TRIGGER FINGER/ THUMB
- A Trigger Finger is described as the catching or locking of a finger in a bent (flexed) position.
- Stenosing tenosynovitis, more commonly known as “trigger finger” or “trigger thumb”.
- Affecting the tendons that bend the fingers.
- Caused by inflammation that prevents the tendon from gliding smoothly.
- Tendons that bend the fingers pass through a series of loops, called “pulleys”.
- If the tendon swells, or if the pulleys tighten, the tendon can get caught which limits smooth motion of the finger.
The pulleys are of two types:
- Annular A – These are composed of single fibrous bands. Thus these are ring-like structures
- Cruciate C – Cruciate pulleys consist of crossing fibrous bands.
- A1 – over metacarpophalangeal joints. It is the pulley where triggering phenomenon occurs.
- A2 – over proximal end of the proximal phalanx
- C1 – over the middle of the proximal phalanx
- A3 – over the proximal interphalangeal (PIP) joint
- C2 – over the proximal end of the middle phalanx
- A4 – over the middle of the middle phalanx
- C3 – over the distal end of the middle phalanx
- A5 – over the proximal end of the distal phalanx
- more common in diabetics
- More common in women
- ring finger most commonly involved
- diabetes mellitus
- rheumatoid arthritis
- finger clicking
- pain at distal palm near A1 pulley
- finger becoming “locked in flexed position
- Physical exam
- tenderness to palpation over A1 pulley
- a palpable bump may be present near the same location
night splinting, activity modification, NSAIDS
- first line of treatment
- best initial treatment for fingers, not for thumb
- give 1 to 3 injections in flexor tendon sheath
- diabetics do not respond as well as non-diabetics
surgical debridement and release of the A-1 pulley
- in cases that fail nonoperative treatment
release of A1 pulley and 1 slip of FDS (usually ulnar slip)
- pediatric trigger finger
- presents with Notta’s nodule (proximal to A1 pulley), flexion contracture and triggering
- may need to release remaining FDS slip and A3 pulley as well
- Stenosing tenosynovitis of the flexor tendon sheath is also known as Trigger finger.
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