A Patient's Guide to Trigger Finger and Trigger Thumb
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Introduction
Trigger finger and trigger thumb are conditions affecting
the movement of the tendons as they bend the fingers or thumb
toward the palm of the hand. This movement is called flexion.
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This guide will help you understand
how trigger finger and trigger thumb develop
how doctors diagnose the condition
what can be done for the problem
Anatomy
Where does the condition develop?
The tendons that move the fingers are held in place on the bones
by a series of ligaments called pulleys. These ligaments form an
arch on the surface of the bone that creates a sort of tunnel for
the tendon to run in along the bone. To keep the tendons moving
smoothly under the ligaments, the tendons are wrapped in a slippery
coating called tenosynovium. The tenosynovium reduces the
friction and allows the flexor tendons to glide through the tunnel
formed by the pulleys as the hand is used to grasp objects.
View of extended finger with pulley,
tendon,and tenosynovium.
View of flexed finger with pulley,
tendon, and tenosynovium.
Causes
Why do I have this problem?
Triggering is usually the result of a thickening in the tendon
that forms a nodule, or knob. The pulley ligament may thicken as
well. The constant irritation from the tendon repeatedly sliding
through the pulley causes the tendon to swell in this area and create
the nodule. Rheumatoid arthritis, partial tendon lacerations, repeated
trauma from pistol-gripped power tools, or long hours grasping a
steering wheel can cause triggering. Infection or damage to the
synovium causes a rounded swelling (the nodule) to form in the tendon.
View of a nodule.
Triggering can also be caused by a congenital defect that forms
a nodule in the tendon. The condition is not usually noticeable
until infants begin to use their hands.
Symptoms
What does a trigger finger or thumb feel like?
The symptoms of trigger finger or thumb include pain and a funny
clicking sensation when the finger or thumb is bent. Pain usually
occurs when the finger or thumb is bent and straightened. Tenderness
usually occurs over the area of the nodule--at the bottom of the
finger or thumb. The clicking sensation occurs when the nodule moves
through the tunnel formed by the pulley ligaments. With the finger
straight, the nodule is at the far edge of the surrounding ligament.
When the finger is flexed, the nodule passes under the ligament
and causes the clicking sensation. If the nodule becomes too large
it may pass under the ligament, but becomes stuck at the near edge.
The nodule cannot move back through the tunnel, and the finger is
locked in the flexed trigger position.
View of nodule in tendon with extended
finger.
View of nodule in tendon with flexed
finger.
Diagnosis
How do doctors identify the condition?
The diagnosis of trigger finger and thumb is usually quite obvious
on physical examination. Usually a palpable click can be felt as
the nodule snaps under the first finger pulley. If the condition
is allowed to progress, the nodule may swell to the point where
it gets caught and the finger is locked in a bent, or flexed position.
No special tests or X-rays are required.
Treatment Options
What can be done for the condition?
Unfortunately, very little can be done, short of surgery, once
a finger or the thumb has developed triggering. A cortisone injection
into the tendon sheath may decrease the inflammation and shrink
the nodule to relieve the triggering, but the results will probably
be short lived. If your problem just started and the tendon isn't
triggering, a splint may be used after the injection. The splint
is used to rest the tendon and attempt to get the inflammation and
nodule to shrink.
View of cortisone injection into
the sheath.
Surgery
The usual solution for treating a trigger digit is surgery to open
the pulley that is obstructing the nodule and keeping the tendon
from sliding smoothly. This surgery can usually be done as an outpatient
procedure, meaning you can leave the hospital the same day.
The surgery can be done using a general anesthetic (one that puts
you to sleep) or a regional anesthetic. A regional anesthetic blocks
the nerves going to only a portion of the body. Injection of medications
similar to novocaine are used to block the nerves for several hours.
This type of anesthesia could be an axillary block (only the arm
is asleep) or a wrist block (only the hand is asleep). The surgery
can also be performed by simply injecting novocaine around the area
of the incision.
Once you have anesthesia, your surgeon will make sure the skin
of your palm is free of infection by cleaning the skin with a germ
killing solution. An incision will be made in the skin. There are
several types of incisions that can be made, but most are made along
the natural creases and lines in the hand. This will help make the
scar less noticeable once the hand is healed.
The skin and fascia are separated so the doctor can see the tendon
pulley. Special care is taken not to damage the nearby nerves and
blood vessels.
Then your surgeon will carefully divide the tendon pulley. Once
the tendon pulley has been separated, the skin is sewn together
with fine stitches.
View animation of surgery.
Rehabilitation
What should I expect following treatment?
The effect of nonsurgical treatment is usually short-lived. You
may get some relief of symptoms with a cortisone injection. If you
wear a splint to get the area calmed down, the nodule may shrink
temporarily, but patients often end up needing surgery for this
problem.
If you do have surgery, afterward you'll wear a bandage over the
area until the stitches are removed. You will probably have a fairly
large padded bandage on your hand when you return form surgery.
This is to provide gentle compression and reduce the bleeding and
swelling that occurs immediately after surgery. This can be removed
fairly quickly, and usually only a Band-Aid&TM& is required
after the first twenty-four to forty-eight hours. You'll begin gentle
range-of-motion exercises a few days after surgery.
Most patients won't need to participate in a formal rehabilitation
program unless the finger or thumb was locked for a while before
surgery. In these cases, the finger or thumb may not straighten
out right away after the surgery. A physical therapist may apply
a special brace to get the finger or thumb to straighten. The therapist
may also apply heat treatments, soft-tissue massage, and hands-on
stretching to help with the range of motion.
Some of the exercises you'll begin to do are to help strengthen
and stabilize the muscles and joints in the hand. Other exercises
are used to improve fine motor control and dexterity. You'll be
given tips on ways to do your activities while avoiding extra strain
on the healing tendon. You may need to return to therapy two to
three sessions each week for up to six weeks.
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