What are the causes, clinical presentation, and treatment options for tenosynovitis?

Tenosynovitis Overview

Tenosynovitis is inflammation of the synovial sheath surrounding tendons, though most cases presenting to primary care are actually degenerative ("tendinosus") rather than truly inflammatory, despite being commonly mislabeled as "tendonitis." 1

Causes and Pathophysiology

Primary Mechanisms

• Repetitive loading/overuse injury - accounts for nearly 7% of all injury-related physician visits and is the most common cause seen in primary care 1
• Acute trauma (less common in primary care settings)
• Infectious causes:
  • Pyogenic flexor tenosynovitis (PFT) - bacterial infection, most commonly methicillin-resistant Staphylococcus aureus (38%), methicillin-sensitive S. aureus (22%), and Pasteurella multocida (13%) 2
  • Neisseria gonorrhoeae - rare but important cause, often presenting without typical urogenital symptoms 3
• Rheumatologic conditions - tenosynovitis may precede clinical RA and serve as an important biomarker 4

Anatomic Vulnerability

Tendons are hypovascular proximal to their insertion points, predisposing them to hypoxic degeneration. The osteotendinous junction is the most common site of overuse injury 1. The hand and foot are particularly susceptible due to intricate tendon arrangements required for fine motor control 5.

Clinical Presentation

Overuse Tenosynovitis

History:

• Insidious onset of load-related localized pain coinciding with increased activity 1
• Most patients report new activity or increased intensity of current activity
• Early: pain during activity that may subside after warm-up
• Progressive: pain increases in intensity/duration, eventually present at rest
• Pain quality: "sharp" or "stabbing" 1

Physical Examination:

• Inspection: Look for muscle atrophy (indicates chronicity), asymmetry, swelling, erythema
• Key finding: Joint effusions are uncommon - their presence suggests intra-articular pathology 1
• Palpation: Well-localized tenderness matching activity-related pain location
• Provocative testing: Maneuvers simulating tendon loading reproduce pain
• Red flag: Multiple symptomatic tendons warrant rheumatologic evaluation 1

Pyogenic Flexor Tenosynovitis (PFT)

Critical caveat: Only 62% of pediatric patients present with ≥3 Kanavel signs, and only 34% have all 4 signs. 9% present with 0-1 Kanavel signs 2. Therefore, absence of classic signs does not rule out PFT, particularly in children.

Kanavel Signs (in order of frequency):

1. Tenderness along flexor tendon sheath
2. Fusiform swelling
3. Pain with passive extension
4. Semiflexed posturing (least common - only 41% in pediatric cohort) 2

Gonococcal Tenosynovitis

• Classic triad: tenosynovitis, dermatitis, arthralgias (not always present)
• Important: Most patients lack purulent urethritis or positive screening tests 3
• Requires high index of suspicion and sexual history

Treatment Approach

Non-Infectious Tenosynovitis (Overuse)

First-Line Conservative Management (80% recover within 3-6 months): 1

1. Relative rest - reduce activity to decrease repetitive loading; avoid complete immobilization to prevent atrophy 1

2. Cryotherapy - ice through wet towel for 10-minute periods, most effective for acute pain relief 1

3. Eccentric strengthening exercises - proven effective and may reverse degenerative changes 1

4. NSAIDs:

   • Effective for short-term pain relief but no effect on long-term outcomes 1
   • Topical NSAIDs equally effective with fewer systemic side effects 1
   • Not superior to other analgesics 1

5. Corticosteroid injections:

   • May be more effective than oral NSAIDs for acute-phase pain relief but do not alter long-term outcomes 1
   • Use with caution - may inhibit healing and reduce tensile strength, predisposing to rupture 1
   • Optimal drugs, dosages, and techniques remain unknown 1

Specific Conditions:

• De Quervain tenosynovitis: Corticosteroid injection with thumb spica immobilization for 3-4 weeks shows statistically significant (though not clinically significant) functional benefits 6. Laser therapy and therapeutic ultrasound are most effective physical modalities 7

• Trigger finger: Extracorporeal shock wave therapy (ESWT) most effective for functional improvement and pain control 7

• Dupuytren disease: ESWT most efficient and safe; radiotherapy and radiofrequency promising at onset 7

Surgery:

• Reserve for patients failing 3-6 months of conservative therapy 1
• Effective option in carefully selected patients 1

Pyogenic Flexor Tenosynovitis

Immediate Management:

1. Empirical broad-spectrum antibiotics with MRSA coverage - essential due to 38% MRSA prevalence and 19% polymicrobial infections 2

   • All MRSA sensitive to vancomycin and trimethoprim-sulfamethoxazole
   • 83% MRSA sensitive to clindamycin 2
   • Organisms sensitive to initial regimen in 81% of cases 2

2. Surgical incision and drainage (I&D):

   • Required in all cases 2
   • 18% require repeat I&D 2
   • Approaches: limited incision (80%), midaxial incision (13%), Bruner incision (7%) 2
   • Note: Recent data shows insufficient evidence favoring operative over non-operative management regarding hospital stay or outcomes 8, but this conflicts with established practice

3. Intravenous antibiotics:

   • Median duration 4 days (range 1-16 days) 2
   • Culture-guided adjustment essential

Expected outcomes: Infection resolves in all cases with prompt I&D and culture-guided antibiotics; average hospitalization 5.1 days 2

Gonococcal Tenosynovitis

• Anti-gonococcal antibiotics may be sufficient alone 3
• Operative I&D may be unnecessary if diagnosed early 3
• Always obtain sexual history and perform routine screening 3

Imaging

Reserve imaging for:

• Unclear diagnosis after thorough history/physical
• Recalcitrant pain despite adequate conservative management
• Preoperative evaluation 1

Modalities:

• Plain radiography: Limited for soft tissue but reveals bony abnormalities 1
• Ultrasonography: Shows tendon thickening, decreased echogenicity, calcification
• MRI: Most sensitive/specific for tears, degeneration, chronic changes 1

Common Pitfalls

1. Mislabeling chronic degenerative tendinopathy as "tendonitis" - most cases are tendinosus, not inflammatory 1
2. Relying solely on Kanavel signs for PFT diagnosis - particularly unreliable in children 2
3. Missing gonococcal tenosynovitis - requires sexual history; classic symptoms often absent 3
4. Overusing corticosteroid injections - no long-term benefit and potential harm 1
5. Complete immobilization - causes atrophy; relative rest preferred 1
6. Assuming joint effusion is tenosynovitis - suggests intra-articular pathology instead 1