Trigger finger occurs due to narrowing of the A1 pulley of flexor tendon sheath causing entrapment of the flexor tendon with restriction of flexion and extension movement
Most common in long and ring finger is most common in adults
Women older than 50 years of age
Generally associated with diabetics and inflammatory arthropathy
Etiology
Repetitive grasping activities
Types
- Primary
- Secondary
- DM
- Gout
- RA
- Amyloidosis
- Storage Disorder
Involvement of dominant hand
Histologically
Fibrocartilagenous metaplasia of flexor tendon sheath
- Nodular: localized swelling is a free mobile
- Not well-defined and widespread
Classification of trigger finger
Green Classification
| Grade | Description |
|---|---|
| I | Pain and tenderness of A1 pulley |
| II | Catching of digits |
| III | Locking of digits; passively correctable |
| IV | Fixed, Locked digit |
Quinnell’s Classification
| Grade | Description | Prognosis |
|---|---|---|
| I | Normal movement, no pain | Excellent |
| II | Normal movement, occasional pain | Good |
| III | Uneven movement | Poor |
| IV | Intermittent locking, actively correctable | Poor |
| V | Locking, only passively correctable | Poor |
Management Options
Splinting
Immobilized the joint and reduced the movement of the tendon within flexor sheath
Corticosteroids
Success rate: 60-92%
Most effective in primary trigger finger, single finger, nondiabetic
Can be used with/without Local anesthesia
- Betamethasone
- Dexamethasone
- Triamcinolone
Rare complications
- Tendon rupture
- Fat necrosis
- Skin necrosis
- Injury to the digital nerve
Per-cutaneous release
Indicated in recurrence following repeated corticosteroid injection
A similar outcome to open surgery
After hyperextension of the MCP joint, the hypodermic needle is passed through the flexor tendon sheath incised proximally and distally
Open release
- Failed conservative treatment
- Digit cannot be fully extended at IP joint
- A1 pulley is cut under direct visualization taking care not to damage A2 pulley
- Followed by non-restricting bandages
In Rheumatoid arthritis:
The entire annular pulley system should be preserved to prevent further ulnar drift to the finger
They are treated with tenosynovectomy and excision of one slip of FDS
Trigger thumb
Trigger thumb is different from congenital trigger thump
Similar to trigger finger
Newer evidence has found a fourth pulley in 75% of cases, which may contribute to stenosis
Congenital trigger finger
Incidence: 3/1000
Etiology: Unknown
Often bilateral:
- Congenital
- Storage disorder
- DM
Unlike in adults, the thumb does not trigger but remains in FFD of the IP joint (Development rather than congenital)
Pathological Nodular tendon thickening: Notta Node
Treatment Options
Observation initially
Generally doesn’t respond to conservative treatment
In some cases, spontaneous resolution occurs
Hence, the period of observation of 3 years ( Upper limit) before attempting surgical correction i.e. Annular pulley release to prevent IP joint contracture
In Pedriatic trigger finger
Generally caused by anatomical anomalies
Treatment depends upon cases
A1 Pulley release may not resolve to trigger, additional A3 release or resection of ulnar FDS slip may be required
