September 14, 2021
What is trigger finger/thumb?
If your finger gets stuck in a bent position or snaps when bent and straightened, then trigger finger can be the likely cause. The name trigger finger comes from the similarity with a gun trigger being pulled or released. This is a common cause of hand pain and is seen in roughly 2- 3 percent of general population. Thumb or ring finger of women in the fifth or sixth decade of life is most commonly affected. The condition can however involve multiple fingers and both hands.
What are the causes of trigger finger/thumb?
Tendons are rope like structures which attach the muscles to the bones. These are surrounded by a covering (sheath) and are held attached firmly to the bones by anchors called pulleys. A disparity in the size of the tendons and the sheath or the anchors results in the disruption of the smooth gliding mechanism and the resulting snapping or locking sensation is addressed as trigger finger.
The exact cause of this condition is not known, but its development may be related to activities requiring repeated gripping (like rock climbing) or physical activity involving extensive use of the hand as in repetitive screw driving. Certain professions such as farmers, industrial workers, musicians may experience this problem more often. Injuries to the pulley and tendon problems are seen in this condition.
This condition is seen more commonly in association with
- Diabetes – up to 10% of diabetics may be affected
- Rheumatoid arthritis
- Carpal Tunnel Syndrome or after surgery for this problem
- Renal disease or dialysis
- Mothers thumb or De Quervain’s disease
What are the symptoms of trigger finger/thumb?
The common symptoms include
- Stiffness and swelling especially in the morning
- Palpable painful nodule at the base of finger
- Clicking during movement of the finger
- Intermittent finger locking during bending often requiring extra effort to straighten the finger
- In severe cases the affected finger may become locked in a bent position
How is trigger finger/thumb diagnosed?
The diagnosis of trigger finger is based on the medical history and clinical examination. The key finding is locking of the finger when it is bend, with snapping when it is straightened. Ultrasound is an inexpensive and easily available modality used to assess the severity and measure the thickness of the affected sheath. A guided injection for relief can be performed at the same time for relief. Ultrasound offers the advantage of being able to compare to the other side and perform a dynamic assessment (assess the problem as the finger is being moved).
What are the treatment options for trigger finger/thumb?
Most cases are treated conservatively with rest, activity modification, splinting, anti-inflammatory medications, physical therapy and local injections. Early treatment of trigger thumb has been associated with better outcomes. Splints can limit motion and reduce aggravating activities. These are usually worn for 6-10 weeks although are less effective in individuals with severe triggering or longstanding symptoms.
A small amount of steroid with local anaesthetic is used for injection under ultrasound guidance. Unguided injections without ultrasound may risk injury to surrounding structures such as nerves and blood vessels. Dr Manocha routinely preforms these injections under ultrasound guidance in his OPD as guided injections are more accurate. Injections are a low-cost alternatives to surgery with less complications and quick return to work.
The injection can reduce inflammation and resolve pain, triggering in up to 75% of cases. Some individuals may require more than one injection. If a series of two injections do not resolve the problem, then the surgical option can be considered. Surgery is successful in vast majority who fail to improve with the above measures. Options include open, endoscopic or percutaneous release.