Trigger Finger / Thumb
Painful Finger and Thumb
Trigger finger/thumb is a condition affecting the gliding movement of the tendon as you bend or straighten the finger/thumb.
To understand the pathology behind trigger finger/thumb, let us look at how the tendon function normally in the finger/thumb. These tendons extend from the forearm to the end of the digit. When they pull, the fingers and thumb will bend. Within the finger/thumb, they are held close to the bones by fibrous tissue called pulleys which form a tunnel for the tendon passage. The tendons are covered by a slippery coating called tenosynovium that reduces the friction during tendon gliding as the finger bends and extends. The pulley at the entrance of the tunnel located at the base of the finger is called the A1 pulley.
What causes trigger finger?
It is the result of thickening of the tenosynovium or narrowing of the pulley. Constant irritation from the tendon sliding repeatedly through the pulley causes the tendon to swell and creates a nodule near the A1 pulley.
Who gets trigger finger?
Anyone can get trigger finger. But it is commonly seen in women between the ages of 40-60.
Certain conditions such as rheumatoid arthritis and diabetes mellitus predispose the patients to trigger finger. Partial tendon laceration, repeated trauma or occupation requiring long hours of grasping can lead to trigger finger too.
Triggering is also observed in infants and young children. It commonly affects the thumb but other fingers can be affected too.
How do i know if I have trigger finger?
You will have ‘clicking’ and/or pain at the palm side of the base of finger/thumb as the finger/thumb is straightened or bent. These symptoms can be more pronounced in the morning. In later stage, there is more difficulty in straightening or bending the finger/thumb. Sometimes, a bent finger can only straighten with a gentle force, usually followed by a click and pain. In severe cases, the finger is locked in a bent position and cannot be straightened even with force.
The doctor will examine your hand to exclude other conditions that may present similar to trigger finger such as infection, arthritis, extensor tendon subluxation.
Treatment depends on the severity of triggering and how much it affects your daily function.
In mild early cases, you can treat them with finger exercise and stretching. You may need to change your activities to prevent triggering and give the inflamed tendon time to heal.
Steroid injection adjacent to the A1 pulley area can decrease the inflammation and swelling. It helps to relieve the triggering. It is very effective but may be short lived. There is a small risk of injuring the finger tendon, nerve and blood vessel.
Surgery is required if the triggering is troublesome and interferes with your work and activity or when the finger is difficult to straighten or locked. The A1 pulley which forms the entrance of the tunnel is released. If the tenosynovium is thickened, this may be excised too. This surgery is commonly performed under local anaesthesia in a Daycare surgery setting. This surgery is safe and very successful. There will be mild scar tenderness for few weeks. Nerve and blood vessels injury is uncommon.
A1 pulley divided to release the entrapped tendon
Dr Low Tze Hau
Consultant Hand and Microreconstructive Surgeon Orthopaedic Surgery
Hand and Microsurgery
Dr Ng Eng Seng
Consultant Hand and Microsurgeon
Hand and Microsurgery