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- Septic Flexor Tenosynovitis -

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INFECTION, FLEXOR TENDON SHEATH

Introduction

Flexor tendon sheath infection, or pyogenic flexor tenosynovitis is an aggressive, closed-space bacterial infection that can lead to significant morbidity if not effectively managed. Pyogenic flexor tenosynovitis accounts for 2.5-9.4%1,2 of all hand infections, and treatment typically consists of intravenous (IV) antibiotics and surgical drainage of the sheath with open or closed irrigation. Despite advances in antibiotic therapy, pyogenic flexor tenosynovitis remains a clinical challenge that requires prompt diagnosis and management.  Patients present with one or more positive Kanavel's cardinal signs:

  1. Exquisite pain on passive extension of finger
  2. Exquisite tenderness along course of tendon sheath
  3. Fusiform swelling of entire digit
  4. Digit with semi-flexed posture4,5,6,8

Pathophysiology

  • Typically caused by puncture wound, although there may be not injury history and infection may have a hematogenous origin6
  • Most common bacterium responsible is Staphylococcus aureus
  • Other causes include Methicillin-resistant S aureus, S epidermidis, β-hemolytic Streptococcus species, and Pseudomonas aeruginosa
  • Rare cases can be caused by Eikenella corrodens from a human bite, Pasteurella multocida from an animal bite, Listeria monocytogenes, Clostridium difficile, Neisseria gonorrhoeae3 or shewanella algae.7

Related Anatomy

  • Distal termination of the sheath of each finger is at bony insertion of flexor digitorum profundus (FDP) tendon
  • In the thumb, the sheath terminates at the flexor pollicis longus (FPL) tendon
  • The synovial portion of sheath is a double-walled tube, considered a closed anatomic space
    • The tube is composed of an inner visceral layer (epitenon) and outer parietal layer reinforced by thickening of the retinacular pulleys
    • The synovial space is located between two layers and becomes distended under pressure from infection
    • Pressure in the sheath can spread infection into neighboring bursae and fascial spaces within the hand and may extend into the forearm through Parona's space
    • Pressure can cause ischemia and lead to tissue necrosis6
    • Digital sheath infections can spread into additional closed spaces: thumb into radial bursa; little finger into ulnar bursa; index, long & ring into mid-palmar space and bursa into the space of Parona6,8

Incidence and Related Conditions

  • Comprises 2.5-9.4% of all hand infections1,2
  • Horseshoe abscess may develop from the spread of infection from thumb to little finger or vice versa through the bursa

Differential Diagnosis

  • Herpetic whitlow
  • Septic arthritis
  • Crystal-induced arthritidies and tenosynovitis
  • Cellulitis
ICD-10 Codes

INFECTION, FLEXOR TENDON SHEATH

Diagnostic Guide Name

INFECTION, FLEXOR TENDON SHEATH

ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

DIAGNOSIS SINGLE CODE ONLY LEFT RIGHT BILATERAL (If Available)
INFECTION, TENDON SHEATH, INFECTIVE TENOSYNOVITIS        
- ELBOW   M65.122 M65.121  
- WRIST   M65.132 M65.131  
- HAND   M65.142 M65.141  

ICD-10 Reference

Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Flexor Tendon Sheath Infection (Pyogenic Flexor Tenosynovitis)
  • Flexor Tendon Sheath Infection with three Kanavel's Signs: tenderness along the flexor sheath, finger in a flexed position, and pain with passive extension.
    Flexor Tendon Sheath Infection with three Kanavel's Signs: tenderness along the flexor sheath, finger in a flexed position, and pain with passive extension.
  • Flexor Tendon Sheath Infection with puncture wound (arrow) and the fourth Kanavel sign:swelling of the entire digit.
    Flexor Tendon Sheath Infection with puncture wound (arrow) and the fourth Kanavel sign:swelling of the entire digit.
  • Flexor Tendon Sheath Infection thumb with uniform swelling of the entire thumb flexor tendon sheath and early thenar swelling.
    Flexor Tendon Sheath Infection thumb with uniform swelling of the entire thumb flexor tendon sheath and early thenar swelling.
Basic Science Photos and Related Diagrams
Spaces, Bursa and Flexor Tendon Sheaths
  • Thumb flexor tendon sheath shown separate but is connect to the radial bursa at the MP joint level and extends proximal to the transverse carpal ligament..
    Thumb flexor tendon sheath shown separate but is connect to the radial bursa at the MP joint level and extends proximal to the transverse carpal ligament..
  • Index finger flexor tendon sheath which can connect to the thenar space.
    Index finger flexor tendon sheath which can connect to the thenar space.
  • Long finger flexor tendon sheath which can connect to the mid-palmar space.
    Long finger flexor tendon sheath which can connect to the mid-palmar space.
  • Ring finger flexor tendon sheath which can connect to the mid-palmar space.
    Ring finger flexor tendon sheath which can connect to the mid-palmar space.
  • Little finger flexor tendon sheath is usually connect to the ulnar bursa.
    Little finger flexor tendon sheath is usually connect to the ulnar bursa.
  • The ulnar bursa which can connect to the radial bursa and flexor sheaths of thumb and little finger to form "horseshoe" abscess.
    The ulnar bursa which can connect to the radial bursa and flexor sheaths of thumb and little finger to form "horseshoe" abscess.
  • The hypothenar space is a potential space between the combined palmar and superficial hypothenar muscle fascia and the deep hypothenar muscle fascia. Infection is usually secondary to a puncture wound.
    The hypothenar space is a potential space between the combined palmar and superficial hypothenar muscle fascia and the deep hypothenar muscle fascia. Infection is usually secondary to a puncture wound.
  • The midpalmar space is a potential space between the volar interosseous fascia, the flexor sheath, the oblique and hypothenar septum. Infection is usually secondary to spread of infection from flexor sheath of long and ring fingers.
    The midpalmar space is a potential space between the volar interosseous fascia, the flexor sheath, the oblique and hypothenar septum. Infection is usually secondary to spread of infection from flexor sheath of long and ring fingers.
  • The thenar space is the index flexor sheath and the adductor pollicis fascia. Infection can spread here from the index flexor tendon sheath or from puncture wounds.
    The thenar space is the index flexor sheath and the adductor pollicis fascia. Infection can spread here from the index flexor tendon sheath or from puncture wounds.
  • The Parona Space is superficial to the pronator quadrates and under the flexor tendons. Infection can spread here from the radial or ulnar bursa.
    The Parona Space is superficial to the pronator quadrates and under the flexor tendons. Infection can spread here from the radial or ulnar bursa.
Symptoms
History of a puncture wound
Exquisite pain on passive extension of finger
Exquisite tenderness along course of tendon sheath
Fusiform swelling of entire digit
Digit with semi-flexed posture
Typical History

The mean age of a typical patient with pyogenic flexor tenosynovitis is a 42 year old male with an injury to a non-dominant finger, especially the long finger, that occurred several days earlier.4,6  Penetrating trauma to the finger is usually the cause of infection, although immunocompromised patients may have a more indolent and chronic presentation.5 The site of penetrating trauma is often identifiable and may appear relatively mild.5 The fingers are the most common location for infection, but it does occasionally extend into the palm.4 Most patients will exhibit one or more of Kanavel’s signs.5 Common comorbid conditions include diabetes, peripheral vascular disease (PVD) and renal failure, all of which are significantly associated with a higher risk for amputation.4

Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Treatment Goals
  • Early identification of the flexor tendon sheath infection
  • Cultures and appropriate empirical anbiotic treatment
  • Early surgical irrigation and debridement
  • Hand therapy immediately after surgery
Conservative

Intravenous antibiotics

  • May be appropriate in rare cases when patients present within 48 hours of penetrating hand trauma and the distinction between cellulitis alone and flexor sheath infection has not been made
  • IV antibiotic regimen should include presumptive coverage against common Gram-positive organisms and Gram-negative rods and anaerobes
  • If culture results are available, antibiotics should be specifically tailored to bacterial organisms identified
  • Patients should be examined regularly, and antibiotic duration depends on individual patient’s clinical response
    • If no improvement or worsening of symptoms is seen within 12-24 hours, surgical treatment including irrigation and debridement is recommended
    • If patient improves, IV antibiotics should be continued until transition can be made to specific oral antibiotics based on culture results
  • Splinting and elevation is often also prescribed
  • Hand therapy is often required to maximize digital motion recovery
Operative
  • Typically necessary if patients present after 48 hours or no improvements are detected after 24 hours of IV antibiotic treatment
    • Open irrigation and debridement
    • Closed tendon sheath irrigation
    • Continuous closed irrigation
    • Post-operative irrigation

For ASSH's Hand-e Surgical Video of Surgical Treatment of Fight Bites and Suppurative Flexor Tenosynovitis in the ER by Lalonde:

Treatment Photos and Diagrams
Flexor Tendon Sheath Infection Treatment
  • Flexor Tendon Sheath Infection I&D with catheter in the thumb flexor sheath at the MP joint level (A) used to irrigate first distal and now proximally to open carpal tunnel and open radial bursa. (B).
    Flexor Tendon Sheath Infection I&D with catheter in the thumb flexor sheath at the MP joint level (A) used to irrigate first distal and now proximally to open carpal tunnel and open radial bursa. (B).
  • Flexor Tendon Sheath Infection being treated with large amounts of saline irrigation.
    Flexor Tendon Sheath Infection being treated with large amounts of saline irrigation.
Complications
  • Loss of range of motion
  • Tendon rupture
  • Spread of infection to surrounding structures
  • Loss of skin over infected tissue
Outcomes
  • Studies on patients treated with antibiotics only are lacking, but their use has been associated with increased range of motion and better overall patient-reported outcomes4
  • Early treatment with antibiotics also may decrease the risk for surgical complications or occasionally eliminate the need for surgery entirely
  • Surgical treatment plus IV antibiotics is associated with significantly better ROM than surgery alone
  • Amputation of the affected digit is rare, but this risk increases if the patient has the following conditions and/or comorbidities: osteomyelitis, soft-tissue loss, age >43 years, diabetes/PVD, subcutaneous purulence, digital ischemia at presentation, multiple causative organisms
  • Maloon, et al reported 43% with poor results
Key Educational Points
  • Catheter irrigation results in better overall range of motion without increased risk of infection
  • The lymphatic drainage of the hand goes dorsally, so expect a large amount of dorsal hand swelling with palmar flexor tendon sheath infections.
  • Although surgery is mainstay of treatment for persistent and severe cases of pyogenic flexor tenosynovitis, it may not be the most appropriate initial intervention for patients who present early with possible cellulitis alone
  • If there is doubt, it is better to do a surgical irrigation and debridement early than late!
  • Kanavel’s four cardinal signs4,5,6,8
    1. Exquisite pain on passive extension of finger
    2. Exquisite tenderness along course of tendon sheath
    3. Fusiform swelling of entire digit
    4. Digit with semi-flexed posture
References

Cited

  1. Pang HN, Teoh LC, Yam AK, et al. Factors affecting the prognosis of pyogenic flexor tenosynovitis. J Bone Joint Surg Am 2007;89:1742–8.PMID: 17671013
  2. Weinzweig N, Gonzalez M. Surgical infections of the hand and upper extremity: a county hospital experience. Ann Plast Surg 2002;49:621–7. PMID: 12461446
  3. Draeger RW, Bynum DK Jr. Flexor tendon sheath infections of the hand. J Am Acad Orthop Surg 2012;20(6):373-82. PMID: 22661567
  4. Giladi AM, Malay S, Chung KC. A systematic review of the management of acute pyogenic flexor tenosynovitis. J Hand Surg Eur 2015;40(7):720-8. PMID: 25670687
  5. Kennedy CD, Huang JI, Hanel DP. Kanavel's Signs and Pyogenic Flexor Tenosynovitis. Clin Orthop Relat Res 2016;474(1):280-4. PMID: 26022113
  6. Maloon S, de V. de Beer J, Opitz M, Singer M. Acute flexor tendon sheath infections. J Hand Surg Am 1990;15(3):474-7.
  7. Fluke EC, Carayannopoulos NL, Lindsey RW. Pyogenic Flexor Tenosynovitis Caused by Shewanella Algae. J Hand Surg Am 2016; 41(7):e203-e206.
  8. Kanavel AB: The symptoms, signs, and diagnosis of tenosynovitis and major fascial space abscesses. In Kanavel A, ed: Infections of the Hand, 6th Edition. Philadelphia, PA, Lea and Febiger, 1933, pp. 364-395.

New Articles

  1. Draeger RW, Bynum DK Jr. Flexor tendon sheath infections of the hand. J Am Acad Orthop Surg 2012;20(6):373-82. PMID: 22661567
  2. Kennedy CD, Huang JI, Hanel DP. Kanavel's Signs and Pyogenic Flexor Tenosynovitis. Clin Orthop Relat Res 2016;474(1):280-4. PMID: 26022113

Reviews

  1. Giladi AM, Malay S, Chung KC. Management of acute pyogenic flexor tenosynovitis: Literature review and current trends. J Hand Surg Eur 2015;40(7):720-8. PMID: 25670687
  2. Abrams RA, Botte MJ. Hand Infections: Treatment Recommendations for Specific Types. J Am Acad Orthop Surg 1996;4(4):219-230. PMID: 10795057
  3. Draeger RW, Bynum DK Jr. Flexor tendon sheath infections of the hand. J Am Acad Orthop Surg 2012;20(6):373-82. PMID: 22661567