A cause of painless or painful catching of the finger or thumb flexor tendon after you bend the digit with a “pop” or locking as you straighten it. On occasion, the finger will lock in a bent position and need to be manually straightened into full extension. This can eventually lead to contracture of the finger joints.
CAUSE
Each tendon passes through a tight tunnel to help the motion of the finger and keep the tendon close to the joint(s) it moves. Triggering is due to increased pressure especially with repeated power grip at the edge of the tunnel that causes thickening of the edge of the tunnel and/or swelling of the tendon.
DEMOGRAPHICS
Trigger finger is most common in middle-aged women. It can involve several fingers. In patients with multiple trigger digits, the most commonly affected digit is the thumb, followed by the ring, long, little, and index. It is associated with diabetes, gout, renal disease, rheumatoid arthritis and other rheumatic diseases and is associated with a worse prognosis in these conditions. It can seem like the locking is occurring at the joint.
PRESENTATION
A history of catching or locking of the digit on bending, occasionally with pain in the palm. Often worse in the morning and maybe locked bent first thing in the morning but improve throughout the day. More significant cases have demonstrable catching with contracture of the finger joint.
Most primary trigger digits in adults can be successfully treated non-surgically with the use of a steroid injection. This has a low complication rate and is successful in up to 75% of cases, depending on chronicity – i.e. the longer you have had the trigger the less likely a steroid injection will fix it. Diabetics may experience a transient rise in blood glucose levels. Splinting can be considered and is effective 50-60% of the time.
OPERATIVE TREATMENT
Trigger finger is not a dangerous condition. Your decision on whether to have surgery is based on the symptoms and how problematic they are for you. If your finger is stuck bent surgery may help prevent permanent stiffness.
The aim is to “release” the opening of the tunnel so that the tendon can slide without catching. This is usually done as a day case and often under local anaesthetic.
The surgery is performed through a small incision in the palm and the tunnel is cut (released) so there is more room for the tendon to move through it.
Reproduced and adapted from Griffin LY (ed): Essentials of Musculoskeletal Care. 3rd Ed. Rosemont, IL. American Academy of Orthopaedic Surgeons, 2005.