What is the diagnostic approach for tenosynovitis?

Diagnostic Approach for Tenosynovitis

Ultrasound is the primary diagnostic tool for tenosynovitis, offering excellent visualization of tendon sheaths with dynamic assessment capabilities and should be used as the first-line imaging modality after clinical examination. 1

Clinical Evaluation

Key Clinical Features to Assess:

• Pain along tendon course
• Swelling over the affected tendon
• Crepitus with movement
• Limited range of motion
• Tenderness to palpation
• Pain with active and passive movement
• Functional limitations

Specific Clinical Tests:

• For De Quervain's tenosynovitis: Finkelstein test (pain with ulnar deviation of the wrist with thumb flexed)
• For trigger finger: Palpation for nodules, assessment for catching or locking during finger flexion/extension
• For extensor/flexor tenosynovitis: Pain with resistance against the specific tendon action

Diagnostic Algorithm

1. Clinical Assessment

   • Detailed history focusing on:
     • Onset (acute vs. gradual)
     • Precipitating factors (repetitive movements, trauma)
     • Associated symptoms (systemic symptoms may suggest rheumatologic disease)
   • Physical examination targeting the affected area

2. Initial Imaging: Plain Radiographs

   • While not sensitive for tenosynovitis itself, radiographs help rule out other pathologies
   • Standard views based on location (e.g., AP and lateral for wrist/hand)

3. Confirmatory Imaging

   • Ultrasound (preferred first-line advanced imaging) 1

     • High-frequency transducers (≥10 MHz) for optimal visualization
     • Specific positioning:
       • Sitting position
       • Hand positioned on thigh or examining table
       • Dynamic examination with active flexion/extension of fingers 1
     • Diagnostic findings:
       • Hypoechoic halo around tendon
       • Thickened synovial sheath
       • Fluid within tendon sheath
       • Power Doppler signal indicating hypervascularity

   • MRI (alternative when ultrasound is inconclusive) 1

     • MRI without contrast is usually appropriate
     • Findings include:
       • Fluid within tendon sheath
       • Synovial proliferation
       • Tendon thickening or signal changes

Differential Diagnosis Considerations

• Exudative tenosynovitis:

  • Infectious causes (bacterial, mycobacterial, fungal)
  • Inflammatory arthritides (rheumatoid arthritis, psoriatic arthritis)
  • Crystal arthropathies (gout, pseudogout)

• Stenosing tenosynovitis:

  • De Quervain's tenosynovitis
  • Trigger finger/thumb
  • Intersection syndrome
  • Extensor carpi ulnaris tenosynovitis

• Other conditions to rule out:

  • Tendinosis/tendinopathy (no synovial sheath involvement)
  • Joint synovitis
  • Ganglion cyst
  • Carpal tunnel syndrome

Special Considerations

• Infectious tenosynovitis requires urgent diagnosis:

  • Aspiration of fluid from tendon sheath for Gram stain, culture
  • Elevated inflammatory markers (ESR, CRP)
  • Systemic symptoms (fever, malaise)

• Rheumatologic tenosynovitis:

  • Check for other joint involvement
  • Consider serologic testing (RF, anti-CCP, ANA)
  • Baseline ultrasound findings are predictive of erosive progression in inflammatory arthritis 1

• Stenosing tenosynovitis:

  • Ultrasound shows thickened retinaculum or pulley that constricts the osseofibrous tunnel 2

Common Pitfalls to Avoid

1. Missing infectious tenosynovitis - can lead to significant morbidity including tendon rupture and spread of infection
2. Confusing tenosynovitis with simple tendinopathy - treatment approaches differ
3. Inadequate ultrasound technique - proper positioning and dynamic assessment are crucial
4. Failure to consider systemic causes - tenosynovitis may be the first presentation of rheumatologic disease

Monitoring Response to Treatment

• Follow-up ultrasound can assess treatment response
• The OMERACT scale can be used to evaluate synovial hypertrophy 3
• Persistent tenosynovitis on imaging may predict erosive progression in inflammatory arthritis 1

Ultrasound and MRI are complementary techniques, with ultrasound offering advantages of lower cost, wider availability, and dynamic assessment capabilities, while MRI provides better overall soft tissue contrast and assessment of deeper structures 1.