The Tendons (Blue) go through a Tight Sheath (Purple)
The Tendon Gets Stuck in its Sheath, Causing Trigger Finger
Trigger Finger Release
Trigger finger and trigger thumb are extremely common. Triggering is due to a space problem, very similar to carpal tunnel syndrome except that, instead of a nerve getting pinched, it's the tendon that bends the finger or thumb that gets compressed. All of the flexor tendons that bend our fingers and thumb pass through tight tunnels in our fingers. This is where the compression occurs. As we age, or due to diabetes, thyroid disorders, or sometimes for unknown reasons, the tunnel stiffens and shrinks. Or the lining of the tendon (the tenosynovium) gets larger, due to swelling or thickening. The tendon that runs through it gets stuck and often "balls up" to form a palpable nodule in front of the pulley.
People with trigger finger often wake up in the morning with the involved digit(s) stuck down against the palm of their hand. Pulling it straight causes a significant amount of pain. Once the finger warms up it may move better, but there is a painful locking/clicking. Forceful gripping may also be painful. Splinting may prevent the finger from bending and catching, but usually doesn't provide significant long-term cure.
Less commonly, the finger can get stuck straight. In these cases, bending the finger is difficult and there is pain and tenderness at the palm of the hand near the base of the finger. In very early cases, the fingers simply feel "slow" or "sluggish" in the morning.
To make an analogy: If you were driving a truck that got stuck under a bridge, the first step to solving the problem would be to let some air out of the tire to decrease the height. For triggering, a steroid injection is helpful because it can create more space by decreasing inflammation and thinning the tendon lining. This gives the tendon more room to get through the tunnel. If you catch triggering early, a steroid injection can be curative. After 4-6 months, the chance of an injection permanently curing the condition is lower, but still worth a try.
If the trigger finger returns following an injection, subsequent injections often have "diminishing returns", meaning they won't work as well or last as long. If two injections fail, further injections will not work.
Fortunately, there is a quick, minimally-invasive outpatient surgery that is extremely effective. The Trigger Finger Release (or Trigger Thumb Release) is done through a small incision. The tight area of the tunnel that is compressing the tendon is released and the wound closed. To use our previous example, this is analogous to "raising the bridge" to allow the truck to get through. This is a very successful operation, and is almost always a permanent cure.
After surgery, keep the hand clean and dry for 3 days. Bathing is safer than showering. Wrap a towel around the hand in case any water gets in, then place a plastic bag over the hand and secure it tightly with rubber bands. After 3 days showering is allowed. Avoid submerging the hand under water for 10 days. There's a piece of special tape over the wound. The longer it stays, the nicer the wound will look. It'll fall off when it's ready. There are no stitches to remove. I recommend avoiding heavy activities like lifting and gripping for 2 weeks after surgery, in order to minimize post-operative pain. If you overdo it, a steroid injection is usually very helpful in decreasing inflammation.