At the Bedside

  • Classic presentation: Usually after puncture wound, bite, splinter, IV drug use, or seemingly minor trauma.
  • Kanavel signs:
  • Fusiform swelling of the digit
  • Digit held in slight flexion
  • Tenderness along the flexor tendon sheath
  • Pain with passive extension — often the earliest/highest-yield sign
  • Exam priorities:
  • Inspect for puncture wounds, bites, abscess, felon, paronychia, cellulitis.
  • Assess active/passive ROM, neurovascular status, cap refill.
  • Look for signs of deep-space hand infection or septic arthritis.
  • Workup:
  • Diagnosis is primarily clinical.
  • X-ray hand/finger: Evaluate for foreign body, fracture, gas, osteomyelitis, retained tooth fragment if bite.
  • Labs: CBC, BMP, ESR/CRP, blood cultures if febrile/systemically ill. Normal labs do not exclude.
  • Ultrasound may show fluid around tendon sheath but should not delay hand consultation.
  • Initial ED management:
  • Immediate hand surgery/orthopedic/plastic surgery consult.
  • Immobilize in position of function, elevate.
  • NPO in anticipation of operative washout.
  • Start empiric IV antibiotics covering Staph aureus including MRSA and Strep.
  • Add gram-negative/anaerobic coverage for bites, immunocompromise, water exposure, IVDU, or severe infection.
  • Tetanus update if indicated.
  • Definitive therapy:
  • Early cases may be trialed with IV antibiotics, elevation, and serial exams only under hand-surgery direction.
  • Most require urgent operative irrigation/debridement, especially if delayed presentation, purulence, necrosis, severe pain, immunocompromise, or systemic toxicity.
  • Disposition:
  • Admit for IV antibiotics, serial hand exams, and likely operative management.
  • Do not discharge suspected flexor tenosynovitis without hand-surgery agreement.
A Classic Presentation
A 34-year-old man presents with worsening right index finger pain 2 days after a puncture wound from a metal wire. The finger is diffusely swollen, held in flexion, exquisitely tender along the volar surface, and passive extension causes severe pain. X-ray shows no fracture or foreign body. You make the clinical diagnosis of pyogenic flexor tenosynovitis, update tetanus, start IV vancomycin plus ampicillin-sulbactam, elevate and splint the hand, keep him NPO, and call hand surgery for urgent operative evaluation.

Study Directive

  • Memorize and recite the 4 Kanavel signs without notes.
  • Review your institution’s empiric hand-infection antibiotic pathway, especially MRSA and bite coverage.
  • Practice a focused hand exam: inspect, vascular, sensory, motor, tendon function, passive ROM, and pain localization.
  • Look at 3 clinical images of flexor tenosynovitis and distinguish it from felon, paronychia, cellulitis, and septic arthritis.
  • Create a one-line ED disposition rule: “suspected flexor tenosynovitis = NPO + IV antibiotics + hand consult + admit.”

Recent Literature