Trigger finger is an inflammation of tissue inside your finger or thumb. It is also called tenosynovitis(ten-oh-sin-oh-VY-tis). With this condition, the tendons become swollen. So does the synovium (a slick membrane that allows the tendons to move easily). This makes it difficult to straighten the finger or thumb. Trigger finger is often caused by repetitive gripping or squeezing hand motions which can irritate and inflame the tendons and the synovium. It can also be caused from arthritis or an injury to the palm of the hand. Sometimes the cause of trigger finger is unknown.
Tendons connect muscles in your forearm to the bones in your fingers. The tendons in each finger are surrounded by a protective tendon sheath. This sheath is lined with synovium, which produces a fluid that allows the tendons to slide easily when you bend and straighten the finger. If a tendon is irritated, it becomes inflamed. It can cause the lining of the tendon sheath to swell and thicken. Or the tendon itself may thicken. Then the sheath pinches the tendon, and the tendon can no longer slide easily inside the sheath. When you straighten your finger, the tendon sticks or “locks” as it tries to squeeze back through the sheath.
The first sign of trigger finger may be pain where the finger or thumb joins the palm. You may also notice some swelling. As the tendon becomes more inflamed, the finger may start to catch when you try to straighten it. When the locked tendon releases, the finger jumps, as if you were releasing the trigger of a gun. This further irritates the tendon, and may set up a cycle of catching and swelling.
Fortunately, trigger finger can be treated with both non-surgical and surgical methods. The treatment will depend on how severe the condition is.
If your symptoms are mild, your doctor may have you rest the finger or thumb and take oral anti-inflammatory medication, such as aspirin. If this does not reduce the swelling, your doctor may give you injections of an anti-inflammatory, such as cortisone, in the base of the finger or thumb, which reduces the inflammation and the tendon sheath is then open and able to allow the tendon to release and glide normally. Once the tendon can move freely again, the finger can bend and straighten.
If these treatments don’t relieve your symptoms, your doctor may recommend surgery. In this case the surgeon will open the sheath that surrounds the tendon to enlarge the space and release the swollen tendon. This allows the finger to bend and straighten normally again. Surgery takes only about 20 minutes, and can often be done under a local anesthetic. You are able to go home the same day. Your hand will be wrapped in a soft bandage, and you may wear a plaster splint for a short time to keep the finger stable and more comfortable. The stitches will be removed in about 2 weeks. Your doctor will discuss the risks and possible complications of surgery with you.