Trigger Finger is a condition of the hand that results in locking your fingers or the thumb in a bent position, but also present earlier with clicking, swelling or pain in the digit. Physically, trigger finger or thumb may be quite debilitating. Trigger finger may affect one or more digits at a time.
It is also possible to suffer from other stenosing conditions of the hand simultaneously, including carpal tunnel syndrome and De Quervain’s tenovaginitis.
When left untreated, carpal tunnel syndrome and trigger finger may result in weakness of the hand, and potentially stiffness of the joints.
If you suffer from this painful condition, it is highly recommended to visit an orthopaedic hand surgeon to improve your quality of life.
Understanding the anatomy of fingers
To understand why the trigger finger occurs, you will have to first understand the anatomy of your fingers and hand.
You have bones in your fingers which provide stability, which are connected via joints which allow movement.
These actions are only possible due to the pull of flexor and extensor tendons, which are attached to muscles. These are cord-like structures joining all finger bones and the forearm muscles. When the forearm muscle contracts, the flexor tendon pulls on the bone, resulting in the bending of the finger.
Now, each flexor tendon runs underneath a tight tunnel that helps in the smooth gliding of tendons while bending and straightening the fingers. This tunnel, termed as tendon sheath, has an A1 pulley at its opening, located in the palm of the hand. An A1 pulley is a strong band of tissue that is the entrance of the tunnel.
Just like how a pulley works in a mechanical system, the A1 pulley works the same during the bending and straightening of fingers.
The cause of trigger finger
When the A1 pulley or the band of tissue near the tunnel opening gets inflamed, it restricts the smooth gliding of flexor tendons when fingers are bent.
Over time, the inflammation gets more pronounced, and a small nodule develops on the flexor tendon. When the nodule passes through the pulley, the sensation of clicking, locking or catching is observed. The sensation may bring with it immense pain with your finger being stuck in a bent position.
The A1 pulley may become thickened due to overuse, inflammatory causes (eg. rheumatoid arthritis), or secondary to other medical causes such as diabetes mellitus.
Common symptoms of trigger finger
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Stiffness of finger(s) in the morning
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Nodule formation or soreness at the base of your thumb or finger
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Popping/clicking sound while moving fingers
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A painful clicking while bending or straightening finger
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Locking of finger or thumb in a bent position which is impossible to straighten without the use of the other hand.
Often the symptoms are more pronounced during the morning time or when you are grasping something firmly.
Risk factors of trigger finger
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Age: This painful condition mostly occurs in people falling between the age limit of 40 to 60.
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Gender: Trigger finger more often occurs in women than men.
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Health conditions: People with health conditions like diabetes, rheumatoid arthritis, and gout are most likely to experience this painful condition.
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Trauma/Surgery: Patients recovering from an injury or post-surgery may develop swelling and trigger finger
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Workspace hazards: Often, this condition comes as a by-product of certain occupations.
Getting the right diagnosis
Trigger finger or trigger thumb cannot be diagnosed through lab tests or x-rays. An experienced orthopaedic hand surgeon will take a history and perform a series of physical examinations to get the correct diagnosis.
Once the orthopaedic hand surgeon diagnoses you with a trigger finger, your treatment starts depending upon the severity of symptoms. Often, a local anaesthetic and cortisone injection is recommended into the affected tendon sheath to reduce the inflammation and the symptoms. Other treatments include rest, physiotherapy and the use of splints to keep the finger straight, and surgery when the other options fail or are not appropriate.
