What is trigger finger?
The muscles of the forearm allow us to form a fist and to flex and straighten our fingers. These muscles connect to the finger with tendons. These tendons pass through a tunnel called the tendon sheath on the way to the fingers. On the tendon sheath are pulleys that keep the tendons close to the bone to provide smooth gliding motions. The pulley at the base of the finger is called the A1 Pulley and is involved with trigger finger. When the pulleys thicken and stiffen the tendon can get stuck.
Also called stenosing tenosynovitis or flexor tendinitis, trigger finger is a swelling of the tendon pulleys that flex/bend the fingers. It is a painful condition that in the worst case causes the finger to lock in the bent position. The thumb and ring finger are most commonly affected.
The lifetime risk of trigger finger is 2.6%. But the lifetime risk of trigger finger for people with diabetes is 10%. The average age of onset is 58. Women are 2-6 times more at risk than men. The thumb and ring finger on the right hand are most commonly affected.
What are the symptoms?
- Pain and discomfort at the base of the affected finger or thumb
- Reduced finger movement
- Painful stiffness that worsens with inactivity and is worse in the mornings
- A catching and popping sensation with finger movement
- Finger locking
- Nodules at the base of the affected fingers that become tender
What causes trigger finger?
Repetitive strain (overuse) that involves the fingers and thumb causes inflammation and swelling of the flexor tendon A1 pulley causing tendinitis. Abnormal thickening, scarring and inflammation of the A1 pulley and the flexor tendon causes catching and locking, pain, stiffness and restricted motion. Additionally, the A1 canal narrows. A tender lump at the base of the finger on the palm is a symptom of the inflammation of the flexor tendon A 1 pulley.
Who is at risk for trigger finger?
- Anyone who is involved with forceful hand activities like repeated strong gripping including farmers, musicians and many industrial workers
- People with carpal tunnel syndrome. Carpal tunnel surgical release is associated with development of trigger finger.
- People with diabetes.
- A high HbA1c is an independent risk factor for development of trigger finger.
- People with thyroid dysfunction
- People with rheumatoid arthritis
Your OANC hand doctor will ask about your symptoms and conduct a physical examination to check for nodules, stiffness, tenderness, swelling and range of motion.
When caught early, first line treatment for acute tendinitis includes a night splint, icing and oral anti-inflammatory medications to help decrease swelling and improve grip strength, pain and frequency of triggering events. Activity modification will be recommended. When symptoms persist, the focus is on decreasing swelling and pain. A steroid injection into the tendon sheath can relieve symptoms. If symptoms do not resolve within six weeks, a second injection will be recommended. Studies report that steroid injections can effectively treat trigger finger symptoms in about 57% of cases with one injection and 86% of cases after a second injection. After two failed steroid treatments, surgery will be recommended.
The goal of surgery is to release the tendon constriction so that the tendons can more easily glide to open and close the fist and bend and straighten the fingers. When the finger or thumb is locked in position surgery at the base of the affected finger will be recommended.
Open surgery to release the tendon is the gold standard and has a success rate of 99%.
However, a less invasive procedure with less risk is outpatient trigger finger surgery called percutaneous release that is performed under local anesthetic. A small incision is made at the base of the affected finger, or the tip of a sterile needle is inserted to release the tendon. The success rate is between 74% and 94%. If percutaneous release is insufficient open surgery will be recommended.
Orthopedic Associates of Northern California in Chico, California our board-certified orthopedic surgeons are here to help. Contact us to learn more about your condition and treatment options.