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Hand Surgery

Pyogenic Flexor Tenosynovitis

Pyogenic flexor tenosynovitis is a surgical emergency involving bacterial infection of the digital flexor tendon sheath. Delayed recognition can lead to tendon necrosis, adhesions, digital stiffness, horseshoe abscess formation, ischemia, amputation, and permanent functional impairment. This continuing medical education activity reviews flexor tendon sheath anatomy, routes of infection, causative organisms, Kanavel signs, diagnostic imaging, laboratory evaluation, staging, nonoperative treatment

v1 · Reviewed Nov 7, 2026 by Automated Clinical Reviewer (Strict Verbatim v1)
  • Pyogenic flexor tenosynovitis is a surgical emergency
  • Delayed recognition can lead to tendon necrosis, adhesions, digital stiffness, horseshoe abscess formation, ischemia, amputation, and permanent functional impairment.
  • A timely diagnosis and prompt treatment are paramount to limit the severe complications associated with this condition.
  • PFT may result in poor outcomes, including digital amputation and the spread of infection, if appropriate treatment is not promptly initiated.
  • Clinicians should clearly state that this condition is considered an emergency and necessitates urgent treatment to preserve the viability and function of the involved digit and hand.
  • The detection of the 4 Kanavel signs on physical examination has a high sensitivity (91.4% to 97.1%) for diagnosing pyogenic flexor tenosynovitis.
  • The 4 cardinal Kanavel signs of PFT include: Symmetrical (fusiform) swelling of the affected digit
  • The affected digit is held in a flexed position
  • Pain with any attempt at passive digital extension
  • Tenderness along the course of the flexor tendon sheath from the distal phalanx to the level of the A1 pulley
  • Pain with passive extension is the earliest sign of PFT, while flexor sheath tenderness is the last sign to be detected.
  • Fever is present in only 17% of affected patients.
  • Clinicians should examine the affected hand to identify any penetrating wounds.
  • The presence of erythema, swelling, and tenderness over the thenar eminence in the palm raises suspicion for proximal spread of infection to the radial bursa.
  • Anteroposterior, lateral, and oblique radiographs of the hand and affected digit should be obtained to rule out any retained foreign body.
  • PFT is characterized by greater radiographic soft tissue thickness on the volar aspect than on the dorsal aspect at the level of the proximal phalanx.
  • Hand ultrasonography is an inexpensive and noninvasive method for confirming the diagnosis of PFT.
  • Ultrasonography can help visualize the flexor tendon and detect a fluid collection within the flexor sheath.
  • Contrast-enhanced CT of the hand may be helpful in detecting PFT because the ratio of tendon sheath width to tendon width in the coronal and sagittal planes may improve diagnostic objectivity.
  • Inflammatory markers, including white blood cell count, C-reactive protein level, and erythrocyte sedimentation rate, are usually elevated in patients with PFT.
  • Cultures of pus and necrotic tissue can identify the causative organism and guide antibiotic therapy according to sensitivity results.
  • Clinicians should obtain blood cultures to isolate the causative organism if signs of sepsis or hematogenous spread of the infection are present.
  • Nonoperative treatment measures for PFT include intravenous antibiotics, elevation of the affected extremity, and splinting.
  • Broad-spectrum antibiotics should be prescribed to cover the suspected organisms until culture results are available.
  • Almost all cases of PFT require surgical treatment.
  • Flexor sheath irrigation can be performed through 2 small volar incisions.
  • Sterile normal saline is injected through the catheter to thoroughly irrigate the sheath.
  • 7- to 14-day oral antibiotic therapy is effective postoperatively, allowing for outpatient treatment.
Broad-spectrum antibiotics
Not specified in source
Adult
Not specified in source
Renal
Not specified in source
Duration
Not specified in source
  • PFT may be treated nonoperatively when a patient presents within 48 hours after a penetrating hand injury and has less pronounced Kanavel signs.
  • If clinical improvement does not occur or the Kanavel signs worsen, an urgent surgical washout should be performed.
  • Open flexor sheath irrigation and debridement : Open flexor sheath washout is generally reserved for more advanced PFT or in the presence of concomitant abscess formation.
  • The radial and ulnar neurovascular bundles of the involved digit should be identified and protected.
  • The A2 to A4 pulleys should be protected to avoid postoperative flexor tendon bowstringing.
  • The Bruner incision aims to avoid vertical scarring at the flexor creases, thereby minimizing the risk of flexion contractures.
  • However, a Bruner incision may increase the risk of postoperative wound breakdown.
  • This risk can be minimized by avoiding wound closure under tension.
  • Open flexor sheath irrigation and debridement are associated with a higher risk of postoperative digital stiffness and tendon adhesions.
  • PFT caused by hematogenous spread is rare and raises suspicion for disseminated gonococcal infection.
  • In immunocompromised individuals, PFT may be caused by a broader range of pathogens, including gram-negative rods.
  • Eikenella corrodens is a known etiologic agent in cases arising from penetrating human bites, while Pasteurella multocida is frequently implicated in infections following animal bites.
  • Nonoperative PFT treatment requires close monitoring of the infection through repeated hand examinations and monitoring of inflammatory markers.
  • If clinical improvement does not occur or the Kanavel signs worsen, an urgent surgical washout should be performed.
  • Clinicians should recommend early active exercises for the affected digit to minimize the risk of stiffness.
  • Flexor tenolysis of the affected digit may be required to restore range of motion after complete resolution of the inflammatory process.
  • Scarred and damaged flexor tendons lose elasticity and may rupture with further activity.
  • Critical ischemia of the affected digit may result from interruption of blood flow due to elevated pressure within the digit or from arterial thrombosis induced by the inflammatory process.
  • Horseshoe abscess formation may result from the spread of infection associated with PFT of the first or fifth digit in patients with communicating ulnar and radial bursae.
  • Digital amputation at various levels may be unavoidable because of deep infection, significant soft tissue damage, or a nonfunctional, stiff digit.
  • Patients with diabetes mellitus, peripheral vascular disease, or renal failure are at greater risk of digital amputation following PFT.
  • Rehabilitation after PFT requires early involvement of a hand therapist and early initiation of active range-of-motion exercises.
  • review
    Pyogenic Flexor Tenosynovitis. StatPearls [Internet] — Shady Hermena, Bryan G. Beutel, Vivek Tiwari — StatPearls Publishing, 2026

Decision support only. Verify against local protocols and current labeling. Source: www.ncbi.nlm.nih.gov