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📋 Condition Guide2024-01-16

Trigger Finger: Causes, Symptoms, and Treatment

Trigger finger (stenosing tenosynovitis) is a condition where a finger gets stuck in a bent position due to inflammation of the tendon sheath. It can be painful and can progress to a permanently locked finger.

Educational content only. This article is not medical advice. Always consult a qualified orthopedic surgeon or physician for diagnosis and treatment.

What Is Trigger Finger?

Trigger finger — medically known as stenosing tenosynovitis — is a painful condition where inflammation of the flexor tendon sheath causes a finger to catch, click, or lock in a bent position. When released, it often snaps back suddenly, like pulling a trigger.

Any finger can be affected, including the thumb (trigger thumb). The ring finger and thumb are most commonly involved.

Anatomy

The flexor tendons of each finger run through tight fibrous sheaths (like tunnels) called tendon sheaths or pulleys. The A1 pulley is the entrance pulley at the base of each finger. In trigger finger:

  1. Inflammation of the tendon or its sheath causes swelling of the tendon
  2. The swollen tendon struggles to glide smoothly through the A1 pulley
  3. A nodule (thickening) forms on the tendon
  4. As the finger bends, the nodule catches at the pulley and locks the finger in flexion
  5. Forcing the finger straight causes a painful "trigger" as the nodule pops through the pulley

Causes and Risk Factors

  • Repetitive gripping: Prolonged or forceful gripping (power tools, scissors, farming)
  • Diabetes: Significantly increases risk; can cause multiple trigger fingers
  • Rheumatoid arthritis
  • Female sex (women 6x more commonly affected)
  • Age: Most common 40–60
  • Hypothyroidism, gout, amyloidosis
  • Carpal tunnel syndrome frequently coexists

Symptoms

Graded by severity:

  • Grade I: Pain, tenderness at A1 pulley; no triggering
  • Grade II: Active triggering — finger locks and unlocks with active finger motion
  • Grade III: Passive triggering — requires help from the other hand to straighten
  • Grade IV: Fixed flexion deformity — finger locked in bent position, cannot be passively straightened

Additional symptoms:

  • Morning stiffness that loosens with movement throughout the day
  • Palpable nodule at the base of the affected finger
  • Pain at the base of the finger or palm

Diagnosis

Trigger finger is diagnosed clinically based on history and examination findings:

  • Tenderness directly over the A1 pulley
  • Palpable nodule on the tendon
  • Demonstrable triggering or locking
  • Assessment of triggering grade

X-ray is not routinely needed; ultrasound can confirm the diagnosis and guide injection.

Treatment

Corticosteroid Injection (First-Line)

A corticosteroid injection into the tendon sheath at the A1 pulley is highly effective:

  • Single injection success rate: 50–70%
  • Two injections, if needed: up to 80–85% success
  • Works best in early stages (Grade I–II)
  • Diabetes patients have lower response rates
  • Effects typically last 4–6 months; may be repeated

Splinting

Night splinting of the MCP joint in slight extension reduces triggering and allows tendon rest; used as an adjunct or alternative to injection.

Physical/Occupational Therapy

Tendon gliding exercises, activity modification, ergonomic assessment.

Surgical Release (A1 Pulley Release)

Indicated when:

  • Two or more corticosteroid injections have failed
  • Fixed locking (Grade III–IV)
  • Diabetic patients (who respond less to injections)

The A1 pulley is divided surgically through a small incision at the base of the finger (open release) or percutaneously with a needle (ultrasound-guided). Highly effective with rapid recovery — most patients return to full hand use within 2–4 weeks.

Recovery

  • Injection: Improvement within 5–7 days; full effect at 3–4 weeks
  • Surgical release: Return to light use within days; full strength at 4–6 weeks

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