🔑 Key Learning

  • Surgical emergency caused by infection of the flexor tendon sheath in the hand.
  • Presents with the classic Kanavel’s signs.
  • Requires urgent surgical intervention and antibiotics to prevent tendon necrosis and permanent hand dysfunction.

🧬 Pathophysiology

  • Infection of the synovial sheath that surrounds the flexor tendons of the fingers.
  • Most commonly due to penetrating trauma (e.g. bite, puncture wound), or haematogenous spread.
  • Common pathogens: Staphylococcus aureus (including MRSA), Streptococci, and Gram-negative bacilli.
  • Infection leads to increased pressure, vascular compromise, and potential tendon necrosis.

👀 Clinical Features

  • Pain, swelling, and loss of function in the affected finger.
  • Classically presents with Kanavel’s Four Cardinal Signs:
    1. Finger held in flexion
    2. Fusiform swelling (uniform swelling along the finger)
    3. Tenderness along the flexor tendon sheath
    4. Pain on passive extension of the digit
  • May also be systemic signs: fever, malaise.
Figure 226: Flexor tenosynovitis. Jonrako, CC BY-SA 4.0.

    

💊 Management

  • Urgent referral to hand surgery/plastics team if Kanavel signs are present.
  • Surgical irrigation and drainage of the tendon sheath is required to evacuate pus and decompress the sheath.
  • Empirical IV antibiotics: Flucloxacillin or co-amoxiclav

📝 Exam Clues & Clinchers

  • Penetrating trauma to finger followed by pain and fusiform swelling
  • Classic Kanavel signs — especially pain on passive extension