other surgery.

A small incision is made in the palm of the hand. Dissection is carefully carried down to the tendon sheath itself and the A1 pulley is usually the offending pulley where the triggering occurs. A knife is utilized to cut the pulley along the tendon sheath which allows it to widen and now the nodule and the thick area can slide back and forth without any difficulty. It is extremely rare that this surgery is not effective. Usually, I have the patient, who is awake, demonstrate to me that the triggering is gone intraoperatively while I am actually looking at the sheath to make sure that I have released enough. You don't want to release too much because that can weaken the grip strength of that finger (remember the bow stringing).

Just like any surgery, there are some slight risks. They are typically very low and the surgery is very successful.

However, risks include, but are not limited to bleeding, infection, nerve or blood vessel damage, tendon injury, numbness and tingling, neuroma formation, recurrence, inability to relieve the symptoms, stiffness, continued pain, increase in pain, development of Reflex Sympathetic Dystrophy, wound problems, blood clots, bleeding problems, reactions to medications, medical problems and even death.

All of these are extremely rare and the surgery is usually successful.

Interestingly, many people who develop a trigger finger in one finger will often develop it in other fingers so perhaps there is some genetic pre disposition, i.e. their pulleys are tighter than someone who does not get trigger fingers and/or if they continue to perform repetitive irritating activities that can obviously lead to further trigger fingers.

Dr. Marc P. Pietropaoli is a board certified/fellowship trained orthopedic surgeon/sports medicine specialist and is president of Victory Sports Medicine & Orthopedics in Skaneateles