Does trigger finger only affect finger extension?

Trigger Finger Affects Both Flexion and Extension, Not Just Extension

Trigger finger affects both flexion and extension movements, not just extension. The condition involves abnormal resistance during both flexion and extension of the affected finger, with characteristic catching or locking that can occur in either direction 1.

Pathophysiology and Mechanism

Trigger finger (stenosing flexor tenosynovitis) is characterized by:

• Inflammation and subsequent narrowing of the A1 pulley in the finger 2
• Development of a nodule or thickening in the flexor tendon that catches on the pulley
• Abnormal resistance to smooth movement in both directions:
  • During flexion: The nodule may have difficulty passing through the narrowed pulley
  • During extension: The nodule catches on the pulley, causing the characteristic "triggering" or locking 1

The condition represents a tendinopathy rather than a purely inflammatory process, similar to other tendinopathies like medial epicondylitis 3.

Clinical Presentation

The classic presentation includes:

• Pain at the base of the affected finger
• Clicking or popping sensation during finger movement
• Catching or locking of the finger during both flexion and extension movements
• In severe cases, the finger may become locked in flexion, requiring passive manipulation to extend 2
• Morning stiffness and discomfort that may improve with activity

Diagnostic Considerations

Diagnosis is typically based on clinical presentation, with patients reporting:

• Clicking or locking of the finger during movement 2
• Difficulty with both flexion and extension
• Pain localized to the A1 pulley region

Advanced imaging like ultrasound can visualize tendinous structures but is generally only needed when the diagnosis remains uncertain 3.

Treatment Options

Treatment should follow a stepwise approach:

1. Conservative management:

   • Activity modification to reduce repetitive finger movements
   • Splinting to prevent full flexion and rest the tendon
   • NSAIDs for pain relief 3

2. Corticosteroid injections:

   • Effective first-line therapy for most patients 1
   • Less effective in people with insulin-dependent diabetes
   • Caution: Patients should be warned about returning to sports prematurely after injection to prevent tendon rupture 4

3. Surgical options (for persistent symptoms):

   • Percutaneous A1 pulley release
   • Open A1 pulley release
   • Excision of a slip of the flexor digitorum superficialis for persistent triggering despite A1 release 5

Important Considerations

• Trigger finger affects approximately 2% of the general population and up to 20% of adults with diabetes 1
• The condition is more common in women and typically occurs in the fifth to sixth decade of life 2
• Recent advances in treatment include extracorporeal shock wave therapy (ESWT) and ultrasound-guided procedures 6
• Patients should be encouraged to gradually resume activities after corticosteroid injection to prevent tendon rupture 4

Understanding that trigger finger affects both flexion and extension movements is crucial for proper diagnosis and management of this common hand condition.