Pathology
Trigger finger is stenosing flexor tenosynovitis at the A1 pulley. The process is predominantly fibrocartilaginous thickening and tendon-pulley mismatch rather than acute inflammatory tenosynovitis.
Presentation
- pain at the volar MCP region
- catching or clicking
- locking in flexion
- fixed PIP contracture in advanced disease
It is associated with diabetes and is more common in middle-aged adults.
Examination
Palpate the A1 pulley while the patient actively flexes and extends the digit. Demonstrable catching supports the diagnosis.
Treatment
Non-operative
- activity modification
- splinting in selected patients
- corticosteroid injection around the flexor sheath/A1 pulley
Injection is less successful in some diabetic patients and in long-standing fixed contracture.
Operative release
Open A1 pulley release is reliable for persistent triggering. Percutaneous release is an option in selected digits but requires careful attention to neurovascular anatomy.
Initial management may include:
- activity modification
- splintage in selected cases
- corticosteroid injection
Persistent or recurrent triggering can be treated with percutaneous or open A1-pulley release.
Surgical pitfalls
- incomplete pulley release
- digital nerve injury
- scar tenderness
- stiffness
- bowstringing from excessive pulley release
Ask the awake patient to actively move the digit during local-anaesthetic surgery when the technique allows; this can confirm free tendon excursion.
Mechanism
Trigger finger is a stenosing flexor tenosynovitis at the A1 pulley region. Thickening of the tendon/pulley system impairs smooth tendon gliding and produces catching, locking or painful release.
Clinical features
- tenderness at A1 pulley
- palpable nodule
- triggering during flexion/extension
- fixed flexion in advanced cases
Differentiate from:
- Dupuytren contracture
- joint contracture
- tendon injury
- neurological spasticity
Associations
It is more common in patients with diabetes and can involve multiple digits. It may also occur with other systemic conditions.
Surgical safety
During release:
- protect digital neurovascular bundles
- ensure adequate A1 release
- avoid unnecessary injury to more distal pulley structures
- confirm free tendon excursion
FRCS synthesis
The essential concept is mechanical mismatch between flexor tendon and A1 pulley. Treatment restores gliding while preserving the pulley system needed for efficient flexion.